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Chewing gum selectively improves aspects of memory in healthy volunteers
... The previous studies reported an effect of mastication on cognitive tests related to arousal (Nageishi et al., 1993), shortened reaction time (Chu, 1994), and working memory (Baker et al., 2004;Stephens & Tunney, 2004;Wilkinson et al., 2002). Furthermore, functional magnetic resonance imaging (fMRI) studies have revealed increased brain activity in specific regions during mastication, including the prefrontal cortex, anterior cingulate cortex, and left frontal gyrus during mastication (Higaki et al., 2016;Hirano et al., 2013). ...
... However, increased blood glucose levels resulting from food ingestion may reduce cognitive processing time (Sakamoto et al., 2009), increased working memory (Baker et al., 2004;Stephens & Tunney, 2004;Wilkinson et al., 2002), and shortened reaction time (Chu, 1994). Thus, it appears that mastication can increase brain activity and potentially improve cognitive function, including inhibitory control. ...
... Previous studies have shown that elevated blood glucose levels can have a positive impact on cognitive function (cf : Banks et al., 2012), including shortened cognitive processing time (Hawkins et al., 2018), increased working memory (Baker et al., 2004;Stephens & Tunney, 2004;Wilkinson et al., 2002), and shortened choice reaction times (Chu, 1994). It is also known that insulin, which is secreted by the pancreas in response to elevated blood glucose levels. ...
Mastication leads to an immediate enhancement in cognitive functions, including inhibitory control. Furthermore, the hardness of the food increases sympathetic nerve activity during and immediately after mastication. Hence, the cognitive function could be enhanced by increased sympathetic nerve activity. The present study aimed to investigate the effects of food hardness on cognitive inhibitory control function in humans. The participants were 23 healthy adults (19-22 years old). Experiments were conducted with two types of gummies (soft and hard). The participants ingested 13 g of gummies and performed a stop-signal task to measure cognitive inhibitory control function after they rested for 5 min. The reaction time for the stop-signal task after gummy consumption was significantly shorter in the hard gummy condition compared to the soft gummy condition (p < .05). Furthermore, the accuracy rate of the responses was also significantly higher in the hard gummy condition compared to the soft gummy condition (p < .05). The results of the present study suggest that food hardness enhances cognitive inhibitory control function in humans.
... The impact of chewing on maxillofacial development, stomatognathic system balance, and central motor control are extensively documented in the literature [11,12]. Several experimental and epidemiological studies have investigated the relationship between chewing function and cognitive status or cerebral activation [13][14][15][16]. In particular human experimental studies have shown that short-term use of chewing gum results in increased regional cerebral blood flow and enhancement of cognitive function, such as working memory [15,16]. ...
... Several experimental and epidemiological studies have investigated the relationship between chewing function and cognitive status or cerebral activation [13][14][15][16]. In particular human experimental studies have shown that short-term use of chewing gum results in increased regional cerebral blood flow and enhancement of cognitive function, such as working memory [15,16]. Evidence from the transcriptomic investigation has also suggested that chewing function may modify the functions of microglia in the brain, which in turn may affect the neuroimmune activity and cognitive function [17]. ...
... Nutrients 2023, 15, 1168 ...
Food hardness is one of the dietary features that may impact brain functions. We performed a systematic review to evaluate the effect of food hardness (hard food versus soft food diet) on behavior, cognition, and brain activation in animals and humans (PROSPERO ID: CRD42021254204). The search was conducted on 29 June 2022 using Medline (Ovid), Embase, and Web of Science databases. Data were extracted, tabulated by food hardness as an intervention, and summarized by qualitative synthesis. The SYRCLE and JBI tools were used to assess the risk of bias (RoB) of individual studies. Of the 5427 studies identified, 18 animal studies and 6 human studies met the inclusion criteria and were included. The RoB assessment indicated that 61% of animal studies had unclear risks, 11% had moderate risks, and 28% had low risks. All human studies were deemed to have a low risk of bias. The majority (48%) of the animal studies showed that a hard food diet improved behavioral task performance compared to soft food diets (8%). However, 44% of studies also showed no differential effects of food hardness on behavioral tests. It was also evident that certain regions of the brain were activated in response to changes in food hardness in humans, with a positive association between chewing hard food, cognition performance, and brain function. However, variations in the methodologies of the included studies hindered the meta-analysis execution. In conclusion, our findings highlight the beneficial effects of dietary food hardness on behavior, cognition, and brain function in both animals and humans, however, this effect may depend on several factors that require further understanding of the causality.
... The two reviewers disagreed over the classification of 47/927 papers in their independent reviews (5.64%). A consensus meeting was used to decide on the ultimate inclusion and exclusion of the disputed papers resulting in a final list of 21 publications [1][2][3][4][5]14,18,21,22,24,38,[50][51][52][53][54]57,59,60,62,64]. ...
... Previous research has suggested that heart rate declines over time during a sustained attention task [44]. Wilkinson et al. found that heartrate was increased when chewing gum compared with when participants did not chew gum [64]. They also observed improvements in cognitive function and suggested that mastication may have increased regional cerebral blood flow and increased insulin release [64]. ...
... Wilkinson et al. found that heartrate was increased when chewing gum compared with when participants did not chew gum [64]. They also observed improvements in cognitive function and suggested that mastication may have increased regional cerebral blood flow and increased insulin release [64]. However, to investigate whether these effects were linked to stress, Allen & Smith measured cortisol and heart-rate during the course of a working day. ...
The aims of this paper are to conduct: 1) a systematic review of the effects of mastication on sustained attention, and 2) a meta-analysis of the effects of mastication on the performance of participants undertaking cognitive tests. Papers were obtained from MEDLINE and PsycInfo using a systematic approach incorporating defined inclusion and exclusion criteria. Twenty-one papers linking mastication and sustained attention were reviewed. Meta-analysis detected a weak, but statistically significant, improvement in levels of sustained attention when chewing with low between-study heterogeneity (mean Cohen's d = −0.1479 standard deviations, 95% CI [−0.2913, −0.0045], p = 0.043 & I² = 0.00%), and a tendency for feelings of alertness to decrease less during cognitive demanding tasks when chewing (mean Cohen's d = 0.3797 standard deviations, 95% CI [−0.0053, 0.7647], p = 0.052 & I² = 70.94%). To better understand the effects of mastication on sustained attention and alertness, further research is required which refines existing protocols, eliminates confounding effects such as gum formulation and constituents, and investigates the effects of contiguity, rate, and intensity of chewing.
... There are a range of theoretical perspectives considering why chewing gum might facilitate cognitive performance. The first major account holds that chewing gum induces arousal; thus, several studies have reported chewing gum increases/improves cerebral blood flow (Hirano & Onozuka, 2015;Tucha, Mecklinger, Maier, Hammerl, & Lange, 2004;Wilkinson, Scholey, & Wesnes, 2002) as well as brain activity (Hirano et al., 2008) and an increase in heart rate, and blood pressure (Allen, Jacob, & Smith, 2014;Smith, 2010;Wilkinson et al., 2002). A few studies have reported that chewing gum increases levels of arousal by affecting the central and sympathetic nervous systems (Allen et al., 2014;Sakamoto, Nakata, & Kakigi, 2009). ...
... There are a range of theoretical perspectives considering why chewing gum might facilitate cognitive performance. The first major account holds that chewing gum induces arousal; thus, several studies have reported chewing gum increases/improves cerebral blood flow (Hirano & Onozuka, 2015;Tucha, Mecklinger, Maier, Hammerl, & Lange, 2004;Wilkinson, Scholey, & Wesnes, 2002) as well as brain activity (Hirano et al., 2008) and an increase in heart rate, and blood pressure (Allen, Jacob, & Smith, 2014;Smith, 2010;Wilkinson et al., 2002). A few studies have reported that chewing gum increases levels of arousal by affecting the central and sympathetic nervous systems (Allen et al., 2014;Sakamoto, Nakata, & Kakigi, 2009). ...
... One of the first empirical studies to examine the effects of chewing gum on memory by Wilkinson et al. (2002) used immediate and delayed recall of words to examine short-term and long-term memory performances and found that participants who chewed gum displayed significantly better performance results. Following the success of this study, there were a number of attempts to replicate these effects of chewing gum on memory. ...
Recent research has demonstrated chewing gum can enhance various cognitive processes associated with learning, but most studies have used cognitive functioning tasks (e.g., selective attention, working memory) as outcomes. Across two experiments, we investigated effects of chewing gum on self‐reports of alertness and test performance following study of realistic educational materials. In Experiment 1 (n = 40), adult participants who chewed gum while studying a 20‐minute physiology lesson outperformed a non‐chewing condition on subsequent terminology and comprehension tests, but did not report higher levels of post‐lesson alertness as hypothesised. In Experiment 2 (n = 39), adult participants who chewed gum while studying a 9‐minute lesson on a mental mathematics strategy outperformed a non‐chewing condition on a subsequent problem‐solving test, while also reporting higher levels of post‐lesson alertness. The results provide initial support for chewing gum while studying realistic educational materials across a range of topics and study durations.
... Numerous studies have reported the influence of chewing on the cognitive function (Endo et al., 1982;Nageishi et al., 1993;Otomaru et al., 2003;Yokoyama et al., 2017;Suzuki et al., 1992Suzuki et al., , 1994Chu, 1994;Wilkinson et al., 2002;Baker et al., 2004;Stephane and Tunney, 2004). It has been suggested that chewing results in increased brain activity (Endo et al., 1982;Nageishi et al., 1993;Otomaru et al., 2003;Yokoyama et al., 2017), increased energy consumption (Suzuki et al., 1992;Suzuki et al., 1994), shortened selective reaction time (Chu, 1994), and increased working memory (Wilkinson et al., 2002;Baker et al., 2004;Stephane and Tunney, 2004) along with other effects. ...
... Numerous studies have reported the influence of chewing on the cognitive function (Endo et al., 1982;Nageishi et al., 1993;Otomaru et al., 2003;Yokoyama et al., 2017;Suzuki et al., 1992Suzuki et al., , 1994Chu, 1994;Wilkinson et al., 2002;Baker et al., 2004;Stephane and Tunney, 2004). It has been suggested that chewing results in increased brain activity (Endo et al., 1982;Nageishi et al., 1993;Otomaru et al., 2003;Yokoyama et al., 2017), increased energy consumption (Suzuki et al., 1992;Suzuki et al., 1994), shortened selective reaction time (Chu, 1994), and increased working memory (Wilkinson et al., 2002;Baker et al., 2004;Stephane and Tunney, 2004) along with other effects. In addition, the results of neurophysiological studies report that brain activity increases during chewing (Hasegawa et al., 2013) and that cognitive processing time, such as P300, which is event related potential, shortens after chewing (Sakamoto et al., 2009). ...
... It is said that an increase in the blood glucose level affects brain activity. Many previous studies have reported that an increased blood glucose level shortens the cognitive processing time (Sakamoto et al., 2009), increases the working memory (Wilkinson et al., 2002;Baker et al., 2004;Stephanes and Tunney, 2004), shortens the selection reaction time (Chu, 1994). Insulin is secreted from the pancreas in response to elevated blood glucose levels and acts to lower blood glucose level. ...
... To investigate the hypothesis that chewing gum increases cognitive performance, this study was designed to evaluate and compare the effects of chewing gum on cognitive performance among healthy male and female subjects. It was found that visual short term memory was increased among both the genders as a result of chewing gum which is consistent with the previous research, as it determined that chewing sugar-free gum improved aspects of verbal and visual memory 13 . ...
... It was found that selective attention was increased among males but it was relatively decreased in females following chewing gum. This is because it has been assumed that the cognition-enhancing effect of gum chewing is caused by an increased release of insulin and a changed pattern of regional cerebral blood flow, in particular in fronto-temporal regions of the brain 13,21,22 . Furthermore, it has been determined through the researches that the Inferior Parietal Lobule is larger in males than females 23 and is related to the mathematical capacity and permits the brain to process data from senses and help in selective attention and perception 24 . ...
Background: Chewing before performing a cognitive task increases oxygen levels in the Central Nervous System (CNS) areas important for processes of learning and memory. This study was done to evaluate and compare the effects of chewing gum on reaction time, visual short term memory, selective attention, verbal and non-verbal reasoning, and problem-solving ability in healthy male and female subjects. Methodology: The comparative, gender-based, interventional study was conducted involving 300 individuals placed in the control (n=150) and interventional group (n=150). Participants in the interventional group were required to chew gum till they completed the task. A questionnaire was designed to record the reaction time, memory, attention, executive and intellectual functioning and time took to solve each parameter. Each subject in both control and interventional group completed the questionnaire with and without chewing gum, respectively. Results for the two groups were compared using SPSS version 20.0. Results: It was found that the gum chewing group performs significantly better than the control group, thus chewing gum significantly improves cognitive performance. These cognitive effects of chewing were comparable among the two genders but relatively more pronounced among male participants as compared to females. Conclusion: Chewing gum is positively associated with higher level of cognitive performance than controls.
... To investigate the hypothesis that chewing gum increases cognitive performance, this study was designed to evaluate and compare the effects of chewing gum on cognitive performance among healthy male and female subjects. It was found that visual short term memory was increased among both the genders as a result of chewing gum which is consistent with the previous research, as it determined that chewing sugar-free gum improved aspects of verbal and visual memory 13 . ...
... It was found that selective attention was increased among males but it was relatively decreased in females following chewing gum. This is because it has been assumed that the cognition-enhancing effect of gum chewing is caused by an increased release of insulin and a changed pattern of regional cerebral blood flow, in particular in fronto-temporal regions of the brain 13,21,22 . Furthermore, it has been determined through the researches that the Inferior Parietal Lobule is larger in males than females 23 and is related to the mathematical capacity and permits the brain to process data from senses and help in selective attention and perception 24 . ...
Background: Chewing before performing a cognitive task increases oxygen levels in the Central Nervous System (CNS) areas important for processes of learning and memory. This study was done to evaluate and compare the effects of chewing gum on reaction time, visual short term memory, selective attention, verbal and non-verbal reasoning, and problem-solving ability in healthy male and female subjects.
Methodology: The comparative, gender-based, interventional study was conducted involving 300 individuals placed in the control (n=150) and interventional group (n=150). Participants in the interventional group were required to chew gum till they completed the task. A questionnaire was designed to record the reaction time, memory, attention, executive and intellectual functioning and time took to solve each parameter. Each subject in both control and interventional group completed the questionnaire with and without chewing gum, respectively. Results for the two groups were compared using SPSS version 20.0.
Results: It was found that the gum chewing group performs significantly better than the control group, thus chewing gum significantly improves cognitive performance. These cognitive effects of chewing were comparable among the two genders but relatively more pronounced among male participants as compared to females.
Conclusion: Chewing gum is positively associated with higher level of cognitive performance than controls.
... Positive effects of chewing gum on cognitive functions have been described in numerous studies. Chewing gum can improve memory and concentration functions in healthy children and adults [18][19][20]. It has been suggested that gum chewing can influence cerebral blood flow and suppression of insulin secretion [21]. ...
... In the research by Sakamoto et al. [18], improvements in concentration were only noticeable when chewing took place before the work began and remained only during the first twenty minutes of cognitive work. There are also data that do not confirm the relationship between chewing gum and improvement in attention among ADHD children [19,22,23]. ...
Objectives:
The aim of the study was to compare the prevalence of parafunctions and signs and symptoms of TMD in a population group of children with and without ADHD.
Methods:
The study included all 5th grade children of all public primary schools in Sopot (untreated, unguided children). The reporting rate was 91%. At the first stage of the psychological-psychiatric study both parents and children filled in the CBCLand YSR questionnaires. At the next stage, in the group of children selected during the screening, aqualified child psychiatrist conducted asemi-structured diagnostic interview K-SADS-PLand diagnosed ADHD. Parafunctions, signs and symptoms of TMD were assessed by conducting a direct interview with a child and a clinical examination by a dentist.
Results:
There were significant differences (p < 0.05) between children with ADHD and without ADHD associated with parafunctions such as chewing gum (76.47% vs. 46.07%), nail biting (70.59% vs. 40.45%) and bruxism (52.54% vs. 26.22%), the number of signs and symptoms of TMD (1 sign or symptom 0.0% vs. 32.21%; 4-7 signs or symptoms 17.65% vs. 3.75%).
Conclusions:
In children with ADHD, symptoms of temporomandibular joint disorders and parafunctions were significantly more frequent. These studies suggest that children with ADHD constitute agroup of increased risk for TMD in the future. Interdisciplinary treatment of an ADHD patient by a psychiatrist and a dentist is necessary.
... Possible explanations for the effect of chewing gum on cognitive function may be related to a bilateral increases of neuronal activity within some areas of the brain (e.g., sensorimotor cortex, supplementary motor area, prefrontal cortex, insula, cerebellum, and thalamus) [15,16], as well as an increased release of insulin and an increased cerebral blood flow [7,14,15,17]. Shiba et al. [18] also found suppression of the parasympathetic nervous activity and/or enhancement of the sympathetic nervous activity for the heart of healthy adults after chewing gum. Thus, it seems that chewing gum might play a role in the modulation of autonomic nervous activity in healthy adults. ...
... Also, chewing gum by itself might lead to positive behavioral changes in healthy individuals [6,7]. Indeed, a recent systematic review and meta-analysis reported that there is a modest link between chewing gum and sustained attention in healthy adults [8]. ...
Background: There is some evidence showing significant correlations between acute chewing gum and orofacial function, and between acute chewing gum and cognitive function; however, as far as we are aware, little is known about the chronic effects of chewing gum training on cognitive and orofacial functions in healthy adults. Objectives: To evaluate the chronic effects of chewing gum training on orofacial and cognitive functions in healthy adults. Method: Searches of the electronic databases PubMed, Scopus, BVS, CENTRAL, Scopus, and Google Scholar were conducted from inception to 14 January 2020. The inclusion criteria used were: clinical trial or randomized controlled trial lasting a minimum of four weeks, chewing gum intervention in at least one arm of the study, presence of a non-exercise control group, study population consisting of healthy adults, study outcomes consisting of orofacial function and/or cognitive function. Results: Starting from 5973 sources, a total of six articles met the inclusion criteria, and they were subjected to a systematic review. The main findings were that chewing gum training improved some variables related to orofacial function. No clear effect of chewing gum training on cognitive function was found. Conclusions: Chronic chewing gum training has an unclear positive effect on specific variables related to orofacial and cognitive function in healthy adults.
... Chewing gum is quite affordable and students report using it for many reasons. Students, especially college students, eat chewing gum, not just as mere snack, but also as substance that can help to improve concentration (Wilkinson, Scholey, & Wesnes, 2002), reduce stress (Zibell & Madansky, 2009), and to increase alertness (Johnson, Jenks, Mills, Albert, & Cox, 2011), especially when feeling sleepy (Wenk, 2012). ...
... The findings of this research have some practical applications to teaching and learning. One of the most important educational implication of this study is in a large body of evidence (e.g., Allen & Smith, 2011;Onyper, et. al., 2011;Wilkinson, et. al., 2002), which show that chewing gum improves memory when taken prior to a test. Chewing gum results in significant improvement of memory, it improves regional cerebral blood flow in the frontal-temporal regions, which are believed to mediate aspects of memory functioning (Sesay, et. al., 2000). Also, eating chewing gum promotes the release of ...
The study examined whether chewing gum would facilitate recall performance and
if females would perform better than males on verbal recall. Participants for the study were
120 undergraduate students of University of Nigeria, Nsukka. There were 60 males and 60
females (Mean age = 21.13 years; SD = 2.17). Oral prose assessment test 1 (OPAT 1) was
the source for data collection. A between-groups ANOVA statistics was used for data
analyses, and results showed that neither chewing gum nor gender has a simple
independent effect on recall memory (p <0.05; ŋ2 = 0.31). The implication of the finding is
that chewing gum has some facilitating influence on recall, but that is only for female
participants. Also, overall performance on the OPAT 1 showed that females were better
than males recall memory (p <0.05). Discussion implores teachers not to discourage the
consumption of chewing gum in the classrooms, since it has the possibility to enhance
recall ability.
... However, randomized controlled trials specifically investigating the effects of aqueous spearmint (Mentha spicata L.) extracts, a member of the Lamiaceae family, on cognitive function are limited. A few studies have been conducted evaluating the effects of small quantities of spearmint oil in spearmint chewing gum on memory in healthy volunteers, which report conflicting results [14][15][16]. Previous work in rodents with an aqueous spearmint extract found that 320 and 640 mg/kg body weight of the extract (16 and 32 mg rosmarinic acid/kg body weight), equivalent to 600-1200 mg of the spearmint extract on average for humans, were effective in improving memory and learning in a SAMP8 mouse model of accelerated aging [17,18]. ...
... Conflicting evidence exists regarding the effects of spearmint on cognitive function and are limited to spearmint chewing gum specifically. Mint chewing gum is commonly formulated with oil extracts and contains small amounts of extract, typically 0.1-5% (w/w), but the composition and quantity of spearmint extract used in these trials were not described [14,15]. Furthermore, the interpretation of these results is difficult, due to the absence of dosing information; it is also uncertain whether the improvement in memory and attention/concentration is the result of spearmint or the act of chewing, as a number of studies suggest the act of chewing alone may support cognitive function [47]. ...
Background:Cognitive function can decline during theagingprocess andsignificantly reducequality of life. Although a number of interventionshave been investigatedforcognitive dysfunction, including antioxidants,this prominent health concern warrants further explorationof additionalmethods to support cognitive health later in life. An aqueous extract from a proprietary spearmint line has been developed which contains a number of antioxidant compounds, including rosmarinic acid,athigherlevels than typically found incommercially-bred spearmint. Therefore, this pilot trialassessedthe tolerance, bioavailability,andpotential cognitive health implications ofa proprietary spearmint extractin men and women with self-reported memory impairment.Methods:Subjectsconsumed 900 mg/dayspearmint extract for 30 days. The sample population (N = 11) was73% femaleand 27% male with amean age of 58.7± 1.6 y. Tolerabilityparameters were assessed at baseline and end of treatmentvisits. Computerized cognitive function tests were completed and blood was drawnat pre-and post-dose (0.5 to4 h) timepoints duringbaseline and end of treatmentvisits.Subjective cognitionwas also assessed atthe end of treatment.Results:Neitherserious adverse events nor clinically relevant findings were observed in anytolerabilityparameters.Plasmavanillic, caffeic, and ferulic acid sulfates, rosmarinic acid, and methyl rosmarinic acid glucuronide were detected in plasma following acute administration of the spearmint extract. Computerized cognitive function scores improved in reasoning(P =0.023)and attention/concentration(P = 0.002) after 30 days of supplementation.After acute administration,subjects had improvedattention/concentrationin two tests at 2 (P = 0.042and P = 0.025) and 4 h (P = 0.001 and P = 0.002).Conclusions: The results from this pilot trial suggestthatthe spearmint extract,which containshigherrosmarinic acid contentrelative to extracts from typical commercial lines, was well-toleratedat 900 mg/day. The extract was alsobioavailable.Further investigation is warranted regarding its potential for supporting cognitive health.
... Chewing gum is a confectionary product commonly enjoyed by consumers of a wide range of ages. There have been studies that claim that chewing gum can improve memory (Wilkinson et al. 2002), prevent stress (A. P. Smith 2009), and promote positive mood, attention, and alertness (A. ...
Chewing gum is a commonly used food product, and sugar‐free chewing gum consumption is also frequent. Although artificial sweeteners, such as aspartame, are used in food recipes to replace sugar, they can be associated with health problems. Thus, it is necessary to develop products with natural sweeteners and polyols as sugar substitutes. This study aimed to investigate the use of stevia and xylitol in the production of chewing gum. Four different recipes for chewing gums (sorbitol + aspartame, sorbitol + stevia, sorbitol + xylitol + aspartame, and sorbitol + xylitol + stevia) were created by keeping the amounts of the ingredients other than the sweeteners and polyols constant. The differences in the color, texture, and sensory properties of the chewing gum samples were evaluated. Accelerated shelf‐life test (AST) was also employed to evaluate the stability of the samples during storage. The substitution of sorbitol with xylitol caused color changes (decreased L*, a*, and h° values) and decreased the hardness, springiness, and overall likeliness of the samples; however, the use of stevia did not affect the color, texture, and sensory properties of the samples compared to the aspartame‐containing samples. Thus, the findings of this study suggest that stevia can be used in chewing gum production as an alternative to aspartame without causing any adverse effects on the color, texture, and sensory properties.
... For example, it was observed that gum chewing was beneficial to working memory, episodic longterm memory, and attention. [8][9][10] In these studies, the use of functional magnetic resonance imaging (fMRI) was introduced to elucidate the neural correlates for the chewing effects, [11][12][13][14] whereby it has been reported that gum chewing induced neural activation in various brain regions. 15 Some fMRI studies have focused on the orofacial motor system related to mastication, such as chewing movements, whereas others examined the influence of chewing on neuronal activities in the brain during a cognitive task using fMRI. ...
Introduction and aims
Recent findings suggest a potential correlation between mastication and cognitive processes. However, the comprehensive investigation into the neurobiological mechanisms of masticatory control, such as the impact of chewing hardness, on cognitive function, remains incomplete. This study aims to investigate the impact of chewing hardness, as an aspect of masticatory control, on cognitive function by examining brain activation patterns during hard and soft chewing conditions.
Methods
A total of 52 healthy young adults (average age of 21.81 years; 24 men and 28 women) underwent fMRI scanning, during which 27 individuals chewed soft and 25 individual chewed hard material. The functional magnetic resonance imaging (fMRI) was employed to elucidate the overlapping and distinct patterns of activated brain regions associated with soft- and hard-chewing conditions. Subsequently, correlations between these activated brain regions and neuropsychological measures were assessed.
Results
Conjunction analysis revealed that both soft- and hard-chewing conditions stimulated brain regions directly associated with orofacial movement and spatial information processing. Two-sample t-test result indicated that the hard-chewing group had higher activation mostly in the caudate nucleus and frontal brain regions associated with cognitive function compared with the soft-chewing group. Furthermore, the activation strength of these brain regions positively correlated with neuropsychological measures.
Conclusion
The findings suggest that hard-chewing may be more effective than soft-chewing in stimulating cognition-associated brain regions, potentially enhancing cognitive processing.
Clinical relevance
Our study shows that hard-chewing activates brain regions linked to cognitive function more than soft-chewing. This suggests that harder chewing could be used as a simple, non-invasive method to enhance cognitive processing. Incorporating harder foods into the diet may offer a practical approach to support cognitive health and improve mental performance.
... Decreased articulatory function and tongue pressure caused by oral diadochokinesis are reported to correlate with decline in cognitive function [10], suggesting that the maintenance of oral function is essential for the prevention of cognitive function decline. Gum chewing is reported to improve episodic memory and working memory in young adults [11]. Furthermore, the dorsolateral prefrontal cortex (DLPFC) is reported to be activated during lip-closure training in older adults [12]. ...
Background
Cognitive function plays a crucial role in human life, and its maintenance and improvement are essential in both young and older adults. Since cognitive decline can be associated with oral function decline, preventing the decline in both cognitive and oral functions is an urgent social issue. Several training methods to improve each function have been proposed. Previous studies have indicated that greater brain activity during training is associated with increased benefits for cognitive function. Although adding cognitive function elements to oral function training may promote the activation of brain activity during oral function training, the effects have not been validated. The main purpose of this study is to develop a novel training program that combines oral function training with cognitive training, which is expected to activate key brain regions involved in oral and cognitive functions, such as the left dorsolateral prefrontal cortex (DLPFC) and right medial prefrontal cortex (mPFC).
Methods
Four types of training programs combining oral and cognitive training: PaTaKaRa × calculation, lip exercise × N-back, tongue exercise × inhibition, and tongue exercise × memory, were developed. Each program had seven levels of difficulty [level 0 (no cognitive load) and level 6 (maximum difficulty)]. Twelve healthy young adults participated in the study and were instructed to perform all four programs. Brain activity in the left DLPFC and right mPFC were measured during each training session using two-channel near-infrared spectroscopy (NIRS).
Results
No significant brain activity was observed during training at level 0. Brain activity in the left DLPFC was significantly increased at levels 1 and 2 and in the left DLPFC and right mPFC at level 6 during PaTaKaRa × calculation training. Brain activity in the left DLPFC was significantly increased at level 6 during tongue exercise × inhibition training. Brain activity in the left DLPFC and right mPFC was significantly increased at level 6 during lip exercise × N-back training.
Conclusion
Oral function training did not significantly increase brain activity; nevertheless, oral function with cognitive training stimulated brain activity in the prefrontal cortex.
Trial registration
: UMIN-CTR. ID: UMIN000039678. date: 06/03/2020.
... Decreased articulatory function and tongue pressure caused by oral diadochokinesis are reported to correlate with decline in cognitive function [10], suggesting that the maintenance of oral function is essential for the prevention of cognitive function decline. Gum chewing is reported to improve episodic memory and working memory in young adults [11]. Furthermore, the dorsolateral prefrontal cortex (DLPFC) is reported to be activated during lip-closure training in older adults [12]. ...
Background
Cognitive function plays a crucial role in human life, and its maintenance and improvement are essential in both young and older adults. Since cognitive decline can be associated with oral function decline, preventing the decline in both cognitive and oral functions is an urgent social issue. Several training methods to improve each function have been proposed. Previous studies have indicated that greater brain activity during training is associated with increased benefits for cognitive function. Although adding cognitive function elements to oral function training may promote the activation of brain activity during oral function training, the effects have not been validated. This study aimed to develop a novel training program that combines oral function training with cognitive training, which is expected to activate key brain regions involved in oral and cognitive functions, such as the left dorsolateral prefrontal cortex (DLPFC) and right medial prefrontal cortex (mPFC).
Methods
Four types of training programs combining oral and cognitive training: PaTaKaRa × calculation, lip exercise × N-back, tongue exercise × inhibition, and tongue exercise × memory, were developed. Each program had seven levels of difficulty [level 0 (no cognitive load) and level 6 (maximum difficulty)]. Twelve healthy young adults participated in the study and were instructed to perform all four programs. Brain activity in the left DLPFC and right mPFC were measured during each training session using two-channel near-infrared spectroscopy (NIRS).
Results
No significant brain activity was observed during training at level 0. Brain activity in the left DLPFC was significantly increased at levels 1 and 2 and in the left DLPFC and right mPFC at level 6 during PaTaKaRa × calculation training. Brain activity in the left DLPFC was significantly increased at level 6 during tongue exercise × inhibition training. Brain activity in the left DLPFC and right mPFC was significantly increased at level 6 during lip exercise × N-back training.
Conclusion
Oral function training did not significantly increase brain activity; nevertheless, oral function with cognitive training stimulated brain activity in the prefrontal cortex.
Trial registration
UMIN-CTR. ID: UMIN000039678. date: 06/03/2020
... In one of his studies, the latter showed how the reaction time to the auditory oddball paradigm substantially decreased in the phase immediately after the end of a chewing exercise [7]. Similarly, in a study conducted by Wilkinson, the author explained that chewing gum can raise a subject's learning skills [28]. Kawakami too highlighted a reduced reaction time to the Stroop test during a gum chewing exercise [3]. ...
Chewing is one of the most important orofacial functions. Over the last twenty years, a number of authors have examined the correlation between an efficient chewing function and different aspects of body functions: implementation of cognitive functions, reduction of nociceptive impulse propagation, reduced levels of stress, reduced risk of developing atherosclerosis and desaturation, limitation of eating disorders and constipation. Starting from the above considerations, this study aims at investigating the correlation between occlusal balance – without which there would be no proper mastication – and fundamental aspects as cognitive function, stress, arousal and concentration. For this purpose, we used specific tools and software to observe the electrical activity of the brain in 10 healthy volunteers. All the measurements for each participant have been carried out in three different phases: a first phase in which all the individuals were in a condition of initial occlusion; a second phase in which the occlusion was modified using a functional orthodontic device; and a third phase, in which individuals removed the device. The variations between three phases have been evaluated by using the Student’s t-test, and we considered them significant for p<0.05. The results have highlighted a significant variation in terms of stress, arousal and concentration among the three phases.
... This is not the case with trigeminal stimulation that occurs during chewing activity, which is based on both motor and sensory signals. Chewing improves cognitive performance [8], memory and learning [9][10][11] (see however [12,13]), and reduces the visual reaction time of subjects [8]. These effects are coupled with an increase in cerebral blood flow in the brain regions engaged in the performed task [8]. ...
Chewing improves visuospatial performance through locus coeruleus (LC) activation. The effects of bilateral and unilateral mastication were investigated in subjects showing different degrees of asymmetry in masseter electromyographic (EMG) activity during clenching and in pupil size at rest (anisocoria), which is a proxy of LC imbalance. Correlations between performance changes and asymmetry values were found in males, but not in females. Among males, subjects with low asymmetry values (balanced-BAL) were more sensitive than those with high asymmetry values (imbalanced-IMB) to bilateral and unilateral chewing on the side with higher EMG activity (hypertonic). The opposite was true for hypotonic side chewing. BAL subjects were sensitive to unilateral chewing on both sides, while in IMB subjects, hypertonic side chewing did not influence performance in either males or females. Bilateral chewing elicited larger effects in BAL subjects than in IMB subjects, exceeding the values predicted from unilateral chewing in both groups. Finally, pupil size and anisocoria changes elicited by chewing were correlated with asymmetry values, independent of sex. Data confirmed the facilitation of visuospatial performance exerted by chewing. Trigeminal asymmetries modulate the chewing effects, making occlusal rebalancing an appropriate strategy to improve performance.
... Moreover, the relationship between malocclusion and cognitive impairment has become evident in the young and middle-aged. Chewing gum improves cognitive functions, such as word recall and duration of spatial working memory, in the young and middle-aged (Wilkinson et al., 2002;Baker et al., 2004;Stephens and Tunney, 2004). Malocclusion is a common dental disease in children (Lombardo et al., 2020). ...
Introduction
Occlusal disharmony induced by deteriorating oral health conditions, such as tooth loss and decreased masticatory muscle due to sarcopenia, is one of the causes of cognitive impairment. Chewing is an essential oral function for maintaining cognitive function not only in the elderly but also in young people. Malocclusion is an occlusal disharmony that commonly occurs in children. The connection between a decline in cognitive function and malocclusion in children has been shown with chronic mouth breathing, obstructive sleep apnea syndrome, and thumb/digit sucking habits. However, the mechanism of malocclusion-induced cognitive decline is not fully understood. We recently reported an association between feeding-related neuropeptides and cognitive decline in adolescent mice with activity-based anorexia. The aim of the present study was to assess the effects of malocclusion on cognitive behavior and clarify the connection between cognitive decline and hypothalamic feeding-related neuropeptides in adolescent mice with malocclusion.
Methods
Four-week-old mice were randomly assigned to the sham-operated solid diet-fed (Sham/solid), sham-operated powder diet-fed (Sham/powder), or malocclusion-operated powder diet-fed (Malocclusion/powder) group. We applied composite resin to the mandibular anterior teeth to simulate malocclusion. We evaluated cognitive behavior using a novel object recognition (NOR) test, measured hypothalamic feeding-related neuropeptide mRNA expression levels, and enumerated c-Fos-positive cells in the hypothalamus 1 month after surgery. We also evaluated the effects of central antibody administration on cognitive behavior impairment in the NOR test.
Results
The NOR indices were lower and the agouti-related peptide (AgRP) mRNA levels and number of c-Fos-positive cells were higher in the malocclusion/powder group than in the other groups. The c-Fos-positive cells were also AgRP-positive. We observed that the central administration of anti-AgRP antibody significantly increased the NOR indices.
Discussion
The present study suggests that elevated cerebral AgRP signaling contributes to malocclusion-induced cognitive decline in adolescents, and the suppression of AgRP signaling can be a new therapeutic target against cognitive decline in occlusal disharmony.
... Drugs can improve memory. Effects seem greater in poorer performers exposed to more difficult tasks, but they are modest and currently difficult to attribute to any specific biological mechanism (chewing gum can also evoke memory improvements; Wilkinson et al., 2002). A common cognitive enhancer, modafinil, directly or indirectly affects multiple transmitter systems, has varied effects on memory and other cognitive systems, and varied side-effects (Ackerman and Kanfer, 2009). ...
Scientific reductionism, the view that higher level functions can be explained by properties at some lower-level or levels, has been an assumption of nervous system analyses since the acceptance of the neuron doctrine in the late 19th century, and became a dominant experimental approach with the development of intracellular recording techniques in the mid-20th century. Subsequent refinements of electrophysiological approaches and the continual development of molecular and genetic techniques have promoted a focus on molecular and cellular mechanisms in experimental analyses and explanations of sensory, motor, and cognitive functions. Reductionist assumptions have also influenced our views of the etiology and treatment of psychopathologies, and have more recently led to claims that we can, or even should, pharmacologically enhance the normal brain. Reductionism remains an area of active debate in the philosophy of science. In neuroscience and psychology, the debate typically focuses on the mind-brain question and the mechanisms of cognition, and how or if they can be explained in neurobiological terms. However, these debates are affected by the complexity of the phenomena being considered and the difficulty of obtaining the necessary neurobiological detail. We can instead ask whether features identified in neurobiological analyses of simpler aspects in simpler nervous systems support current molecular and cellular approaches to explaining systems or behaviors. While my view is that they do not, this does not invite the opposing view prevalent in dichotomous thinking that molecular and cellular detail is irrelevant and we should focus on computations or representations. We instead need to consider how to address the long-standing dilemma of how a nervous system that ostensibly functions through discrete cell to cell communication can generate population effects across multiple spatial and temporal scales to generate behavior.
... The medicine is intended to be chewed for a certain period of time in the oral cavity before the insoluble gum base is eliminated. [5] During chewing, the medication in the gum is released into the saliva. The medicine might be absorbed via the oral mucosa or make its way to the stomach for GI absorption. ...
... rest. The chew/rest sequence was repeated two more times for a total of 300 unilateral chews.Participants in the current study completed three tests in regular order immediately before and after each intervention, as conducted in previous studies measuring the short-term effects of masticatory movement, with questionnaires given immediately after interventions23,24) . Each participant completed the test four times. ...
Objectives: This study aimed to explore the short-term effects of bilateral masticatory training using an intraoral device on memory and concentration, which is an advanced form of Gochi, compared to the unilateral form with gum.Methods: Thirty young healthy participants (age, 16–30 years) were screened and randomly assigned to one of two sequences in a crossover design. The participants assigned to sequence A (n=15) performed bilateral mastication using an intraoral device with a total of 300 taps, followed by unilateral mastication using gum with the same number of repetitions and frequency, separated by a 7-day washout period. A reverse order was used for sequence B. The primary and secondary outcomes were the digit span test result and the symbol digit modality test and the word list recallresults, respectively, which were conducted before and after each intervention.Results: Symbol digit modality test scores increased by 12.03±8.33 with bilateral mastication, which was significantly higher than that obtained with chewing gum (5.17 points;95% confidence interval: 0.99, 9.34; p<0.05). Changes in the digit span test and word list recall scores were not significantly different between the two groups. In the digit span test forward, symbol digit modality test, and word list recall test, bilateral mastication was not inferior to unilateral mastication in improving memory and concentration.Conclusions: Bilateral masticatory exercises using an intraoral device are not inferior to unilateral mastication with gum for improving memory in healthy young individuals. Further research is needed to determine the efficacy of bilateral masticatory training on cognitive function.
... Consistently, other studies reported a positive effect of gum chewing on attention in healthy volunteers (Allen & Smith, 2012;Johnson et al., 2013;Scholey et al., 2009). However, there are some contrary results (Tucha & Simpson, 2011;Wilkinson et al., 2002). Allen and Smith (2015) reported that gum chewing is associated with lengthened reaction times but fewer false alarms as the task continued, suggesting negative and positive effects on attentional performance. ...
Attention is a cognitive and behavioural process that can be affected by numerous internal and external factors. Gum chewing (GC) and repetitive motor activity (RMA) have previously been associated with improved attention. This study aimed to investigate the effects of GC and RMA on sustained attention in Attention Deficit-Hyperactivity Disorder (ADHD) A modified AX-CPT was applied to all participants (35 adults with ADHD and 30 healthy adults) for three conditions neutral, GC and RMA. There were significant differences between the groups in terms of the target responses for the neutral and the RMA conditions. A 2 (Groups) × 3 (Conditions) ANOVA revealed only a significant condition main effect. In GC and RMA, MRTs were decreased for both groups compared to the neutral condition. Both GC and RMA have improved sustained attention performance, similarly in ADHD and healthy adults so they may be used as easily accessible tools for improving attention.
... 6 Moreover, there was also an increase in the learning performance in chewers. 7 There is a significant association between teeth and cognitive function, for example, tooth loss is a risk factor of dementia. 8 Furthermore, the remaining teeth and occlusal balance have a significant correlation with cognitive function in older adults. ...
The aim of this study was to determine whether chewing gum affects cognitive function and stress relief. Sixty volunteers (mean age 23.3±3.01 years) without general or neuropsychiatric disease were recruited, and Stroop tests and stress surveys were conducted. Volunteers were administered performed a General and Emotional Stroop test with and without chewing gum, and the response time was recorded. The response time after chewing gum was significantly faster while conducting the General Stroop test. Stimulation of chewing gum may increase blood flow to the brain, which results in increased cognitive function. The response time was longer in the incongruent stimuli test compared to the congruent stimuli test, due to the effect of Stroop interference. However, when the chewing gum stimulus was introduced, the possibility of effectively reducing this effect. Stress index and response time of negative stimuli test showed weak positive correlation. This study suggests that chewing gum may play a positive role in increasing cognitive function and relieving stress.
... Par ailleurs, une collection éclectique de recherches a montré des corrélations entre la capacité en mémoire de travail, et... à peu près tout -régulation émotionnelle (Schmeichel et al., 2010), précision du tir avec un pistolet (G. Wood et al., 2016), apprentissage d'un langage informatique (Lehrer et al., 1988), performance au basketball (Buszard et al., 2017), écriture d'essais littéraires (Benton et al., 1984), suppression des pensées intrusives (Geraerts et al., 2007), modération des effets de la dépression (Noreen et al., 2019), ou encore qualité de l'improvisation au violoncelle (De Dreu et al., 2012) ; sans compter les travaux en sens inverse qui proposent que la capacité en mémoire de travail est augmentée par le fait de pratiquer l'aérobic (Pontifex et al., 2009), courir pieds nus (Alloway et al., 2016), ou mâcher du chewinggum (Wilkinson et al., 2002). Ce pattern très général de corrélations peut être vu, au choix, comme un argument en faveur de la centralité de la mémoire de travail pour l'activité cognitive , ou comme un sérieux problème de validité divergente dans la constitution d'un réseau nomologique cohérent (Cronbach & Meehl, 1955). ...
... The small increase in BP and HR observed with chewing gum compared to not chewing gum after the nitrate rich meal was contrary to our hypothesis and other clinical trials where reductions in BP are observed after a nitrate-rich meal (8). Two previous studies have, however, observed that chewing gum can result in substantial acute increases in BP and HR (27,28), including during cognitive processing (49). These studies have indicated that the increase in BP and HR are similar to those observed for exercise and is likely due to jaw muscle activity (27,28). ...
Objectives
Cardiovascular and neurocognitive responses to chewing gum have been reported, but the mechanisms are not well understood. Chewing gum after a nitrate-rich meal may upregulate the reduction of oral nitrate to nitrite and increase nitric oxide (NO), a molecule important to cardiovascular and neurocognitive health. We aimed to explore effects of chewing gum after a nitrate-rich meal on nitrate metabolism (through the enterosalivary nitrate-nitrite-NO pathway), endothelial function, blood pressure (BP), neurocognitive performance, mood and anxiety.
Methods
Twenty healthy men (n = 6) and women (n = 14) with a mean age of 48 years (range: 23–69) were recruited to a randomized controlled cross-over trial. After consumption of a nitrate-rich meal (180 mg of nitrate), we assessed the acute effects of chewing gum, compared to no gum chewing, on (i) salivary nitrate, nitrite and the nitrate reductase ratio (100 x [nitrite]/([nitrate] + [nitrite]); (ii) plasma nitrite, S-nitrosothiols and other nitroso species (RXNO); (iii) endothelial function (measured by flow mediated dilatation); (iv) BP; (v) neurocognitive performance; (vi) mood; and (vii) anxiety.
Results
Consumption of the nitrate-rich meal resulted in a significant increase in markers of nitrate metabolism. A significantly higher peak flow mediated dilatation was observed with chewing compared to no chewing (baseline adjusted mean difference: 1.10%, 95% CI: 0.06, 2.14; p = 0.038) after the nitrate-rich meal. A significant small increase in systolic BP, diastolic BP and heart rate were observed with chewing compared to no chewing after the nitrate-rich meal. The study did not observe increased oral reduction of nitrate to nitrite and NO, or improvements in neurocognitive performance, mood or anxiety with chewing compared to no chewing.
Conclusion
Chewing gum after a nitrate-rich meal resulted in an acute improvement in endothelial function and a small increase in BP but did not result in acute effects on neurocognitive function, mood or anxiety.
... Whether that was due to sympathetic nerve inhibition or parasympathetic nerve activity had been unclear; however, we concluded that it was most likely due to the predominating parasympathetic nerve activity. Furthermore, previous studies have demonstrated that mastication affects human cognitive processing, including choice reaction time [16], positive mood [17], working memory [18,19], somatosensory processing [20], motor preparation [21], and Go/No-go decision-making [22]. One factor involved in the mechanism of eye fatigue is central fatigue due to processing visual information associated with cognitive function. ...
Purpose. To investigate the effects of chewing gum and tablet candy to reduce eyestrain in healthy individuals. Materials and Methods. A double-blinded crossover trial was conducted. Forty-six healthy individuals (23 men, 23 women) between 20 and 59 years old, feeling eyestrain, were enrolled. Each 10-year age group included 12 individuals except the 30s group, which included 10 individuals. A visual task was performed on reading material displayed on a computer screen at a fixed distance for 60 min. Gum or tablet candy of two pieces were chewed for two 15-min periods starting 15 and 45 min after starting to read. Subjects chewed gum on Day 1 and tablet candy on Day 2, and vice versa. Primary outcome is as follows: subjective eye fatigue (eye tiredness, eye heaviness, blurred vision, double vision, and eye dryness) using a visual analog scale (VAS). Secondary outcomes are as follows: subjective accommodation from near and far points of accommodation measured with a D’ACOMO, spherical equivalent refraction, and eye dryness by analyzing ring break-up time (RBUT) measured with the RT-7000 Auto Ref-Topographer. Results. The VAS scores of subjective eye fatigue were not significantly changed between chewing gum and tablet candy (P=0.397-P=0.909). Those scores of eye tiredness and eye heaviness were significantly longer before and after the visual task with tablet candy (P=0.013 and P=0.025, respectively) but not with chewing gum. The changes of subjective accommodation were significantly lower after the visual task between chewing gum and candy (P=0.043). There were significant differences among each age group (20 s vs. 30 s, P=0.594; 20 s vs. 40 s, P=0.002; 20 s vs. 50 s, P=0.002). After reading, the changes of spherical equivalent refraction did not indicate a shift toward myopia (P=0.267). In the RBUT, there were no significant differences between the samples (P=0.680). Conclusions. Chewing gum helps improve the ability of the eye to focus, especially in young adults.
... Researchers reported that waking up due to mastication [7] [8] [9] results in an increase in energy consumption [10] [11]. Re-searchers also reported that performance reaction time [12] and working memory may also improve [13] [14] [15] because of mastication. Other reports involving neuro-scientific measurements indicate that mastication increases brain activity [5] and shortens cognitive processing time (e.g., the P300 wave of event-related potential after mastication [4]). ...
... Although, a number of studies have shown the vast positive impacts of chewing gum on memory, multi-tasking and mood but it has not received worldwide acceptance. 4,5 There can be a number of valid reasons for this under-rating that include funding of a number of such studies by the lucrative manufacturers of chewing gum acting as demagogues for the society, creating an impression of biasing. It can also be due to ignorance of general population regarding these studies or it can be a mere lack of evidence provided by various studies. ...
Background: Chewing gum has multidimensional effects on the body that work in harmony to improve one's abilities. The present study was aimed to focus at the authenticity of the myth that chewing gum reduces stress, elevates mood and increases concentration. Methodology: This descriptive cross-sectional survey and observational analytic study was carried at Rawalpindi Medical College, Rawalpindi over a period of 3 weeks. A total of 200 subjects participated in the study. They filled in their demographic details and self-rated their stress levels in various situations. The group was equally divided into a control and a study group. All the participants were subjected to a mental arithmetic test. The participants of the study group were provided with a gum during their examination. A comparison of the marks scored was done. Results: Out of the entire group only 13.3% were non-chewers whereas 50% replied that they chewed gum 'sometimes'. Majority of the people felt mild, moderate and severe stress in general, while in college and during examination respectively. A large number of subjects chewed gum for the reason that it makes them feel elated (43.3%). In the mental arithmetic test, the non-chewer group scored more than the chewer group with a highly significant statistical difference (p=0.001). Conclusion: Chewing gum has no or minimal role in reducing stress. However, as it cherishes ones' mood, it can be chewed to get rid of the acute anxiety states faced during various stressful conditions. Nevertheless, the study strongly denounces the concept that chewing gum enhances ones attention and cognition.
... Based on these findings, the authors speculate that these two behaviors may produce similar changes to cognitive processing. Although connections between gum chewing and cognition are mixed (Allen & Smith, 2011), evidence suggests that working memory performance can be enhanced by this behavior (e.g., Wilkinson, Scholey, & Wesnes, 2002;Stevens & Tunney, 2004;Hirano et al., 2008). This is noteworthy given previous research has suggested that, by cooling the brain, yawns could enhance mental processing efficiency on tasks evoking working memory (i.e., vigilance) (Gallup & Gallup, 2007). ...
... In the case of nicotine a complex interaction with attention and memory occurs [12]- [14] while caffeine reduces tiredness [15]- [17] Even common, traditional, and unregulated herbs and spices, such as sage, can improve memory and mood through chemical effects [18] .Chewing gums may also affect memory probably by heightening arousal or increasing blood sugar level. [19] Neurotechnical Enhancement: ...
... Fig. 7 provides and overview of the spectral power and topography of ChRE in relation to craniotomy defects. Mastication has also been described to have effects on cognitive performance in healthy volunteers (Wilkinson et al., 2002;Smith, 2009;Onyper et al., 2011;Tucha and Simpson, 2011). Endogenous brain stimulation by ChRE might be a likely candidate to explain the modified cognitive performances of healthy volunteers after mastication, which up to now have been attributed to unspecific arousal effects. ...
In this work, the propagation of electric potentials from source to measurement points was investigated with three finite element method (FEM) models which were based on magnetic resonance imaging (MRI) data sets of increasing spatial resolution. The spatial observation scales of the electrophysiological imaging modalities of electroencephalography (EEG), micro EEG (μEEG), electrocorticography (ECoG) and micro ECoG (μECoG) were modeled. The Leitmotiv of this work is to understand how neuronal and other sources are reflected in high-resolution multi-scale electrophysiological neuroimaging. In the process, anatomical details like foramina, craniotomy defects and cortical depth of modeled dipoles were specifically addressed.
In the first part of this work, it was investigated how electrical potentials propagate from outside of the skull into the brain. This approach is based on the observation that in subdurally implanted epilepsy patients electromyographic (EMG) artifacts are measurable within the skull with ECoG electrodes. To simulate the propagation of those artifacts from the temporal muscle to the ECoG electrodes, we created an individualized FEM model based on MRI data recorded before and after the electrode implantation. Craniotomy defects and highly insulating silicon ECoG grid were implemented. By relating simulation results and measurements in epilepsy patients, it was possible to show that propagation of EMG artifacts into the brain is indeed facilitated by the presence of craniotomy defects, but that even in their absence, the artifacts would still generate 0.11V/m.
In the second part of this work, propagation of cortical potentials to the surface of the head was investigated. To this end, naturally present skull foramina were modeled. Because the spatial resolution of standard 1.5 Tesla (T) diagnostic MRI is not sufficient to resolve skull foramina induced by highly conductive blood vessels which might influence electric propagation, 7T MRI measurements were used to create for the first time a ultra-high resolution FEM model. EEG and μEEG electrodes were added to it. The results of the simulations show that foramina located close to the electrodes have a dual effect. They increase the amplitudes of potentials measured on the surface of the head and distort the electrical field into their direction. The second effect could only be measured using μEEG, the spatial resolution of EEG being to low to capture the electric field shift. This finding highlights the usefulness of spatial multiscale approaches.
After having simulated EEG, μEEG, and ECoG measurements, the last part of this work investigates spatially highly resolved μECoG measurements. As μECoG is not yet medically established, no human measurements exist for comparison. We therefore created a Göttingen minipig brain FEM model. Comparison of in vivo measurements and simulations show that, in Göttingen minipigs, dipolar cortical activity generated at a depth of 0.6mm best fits the spatial profiles measured by μECoG.
In summary the present thesis shows that (i) placement of cortical dipoles at realistic depths and (ii) incorporation of individual skull anatomy, down to millimeter wide foramina, are necessary for realistic multiscale modeling both of electrophysiological signal propagation to and from the brain.
... It significantly increases bilateral middle cerebral artery blood velocity and oxygen levels [30,31]. Moreover, it has been shown to increase heart rate and improve memory function possibly due to upregulated delivery of metabolic substrates to the brain (Wilkinson, Scholey and Wesnes, 2002). The movement of masticatory muscles may be also considered a physical activity constituting a mild form of exercise which is a well-established modulator of not only AHN but cognitive health in general [32,33]. ...
BACKGROUND
Decreased mastication due to edentulism in both humans and animals have a negative impact on brain function and cognition. Human populations have shown a close association between masticatory function, cognitive status and age-related neurodegeneration in the elderly. Evidence shows that mastication during tasks may have an acute positive impact on normal cognitive function, such as sustained attention. However, there is a lack of evidence showing the long-term effects of changes in habitual masticatory behaviour on cognition.
OBJECTIVE
To investigate the impact of a 3-month mastication intervention on cognitive function in healthy older adults.
METHODS
53 participants aged 45–70 years old were required to chew mint-flavoured sugar free chewing gum for 10 minutes, 3 times a day over 3 months. Pattern separation and recognition memory was measured using the Mnemonic Similarity Task. Questionnaires were administered to measure changes in mood, anxiety, and sleep quality.
RESULTS
Extended periods of mastication gave rise to a significant improvement in recognition memory compared to a non-chewing control group.
CONCLUSION
With an ageing population, non-medical interventions are imperative to delay age-related cognitive decline. Further work needs to be carried out in larger populations to validate the findings in this study and elucidate potential mechanisms.
... Hollingworth [3] in 1939 demonstrated the relationship between mastication and cognitive functions through elec- troencephalography and stated that there is an increase in performance of cognitive function during mastication. In 2002, Wilkinson et al. [4] carried out an experimen- tal study between chewing and non-chewing groups, and found an increase in episodic, spatial and numeric work- ing memory in chewing group when compared with that of the non-chewing control group. Numerous such studies have been carried out which associate the reduced number of residual teeth and decreased use of dentures to cognitive deficits [5,6]. ...
Mastication as we all know has always been related to its primary function of digestion, but little do we know that it produces an enhancing effect on general health, especially the cognitive performance related aspects of memory. Recent studies have shown its association with activation of various brain regions, however little is known about its effects on neuronal activity in these specified regions. According to the enormous evidences collected so far, mastication has proved to be effective in conducting huge amount of sensory information to the brain, and maintaining learning and memory functions of hippocampus. Therefore it is essential that we maintain normal occlusion and preserve the masticatory function as long as possible to prevent the attenuation of hippocampus, caused by occlusal disharmony and reduced mastication. We provide an overview on how mastication activates various cortical areas of the brain and how an increase in the cerebral blood oxygen level of hippocampus and prefrontal cortex (PFC) accentuates the learning and memory process. We also justify why maintaining and establishing a normal occlusion is important from neurological point of view.
... Wilkinson et al. found that heart-rate was increased when chewing gum compared with when participants did not chew gum. They also observed improvements in cognitive function and suggested that mastication may have increased regional cerebral blood flow and increased insulin release [116]. ...
... So far, it has been reported that gum chewing stabilizes the heart rate (1), and so it is thought that competition performance will be improved. In addition, it has been reported that gum chewing contributes to alertness (2)(3)(4) and shortens selection reaction time (5), and increases working memory (6)(7)(8). It has also been reported that P300 of event-related potential is shortened by gum chewing (9). ...
In the present study, we examined the cognitive function during mastication of lemon flavored gum, which is said to enhance mind flavor gum and especially cerebral blood flow. Nine healthy subjects (8 female and a male) participated in this study. Subjects chewed the gum for 3 min after fasting for 2 hours and conducted a stoop test while continuing chewing as it was. At the end of all answers, gum chewing ended. The response time in the Stroop test was used as an indicator of cognitive function. We sat the three conditions (Lemon flavored gum, Mint flavored gum, Without gum chewing). There was no significant difference in reaction time between mint flavor gum chewing and without gum chewing (p > 0.05). However, the response time during chewing gum with lemon flavor was significant slower than the conditions with mint without gum and with without gum chewing (p < 0.05, in both). From the results of the present study, it was suggested that the response time delay of the Stroop test during chewing of lemon-flavored gum was observed, suggesting temporary decay of cognitive function during lemon-flavored gum chewing. It is suggested that lemon- flavored chewing gum forces the brain to act loadfully, resulting in a temporary decrease in cognitive function.
Objectives:
Chewing gum has been shown to improve aspects of cognition and mood with sustained attention being particularly receptive to the effects of chewing. Chewing gum may also be a useful vehicle for administering functional ingredients. The herbal extract Rhodiola rosea and certain B-vitamins have previously been shown to improve aspects of cognition and subjective state, but their combined effects have not been studied to date.
Methods:
The current randomised, placebo-controlled, double-blind, balanced crossover study compared the effects of a functional gum containing Rhodiola rosea and B-vitamins to flavour-matched regular chewing gum and a flavour-matched placebo. Thirty-six healthy young participants completed measures of attention and mood at baseline, during chewing, and 1-h after chewing.
Results:
Chewing both functional and regular gum was shown to reduce errors on a digit vigilance task compared to placebo irrespective of whether measured during or after chewing. There were no benefits to adding functional ingredients to the gum.
Discussion:
Future chewing research should consider different formats of placebo. Sex differences in response to chewing and the impact of rate and intensity of chewing should also be explored.
Trial registration:
ClinicalTrials.gov identifier: NCT05544500.
Chewing gums are the type of mobile drug delivery systems. It is useful by means of administering drugs either locally or systemically through, the oral cavity. The treated chewing gum has through the times gained adding acceptance as a medicine delivery system. As compare to that chewable tablets treated epoxies aren't supposed to be swallowed and it can be removed from the point of operation without resort to invasive means and treated biting gum. MCG is solid, single cure medication. The end of this review is to gives an overview of gum composition, manufacturing process, and characterization. Due to the failure of studies concerning the evaluation of the mechanical parcels of MCGs, lesser effect was placed on the available performance tests and procedures for the estimation of their mechanical and textural parcels. It can be used either for original (mucosal) treatment of mouth complaint or for systemic (transmucosal) delivery by direct intra oral immersion through the buccal mucosa.
Background:
Mastication improves cognitive function by activating cerebral cortical activity, and it is important to demonstrate the cognitive effects of masticatory training using a variety of different interventions.
Objective:
This study aimed to evaluate the effects of masticatory exercise on cognitive function in healthy older adults living in the community.
Methods:
For six weeks, twelve participants performed a masticatory exercise using a NOSICK exerciser device, and thirteen subjects performed daily life without masticatory exercises. Trail Making Test, Digit Span Test, and Stroop test were used to measure the cognitive function.
Results:
The participants in the experimental group showed significant improvements in TMT-A/B (p= 0.001 and 0.004), DST-forward (p= 0.001), and ST-word (p= 0.001). The effect sizes after the intervention were calculated as (1.2 and 0.8) for TMT-A/B, (0.8 and 0.2) for Digit Span Test forward/backward, and (0.6 and 0.2) for Stroop test color/word.
Conclusions:
We suggest that the masticatory exercises improve cognitive function in healthy older adults. Therefore, masticatory exercises can be used as a therapeutic exercise during cognitive rehabilitation.
Innovative flavors are trends in the chewing gums market. Nine formulation on gums made with different kinds of yerba mate and flavors were evaluated. A time‐intensity test was carried out to estimate how long the taste lasted. The MDPREF PCA graph showed that de first two dimensions explained 45.42% of the total variance. Three groups were noted: samples elaborated with chamomile (forced and aged yerba mate); samples with toasted/chamomile and natural/green apple; and all the samples flavored with orange and flavored with green apple (forced aged and toasted). Yerba mate forced aged with orange and green apple flavors were preferred by the consumers. The total duration of the stimulus was just over 5 min. This study suggests that the combination of yerba mate with other flavors has potential for use in chewing gums, however, it needs to be optimized to improve the acceptance and the duration of the flavor.
Background
Several studies have examined the relationship between cognition and oral health in older populations. To further understand this relationship, we examined the associations between cognitive function, chewing capacity and the number of teeth present in community‐dwelling older males in Australia.
Methods
Data were obtained from cross‐sectional analysis of fourth wave of the Concord Health and Ageing in Men Project (CHAMP). Participants were 369 community‐dwelling males aged 78 years or over. Cognitive function was measured utilising the Mini‐Mental State Examination (MMSE). Chewing capacity was determined on ability to chew food items of different textures, and oral health data were collected. Ordinal regression was used to analyse associations between MMSE (four categories) and chewing capacity and number of natural teeth present.
Results
Overall, 67.5% of participants reported that they could chew all 11 listed food items. Participants with fewer than 20 teeth were statistically significantly more likely to have cognitive impairment (unadjusted odds ratio (OR) 1.87; 95% confidence interval (CI) 1.25‐2.79, adjusted OR 1.62; 95% CI 1.07‐2.43). Participants with limited chewing capacity were also more likely to have cognitive impairment (unadjusted OR 1.91; 95% CI 1.25‐2.94, adjusted OR 1.61; 95% CI 1.03‐2.49).
Conclusions
This study suggests either that older men with fewer than 20 natural teeth and those with limited chewing capacity are more likely to have an associated cognitive impairment or that those with cognitive impairment are more likely to have fewer teeth and limited chewing capacity. Further longitudinal studies should clarify these relationships.
Aim:
As our society ages, the number of people living with dementia also steadily increases. Some work has focused on masticatory behaviour as a form of daily health care that could help prevent cognitive impairment and dementia. However, it is not yet clear how masticatory behaviour influences various cognitive functions. Therefore, the purpose of this study was to examine the effect of masticatory behaviour on the decline of generalized attention, an important cognitive function.
Methods:
Participants were 35 healthy, dentulous individuals without stomatognathic abnormalities (24 men, 11 women; mean age: 56.8 ± 4.8 years). All participants completed three interventions: mastication, foot-stepping, and none (control). Pre- and post-intervention measures of generalized attention were measured by using neuropsychological tests to examine general attention; the results were then compared. Simultaneously, during the generalized attention task, the functional activity of the prefrontal cortex was observed on functional near-infrared spectroscopy.
Results:
Response time of generalized attention improved in both the masticatory and foot-stepping interventions. There was a transient increase in oxyhaemoglobin activity in the right and left prefrontal cortices in the masticatory intervention.
Conclusions:
Masticatory behaviour may be involved in a partial improvement of generalized attention and may induce prefrontal cortex activity in middle-aged and older adults.
It has often been suggested that verbal short-term memory, the ability to maintain verbal information for a brief period of time, is based on the upload of to-be-remembered material into passive, dedicated, information stores. Alternatively, it has been claimed that all information is remembered but that access to it gets obstructed because of interference by subsequent similar material. The aim of this chapter is to present both approaches and to examine the viability of a different, perceptual-gestural, view of information buffering over the short term. This approach conceptualizes verbal short-term storage as an active process that emerges from, and is defined by, the recruitment of receptive and (speech) productive mechanisms. Experimental results actually suggest an active involvement of productive mechanisms. These experiments also cast doubt on the proposal that forgetting occurs because of interference by similar content. Another experiment expands upon this challenge of the interference-based view by showing that a temporary lesion of a brain area involved in speech planning (Broca’s area) affects verbal short-term memory performance in the absence of any additional potentially interfering verbal input. Further, challenging the store-based view, the virtual lesion of Broca’s area also attenuated the phonological similarity effect, a hallmark effect of the function of the hypothetical language-independent store. Finally, based on further experiments, it is concluded that only the perceptual-gestural approach can offer an account of presentation-type-based differences in verbal list recall that goes beyond a redescription of the observed effects.
Background
There is increasing evidence of causal links between poor mastication and cognitive impairment, but possible effects of dietary hardness, which clearly affects mastication, on cognitive function is unknown.
Objective
We investigated the hypothesis that hardness of the habitual diet would be associated with cognitive function among older Japanese adults.
Methods
The subjects of this cross‐sectional study were 635 Japanese community‐dwelling people aged 69‐71 years. The masticatory muscle activity required for the habitual diet was used to determine dietary hardness. Consumption of 38 foods was assessed by a validated, brief‐type, self‐administered diet history questionnaire. A published database was then used to estimate the masticatory muscle activity involved in the ingestion of these foods. The Japanese version of the Montreal Cognitive Assessment (MoCA‐J) was used for the measurement of cognitive function.
Results
The principal contributors to dietary hardness were cooked rice (28.0%), green leafy vegetables (5.1%), dried fish (4.9%), and pork and beef (4.6%). There was a positive association between dietary hardness and MoCA‐J score that was robust to adjustment for potential confounders (MoCA‐J score per 100‐unit increase in dietary hardness: β=0.83 [95% CI: 0.08, 1.59], P=0.03). These results did not change materially even after exclusion of subjects who reported substantial changes in their diet for any reason (β=0.94 [95% CI: 0.02, 1.86], P=0.04).
Conclusion
This preliminary cross‐sectional study suggests that dietary hardness might have a beneficial effect on cognitive function in older Japanese people. Further prospective studies with more accurate measurements are needed to confirm this finding.
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Rough notes of a clinical oral presentation of our comprehensive published review article.
PLEASE download and CITE the published version as a reference. The published review is downloadable below.
HS Bracha MD. .............................................................................
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INTENSE, PROLONGED JAW CLENCHING; it can be clinically observed during fear or rage in developmentally disabled individuals (and may be mistaken for dystonia). displays of jaw clenching can also be seen in preverbal healthy toddlers, which may also be a manifestation of fear or rage in the preverbal period. such clench- ing displays, both in patients with mental retardation and in healthy preverbal toddlers, precdict imminent actual bit- ing of others. ..................>
ALSO, ANECDOTALLY, INFORMATION FROM EMERGENCY DEPARTMENTS suggests that physically assaulted individuals, and especially sexually assaulted individuals, may use biting as a means of self-defense.22 This may even be relevant in the assessment of individuals presenting in emergency departments with severe human bites, especially to the head and neck.
TEMPORAL-LIMBIC STRUCTURES AND JAW CLENCHING
We posit a second role for jaw clenching in the distressed/anxious individuals based on recent literature3.29 We hypothesize that jaw clenching increases the blood flow to anterior temporal lobe structures during acute activation of the limbic fear circuits. Jaw clenching may increase the blood flow to the hemodynamically vulnerable temporal lobe structures especially the hippocampus by pumping blood through the temporal bone emissary veins, thus enhancing immediate memory retrieval and night time memory consolidation and also conferring survival advantage during activation of the limbic fear-circuits in expect tion of situations requiring the freeze, flight, fight, fright acute fear response.18,19,30 This is consistent with new research, 29,31-33 which demonstrates a possible beneficial affect of masticatory movements (eg, non-nutritive chewing) on both hippocampal function and hippocampal structure.
Based on pioneering work by Dr Andrew Gallup and associates which they concluded that yawning causes 'cooling of the brain', we propose that another way to produce such emmisery vein blood flow to the temporal lobe is yawning.). INTENTIONAL YAWNING may suppress the urge to clench.
And remind people of the habit of police investigators (see Hollywood movies) to bite on a toothpick while concentrating and which prevents clenching-induced damage to the teeth. Tell man that women find biting a wooden toothpick sexually attractive.
And strongly recommend non-nutritive gum such as SPRY green tea flavored dental defense system gum to reduce systemic inflammation and minimize contact between upper and lower teeth.
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..... IMPLICATIONS FOR PSYCHIATRIC DIAGNOSIS.
Assessment Implication: “Hard to Hide” and “Hard to Fake” Physical Signs of Stress and Anxiety In addition to shifting focus from disorders to spec- trums, Psychiatry needs to include a larger number of physical examination signs in the “Associated Physical Examination Findings” sec tions of the DSM text and possiblly as subcriteria for the diagnoses of some disorders. Assessments of anxiety spectrum disorders currently depends almost exclusively on retrospective self-report. Extensive psychometric literature has demonstrated that paper and pencil instruments (particularly questionnaires and also structured interviews) for trait anxiety and recent subjective distress can be highly vulnerable to both over-reporting35-37 and under-reporting.37-42 This diminishes both the positive predictive value and the negative predictive value of questionnaires and structured interviews. We posit that easily observable physical signs, such as incisor tooth wear, may augment the clini- cal assessment of fear-circuitry disorders such as posttraumatic stress disorder (PTSD).......
. In clinical psychiatric settings, objective physical “hard to hide” signs of stress-induced and fear-circuitry dis- orders are also rare. Wear of the incisors’ enamel invari- ably results from chronic grinding and may be one such hard to hide sign. Clinicians practicing in settings where individuals tend to under-report symptoms due to stigma, cultural, or other reasons, may especially benefit from hard-to-hide indica- tors of under-reported anxiety. Self-imposed cultural barriers of access to men- tal healthcare may also exist in other “bushido” (warrior) male cultures. The United States Armed Forces active duty-enlisted personnel appears to be another American male culture that under-reports emotional distress due to stigma and deep-rooted beliefs about masculinity. This can impede clinical assessment (eg, suicide risk), early intervention, and primary prevention......
....Furthermore, incisor tooth wear is also a “hard- to-fake” indicator of anxiety. Such objective signs are much needed in the clinical armamentarium in settings, such as litigation and compensation and substance abuse treatment centers where patients may over-report anxiety symptoms. Assessment of observable signs of clenching-grinding can be easily incorporated into the examination of the anxious patient in psychiatric medicine and general medi- cal settings, as well as in substance abuse settings. Even before tooth wear is noted in incisors, bilat- eral hypertrophy and tenderness of the masseter and especially the temporalis muscle can often be identi- fied by inspection and palpation in acutely distressed patients unaware of their clenching.
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Please download and please cite the full text tutorial review article that expands on this lecture. It is below. Also since you read this presentation all the way to the end you obviously found it useful So please recommend it. You will help your friends and colleagues notice it.
The impact of chewing gum on fasting appetite or meal intake has not been studied. We tested the hypothesis that chewing gum would decrease lunch intake after a controlled breakfast, and reduce hunger in fasting and fed states. Seventeen males and sixteen females (21.4 ± 6.3y, BMI 23.8 ± 2.7 kg/m²) participated in a randomized crossover study in which subjects chewed sugar-free gum a total of one hour on the test day (GC), and did not chew gum on a control day (NG). The 1 h of gum chewing included 20 min while fasting, and two 20-min sessions between breakfast and lunch. Subjects rated their appetite and mood on visual analog scales. After completing the fasting measures, subjects consumed a breakfast shake containing 30% of their measured resting energy expenditure. Three hours later they consumed an ad libitum lunch with water. Fasting ratings of hunger were lower in GC than NG (t = 2.66, p = 0.01). Subjects consumed significantly less pasta (41 g, 68 kcals, t = 2.32, p = 0.03) during GC than NG. In conclusion, gum chewing decreased fasting hunger ratings and lunch energy consumed. Chewing gum may be a useful tool impacting energy balance in this population. Longer studies, especially in other populations, will be required.
Chewing gum is one of the very popular oral confectionary products. It is a potentially useful means of administering drugs either locally or systematically via, the oral cavity. The medicated chewing gum (anti-smoking chewing gum) has through the recent years gained increasing acceptance as a drug delivery system. The use of the chewing gums is also suggested for other disorders like the gingivitis, plaque, flow of saliva, as a mouth freshener and prescribed mostly by dental physicians. It is having a wider acceptability with the patients and that is why its popularity is increasing. From 3,000years the smoking habit has been the favorite pass time of people from different civilizations. People still posses this habit and the intake of NICOTINE is increasing in different forms like the cigarette, pure tobacco and cigar. Due to the increasing intake of tobacco, there is need for the development of the novel drug delivery systems for the smoking cessation. This review tries to explain the chewing gum as a dosage form and ASTS, also popularly known as the nicotine replacement therapy, considering the application of the gum to it and its other components which may be great help in future for smoking cessation.
It is suggested that mastication stimulates the brain and accelerates its energy-consuming metabolism. This study was designed to determine its effects on regional cerebral blood flow (rCBF) using xenon-enhanced computed tomography (Xe-CT). Seven male volunteers, aged 24-57 years, inhaled 30% xenon in a 4 minutes wash-in and 4 minutes wash-out protocol. CT was scanned every 54.5 seconds. The subjects were instructed to chew a gum continuously at a rate of 1 bite per second except at the time of CT scanning (5.5 seconds). A second CBF was done 20 minutes later. Subtraction (mastication-baseline) maps were created. CT images were taken at three levels so as to include the cortex, basal ganglia, limbic system, brainstem and cerebellum. The results demonstrated a significant rCBF increase in the fronto-temporal cortex, caudate nucleus, thalamus and minor increase in the rolandic areas, insula, cingulate and cerebellum. Further studies are needed to validate the clinical significance of these findings.
It is known that glucose administration is capable of improving performance on tests of declarative verbal memory and non-mnemonic tasks requiring high "mental effort". At the same time, cognitively demanding tasks are associated with elevated heart rate, a response that could feasibly be part of a physiological mechanism serving to increase the delivery of glucose to active brain substrates.
The present placebo-controlled, double-blind, balanced, crossover study examined the interaction between glucose administration, cognitive performance and heart rate during three tasks of differing mental demand and somatically-matched control tasks.
The effects of a glucose drink on participants' performance on two serial subtraction tasks (Serial Threes and Serial Sevens) and a Word Retrieval (Verbal Fluency) task were assessed. Heart rates were monitored throughout the experiment, and participants rated each task in terms of its perceived mental demand.
Serial Sevens was rated as the most mentally demanding task, followed by Word Retrieval, then Serial Threes. Glucose consumption significantly improved performance on Serial Sevens, with a trend for improved performance on Word Retrieval. Both Serial Sevens and Serial Threes were associated with significant heart rate elevation above that seen in somatically matched control tasks (ruling out the possibility that accelerated heart rate was due to peripheral mechanisms alone). Unexpectedly, participants in the glucose condition had higher heart rates during cognitive processing. Additionally, individuals whose baseline heart rates were below the median performed better on Serial Threes and Serial Sevens.
We suggest that supplemental glucose preferentially targets tasks with a relatively high cognitive load, which itself (through unknown mechanisms) mobilises physiological reserves as part of a natural response to such tasks. Furthermore, baseline heart rate and responses to cognitive demand and glucose administration may represent important physiological individual differences.
Chronic administration of extracts from the leaves of the tree Ginkgo biloba is known to improve aspects of cognitive performance. However, little is known about the effects of acute doses of Ginkgo on coherent cognitive domains. Recent factor analysis of test measures from subtasks of the Cognitive Drug Research (CDR) computerised assessment battery has revealed that four primary cognitive 'factors' corresponding to speed of attention, accuracy of attention, speed of memory and quality of memory can be useful to describe cognitive function changes.
The present study aimed at assessing whether acute administration of Ginkgo biloba had any consistent effect on the four CDR factors.
The study utilised a placebo-controlled, multi-dose, double-blind, balanced, crossover design. Twenty participants received 120 mg, 240 mg and 360 mg of a standardised extract of Ginkgo (GK501, Pharmaton, SA) or a matching placebo. Cognitive performance was assessed using the CDR computerised test battery immediately prior to dosing and at 1, 2.5, 4 and 6 h thereafter. The primary outcome measures were the four aspects of cognitive performance, which have previously been derived by factor analysis of CDR subtests.
Compared with the placebo, administration of Ginkgo produced a number of significant changes on the performance measures. The most striking of these was a dose-dependent improvement of the 'speed of attention' factor following both 240 mg and 360 mg of the extract, which was evident at 2.5 h and was still present at 6 h. Additionally, there were a number of time- and dose-specific changes (both positive and negative) in performance of the other factors.
We conclude that acute administration of Ginkgo biloba is capable of producing a sustained improvement in attention in healthy young volunteers.
Although the cardiovascular effects of exercise have been extensively investigated in man, little attention has been paid to such responses to jaw muscle activity. The aim here was to investigate the general cardiovascular effects of chewing activity in a single-blind, cross-over design. Ten healthy individuals performed one of the following chewing tasks in four separate sessions: chewing a very hard gum, chewing a moderately hard gum, chewing a soft gum, and "empty chewing" without a bolus. Unilateral chewing of gum or empty chewing was performed for 20 min on the participant's most convenient chewing side at a constant rate of 80 cycles/min. In each session, heart rate and arterial blood pressure were recorded together with electromyographic activity in the masseter and anterior temporalis muscles on the chewing side. Ratings of perceived masticatory fatigue were recorded with visual analogue scales. The heart rate and blood pressure were significantly increased (ANOVA; p < or= 0.01) during the chewing tasks and the increases were, in parallel with the muscle activity, more pronounced the harder the gum. With the very hard gum, heart rate increased by up to 11 beats/min, the systolic blood pressure was 14 mmHg (1.9kPa) higher, and the diastolic blood pressure was 11 mmHg (1.5kPa) higher. The perceived fatigue was proportional to the level of muscle activity. After 10 min of recovery from exercise, heart rate and arterial blood pressures were slightly but still significantly elevated. The results demonstrate that chewing is associated with general circulatory effects proportional to the bolus resistance.
Previous research has identified that glucose administration can enhance cognitive performance, especially during more intense cognitive processing. There appears to be a reciprocal relationship between falling glucose levels and cognitive performance, particularly under conditions of cognitive demand. The present placebo-controlled, double-blind, balanced, crossover study examined the possibility that a high cognitive load may produce changes in blood glucose levels. A secondary aim was to examine the effects of glucose on tasks of varying cognitive demand load. The effects of a glucose drink on participants' performance of a serial subtraction task (computerised Serial Sevens), a somatically matched control task (key-pressing), a short interval Word Memory task and a Word Retrieval (Verbal Fluency) task were assessed. The change in blood glucose during the demanding computerised Serial Sevens was compared to the change occurring during the key-pressing control. Glucose consumption significantly improved performance on Serial Sevens, with a trend for improved performance on Word Retrieval and no effect on the Word Memory task. Compared with the control task, Serial Sevens resulted in a significant reduction in blood glucose in both drink conditions. This accelerated decay was significantly greater following glucose than placebo. It is suggested that the amount of cognitive load associated with task performance is an index of its sensitivity to enhancement by glucose. Furthermore, a period of intense cognitive processing leads to a measurable decrease in levels of peripherally measured blood glucose, which may be linked to increased neural energy expenditure. However, the relative contribution of central and peripheral (e.g. cardiac) activity to this effect has yet to be determined.