Camilla M Hoyos

• MPH PhD
• Research Leader at Woolcock Institute of Medical Research

Study Objectives While alterations in rest-activity rhythms are common in older adults ‘at risk’ for dementia, it is unclear how rest-activity rhythms relate to underlying brain integrity. Methods Older adults aged > 50 years (n=143, mean age=67) with subjective and/or objective cognitive impairment underwent MRI scanning and 14-days of actigraphy...

Background Recent growth in the functionality and use of technology has prompted an increased interest in the potential for remote or decentralised clinical trials in dementia. There are many potential benefits associated with decentralised medication trials, but the field is currently lacking specific recommendations for their delivery in the deme...

Insomnia is common in adolescents with associated negative health consequences. This systematic review and meta‐analysis assessed the effect of cognitive behavioural therapy for insomnia interventions on insomnia symptoms and subjective sleep quality in adolescents aged 10–19 years. Key electronic databases, including CINAHL, Embase, MEDLINE, PsycI...

Background Obstructive sleep apnea (OSA) is highly prevalent among older adults and has been associated with cognitive decline and dementia risk. The suitability of screening tools for detecting OSA in memory clinic settings is unclear. Objective To evaluate the utility and validity of the STOP-Bang questionnaire (SBQ) and pulse oximeter as a scre...

Purpose of review Cannabis sativa and constituent cannabinoids are in widespread use for the treatment of sleep disorders where many patients desire pharmacotherapy. Previous reviews highlight a lack of high-quality evidence to support the efficacy and long-term safety of cannabinoids in various conditions. We aim to provide an update of recent ori...

Introduction Obstructive sleep apnea (OSA) is an emerging risk factor for cognitive decline. Sleep clinics are well positioned to screen for early biomarkers. We will evaluate the feasibility of cognitive testing and neurodegenerative blood-biomarker collection in a sleep clinic. Methods Males and females (>40 years) referred for polysomnography o...

Introduction Insomnia affects over 40% of older adults, impacting on their health and quality of life, but is often untreated. This study investigated the acceptability of digital therapy for insomnia in older adults using a mixed-methods approach. Method Eligible (age≥60, ISI≥10) respondents participated in an online survey exploring their smartp...

Introduction Light therapy is a non-pharmacological intervention for circadian and sleep disorders. However, there is limited evidence about the effect on electroencephalographic (EEG) sleep in older individuals with sleep disturbance. Methods Twelve participants (8 female; mean ± SD age, 65.6 ± 8.7 years) with self-reported poor sleep completed t...

During the COVID-19 pandemic, studies reported that restricted living conditions were associated with worse subjective sleep quality. This effect might have been caused by reduced light exposure during lockdowns. We investigated light exposure levels, subjective and objective sleep and physical activity levels in older adults during restricted and...

Melatonin has multiple proposed therapeutic benefits including antioxidant properties, circadian rhythm synchronisation and sleep promotion. Since these areas are also recognised risk factors for dementia, melatonin has been hypothesised to slow cognitive decline in older adults. Participants with Mild Cognitive Impairment (MCI) were recruited from...

Objectives The Action To promote brain HEalth iN Adults study aimed to determine the feasibility and applicability of recruitment using home blood pressure (BP) monitoring, routine blood biochemistry and videoconference measures of cognition, in adults at high risk of dementia. Design A decentralised double-blind, placebo-controlled, randomised fe...

This year the rankings really didn't change at the top of the list but there have been some notable movers (Sleep Medicine Clinics: a review journal is up to 3.0). The sugar hit from Covid (plus cleaning up of the predatory journals which substantially increased IFs across many health related journals) has really dissipated now and that also includ...

Cannabis and its major constituents, Δ⁹-tetrahydrocannabinol (THC) and cannabidiol (CBD), are being widely used to treat sleep disturbances. However, THC can cause acute cognitive and psychomotor impairment and there are concerns that driving and workplace safety might be compromised the day after evening use. Here, we examined possible ‘next day’...

Introduction Insomnia is common in older adults with mild cognitive impairment (MCI) and predicts future cognitive decline. Cognitive Behavioural Therapy for insomnia (CBT-I) is the first-line treatment for insomnia but is often unavailable. We tested the feasibility of a randomised controlled trial comparing 12-weeks of digital CBT-I vs wait-liste...

Introduction Cannabidiol (CBD) is a non-intoxicating cannabinoid which Australian regulators (TGA) have proposed down-scheduling to an over-the-counter pharmacist-only medicine pending positive efficacy trials. This trial compared the effect of 50mg and 100mg/day of an oral capsule CBD medicine with placebo over 8 weeks on insomnia symptoms, stress...

Point‐of‐collection testing (POCT) devices are widely used in roadside and workplace drug testing to identify recent cannabis use by measuring the presence of Δ ⁹ ‐tetrahydrocannabinol (THC) in oral fluid (OF). However, the performance of POCT devices with oral medicinal cannabis products remains poorly described. In a randomised, double‐blinded, c...

Background Sleep is a physiological state involving a dynamic autonomic profile that is ideal for detecting subtle changes in autonomic nervous system functioning. The current study sought to determine if heart rate variability (HRV) during different periods of sleep is impaired in older adults with early‐onset (EOD), late‐onset (LOD), and no histo...

Background Circadian disturbances are a common occurrence in older adult population but are more prevalent in people with dementia. For some individuals, these occurrences begin many years prior to the onset of clinical symptoms and have been suggested as a potential risk factor. As light is the primary synchroniser of the circadian system, the cur...

Background The prevalence of sleep disturbances increases in ageing and may further increase in neurodegeneration. In a memory and cognition (MC) clinic setting, our study aims to: 1) determine the rates of various sleep disturbances including obstructive sleep apnoea (OSA), short and long sleep duration, insomnia, sleep quality, and rapid eye move...

Background Melatonin has multiple proposed therapeutic benefits including antioxidant properties, circadian rhythm synchronisation and sleep promotion. Since these areas are also recognised risk factors for dementia, melatonin has been hypothesised to slow cognitive decline in older adults. Method Participants with Mild Cognitive Impairment (MCI)...

Background Reduced heart rate variability (HRV) can be an early sign of autonomic dysfunction in neurodegenerative diseases, and may be related to brain dysfunction in the central autonomic network (CAN). As yet, such autonomic dysfunction has not been examined during sleep – which is an ideal physiological state to study brain‐heart interaction as...

Background Rest-activity rhythm disturbance is common in older adults ‘at risk’ for dementia. This may be an early marker of underlying disease pathology and risk of future decline. However, our understanding of how rest-activity rhythm relates to brain integrity remains unclear. Methods This study used vertex-wise analyses to examine the associat...

Introduction This study assessed whether the addition of CPAP during weight loss would enhance cardiometabolic health improvements in patients with obesity and OSA. Methods Patients with overweight or obesity, pre-diabetes and moderate-severe OSA were randomised to receive CPAP therapy with a weight loss programme (CPAP+WL) or a weight loss progra...

Epidemiologic studies have demonstrated that short sleep duration is associated with an increased risk of cardio-metabolic health outcomes including cardiovascular disease mortality, coronary heart disease, type 2 diabetes mellitus, hypertension, and metabolic syndrome. Experimental sleep restriction studies have sought to explain these findings. T...

Objective Insomnia is the most prevalent sleep disorder, with few effective pharmacotherapies. Anecdotal reports and recent preclinical research suggest that cannabinol (CBN), a constituent of Cannabis sativa derived from delta-9-tetrahydrocannabinol, could be an effective treatment. Despite this, the isolated effects of CBN on sleep have yet to be...

Shift workers are at increased risk of obesity and metabolic diseases, but their eating patterns on work and non-workdays are understudied. We aimed to examine whether energy intake and macronutrient intake of day and night shift nurses were different during work and non-workdays. We used a mixed-methods approach to study food intake of shift worki...

Continuous positive airway pressure (CPAP) is the first-line treatment for obstructive sleep apnea (OSA). Although CPAP improves symptoms (e.g., daytime sleepiness), there is a lack of high-quality evidence that CPAP prevents many long-term outcomes, including cognitive impairment, myocardial infarction, and stroke. Observational studies suggest th...

This year the rankings really didn't change at the top of the list. What was notable was the sugar hit from Covid which substantially increased IFs across many health related journals dissipated somewhat. So whilst individual journals might feel disappointed with a drop in impact factor that has in fact happened across the sector largely

Background Individuals living with Alzheimer’s disease (AD) demonstrate extensive deficits in social cognition. To date, no studies have investigated the feasibility of an intranasal oxytocin (INOT) treatment to improve social cognition in individuals living with AD. Objective We conducted a pilot trial to determine recruitment feasibility, enrolm...

Introduction There is a clear need for novel interventions for insomnia disorder. Growing evidence suggests a role of the endogenous cannabinoid system in regulating circadian sleep-wake cycles, highlighting a potential avenue for novel therapeutics. Cannabinol (CBN), a trace cannabinoid formed through oxidation of delta-9-tetrahydrocannbinol (THC)...

Introduction Medicinal cannabis is often cited as a popular alternative to common sleep aids; however, there are limited studies using complex sleep EEG methods examining its’ effects in insomnia disorder. Methods Twenty participants (16 female; mean [SD] age, 47.1 [8.7] years) with insomnia disorder (mean ISI=20.8) completed two 24-hour in-labora...

Reduced heart rate variability can be an early sign of autonomic dysfunction in neurodegenerative diseases and may be related to brain dysfunction in the central autonomic network. As yet, such autonomic dysfunction has not been examined during sleep—which is an ideal physiological state to study brain–heart interaction as both the central and peri...

Introduction: We conducted a systematic review and meta-analysis to review the relationship between midlife dyslipidaemia and lifetime incident dementia. Methods: The databases Medline, Embase, Scopus, Web of Science and Cochrane were searched from inception to 20 February 2022. Longitudinal studies examining the relationship between midlife lipid...

Introduction: We conducted a systematic review and meta-analysis to review the relationship between midlife dyslipidaemia and lifetime incident dementia. Methods: The databases Medline, Embase, Scopus, Web of Science and Cochrane were searched from inception to 20 February 2022. Longitudinal studies examining the relationship between midlife lipid...

Colin Tuft,1 Elie Matar,2 Zoe Menczel Schrire,2 Ronald R Grunstein,2,3 Brendon J Yee,1– 3 Camilla M Hoyos2,4 1Department of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, Sydney, NSW, Australia; 2Centre for Sleep and Chronobiology, Woolcock Institute of Medical Research, Sydney Medical School, Sydney, NSW, Australia; 3Central Clinica...

Individuals living with Alzheimer’s disease (AD) demonstrate global deficits in social cognition. These deficits have been associated with impaired interpersonal relationships amongst caregivers, in turn contributing to a greater sense of caregiver ‘burden’. In other areas of neuropsychiatric disease (i.e., autism spectrum disorder), intranasal oxy...

A growing number of clinical trials (CTs) are investigating the therapeutic potential of cannabidiol (CBD), a non‐intoxicating phytocannabinoid found in Cannabis sativa. These CTs often use crossover experimental designs requiring ‘washout’ (clearance) periods. However, the length of time CBD persists in plasma (its ‘window of detection’) is unclea...

Circadian rhythms alter with ageing and may be aetiologically linked to neurodegeneration. This study explored the association between clinical markers and 1) dim light melatonin onset (DLMO) time and 2) phase angle derived from sleep midpoint, in older adults with varying dementia risks. Participants completed 14 days of actigraphy followed by in-...

Introduction Melatonin has been hypothesised to slow cognitive decline in older adults due to its proposed multiple therapeutic benefits. Methods Participants with Mild Cognitive Impairment (MCI) were recruited from the community for a pilot 12-week randomised placebo-controlled trial of 25mg oral melatonin to target brain oxidative stress and cog...

Introduction There is a clear need for novel interventions for insomnia disorder. Growing evidence suggests a role of the endogenous cannabinoid system in regulating circadian sleep-wake cycles, highlighting a potential avenue for novel therapeutics. Cannabinol (CBN), a trace cannabinoid formed through oxidation of delta-9-tetrahydrocannbinol (THC)...

Introduction Medicinal cannabis is often cited as a popular alternative to common sleep aids; however, there are limited studies using complex sleep EEG methods examining its’ effects in insomnia disorder. Methods Twenty patients (16 female; median [IQR] age, 47 [13.8] years) with insomnia disorder (mean ISI=20.8) completed two 24-hour in-laborato...

Background Obstructive sleep apnoea (OSA) is estimated to occur in up to 70% of older adults. There is accumulating evidence linking OSA with increased risk of cognitive decline and dementia. Here, we present the protocol for a pilot multi-site randomised controlled, parallel open-label trial which will evaluate the feasibility for a full-scale tri...

Background: Among international cardiologists it is unclear whether equipoise exists regarding the benefit of diagnosing and managing obstructive sleep apnea (OSA) to improve atrial fibrillation (AF) outcomes and whether clinical practice and equipoise are linked. Methods: Between January 2019 and June 2020 we distributed a web-based 12-question su...

Light therapy is used to treat sleep and circadian rhythm disorders, yet there are limited studies on whether light therapy impacts electroencephalographic (EEG) activity during sleep. Therefore, we aimed to provide an overview of research studies that examined the effects of light therapy on sleep macro- and micro-architecture in populations with...

There is emerging evidence that obstructive sleep apnea (OSA) is a risk factor for preclinical Alzheimer's disease (AD). An American Thoracic Society workshop was convened that included clinicians, basic scientists, and epidemiologists with expertise in OSA, cognition, and dementia, with the overall objectives of summarizing the state of knowledge...

Background Among international cardiologists it is unclear whether equipoise exists regarding the benefit of diagnosing and managing obstructive sleep apnea (OSA) to improve atrial fibrillation (AF) outcomes and whether clinical practice and equipoise are linked. Methods Between January 2019 and June 2020 we distributed a web-based 12-question sur...

Another year where IFs significantly increased across the whole of science. In sleep research a number of newer journals (notably Sleep Health and Nature and Science of Sleep) had very large climbs up the ranking list in 2020. However this year there has been a return to the more traditional ranking order.

Purpose Consistent predictors of weight loss outcomes with very low-energy diets (VLEDs) in obstructive sleep apnea (OSA) have not been identified. This study aimed to identify variables predictive of weight loss success in obese patients with OSA undertaking an intensive weight loss programme. Methods We analysed biological, psychological, and be...

Epidemiologic studies have demonstrated that short sleep duration is associated with an increased risk of cardio-metabolic health outcomes including cardiovascular disease mortality, coronary heart disease, type 2 diabetes mellitus, hypertension, and metabolic syndrome. Experimental sleep restriction studies have sought to explain these findings. T...

Background Cannabidiol (CBD), a major cannabinoid of Cannabis sativa, is widely consumed in prescription and non-prescription products. While CBD is generally considered ‘non-intoxicating’, its effects on safety-sensitive tasks are still under scrutiny. Aim We investigated the effects of CBD on driving performance. Methods Healthy adults ( n = 17...

Sleep disturbances are often cited as a primary reason for medicinal cannabis use and there is increasing clinical interest in the therapeutic potential of cannabinoids in treating sleep disorders. Burgeoning evidence suggests a role of the endocannabinoid system in regulating the circadian sleep-wake cycle, highlighting a potential avenue for deve...

Study Objectives Untreated obstructive sleep apnea (OSA) is associated with cognitive deficits and altered brain electrophysiology. We evaluated the effect of continuous positive airway pressure (CPAP) treatment on quantitative sleep electroencephalogram (EEG) measures and cognitive function. Methods We studied 162 OSA patients (age 50±13, AHI 35....

Importance Melatonin is commonly used for sleep and jetlag at low doses. However, there is less documentation on the safety of higher doses which are being increasingly used for a wide variety of conditions, including more recently COVID-19 prevention and treatment. Objective To investigate the safety of higher doses of melatonin in adults. Data...

Aims Diabetes is an established risk factor for dementia. This study aimed to examine the relationship between various cognitive domains, brain oxidative stress and markers of diabetes in older adults at risk for dementia. Methods Older adults at risk for dementia underwent comprehensive neuropsychological and medical assessment. At risk was defin...

Purpose This study aimed to determine the effects of a standard dose of zopiclone (7.5mg) on sleep spindle activity and to assess if potential changes in sleep spindles correlate with improvements in next-day measures of sleepiness and simulated driving performance in people with obstructive sleep apnoea (OSA). Methods Thirty-one people with OSA c...

Introduction Light interventions have been used to treat sleep and circadian rhythm disorders. However, there are limited studies on the effect of light on electroencephalographic (EEG) activity during sleep. Therefore, we aimed to provide an overview of research using light intervention on sleep macro- and micro-architecture. Methods We searched...

The oxytocin (OXT) system has garnered considerable interest due to its influence on diverse behaviours. However, scant research has considered the influence of oxytocin on sleep-wake and sleep-related behaviour and neurobiology. Consequently, the objective of this systematic review was to assess the extant preclinical and clinical evidence for the...

Background and objective Use of in-laboratory polysomnography (PSG) to diagnose obstructive sleep apnoea (OSA) is cost and resource intensive. Questionnaires, physical measurements and home monitors have been studied as potential simpler alternatives. This study aimed to develop a diagnostic model for OSA for use in primary care. Methods Primary c...

Many jurisdictions use point‐of‐collection (POC) oral fluid testing devices to identify driving under the influence of cannabis, indexed by the presence of Δ9‐tetrahydrocannabinol (THC), an intoxicating cannabinoid, in oral fluid. While use of the non‐intoxicating cannabinoid, cannabidiol (CBD), is not prohibited among drivers, it is unclear whethe...

Quick tabular and graphical update to incorporate 2020 and 2019 impact factor data on sleep research journals

Background: During exercise, dynamic hyperinflation (DH), measured by a reduction in inspiratory capacity (IC), increases exertional dyspnoea and reduces functional capacity in many patients with severe COPD. While non-invasive ventilation (NIV) during exercise can improve exercise duration, the effect on DH is unclear. Research questions: In pe...

Study Objectives: Cardiovascular autonomic dysfunction, as measured by short-term diurnal heart rate variability (HRV), has been reported in older adults with mild cognitive impairment (MCI). However, it is unclear whether this impairment also exists during sleep in this group. We therefore compared overnight HRV during sleep in older adults with M...

Rationale: Evidence suggests that continuous positive airway pressure (CPAP) treatment promotes weight gain in obstructive sleep apnea (OSA) patients. It is unclear whether weight gain is influenced by CPAP adherence or comorbid disorders. Objectives: To examine the CPAP effects on body mass index (BMI) and local adiposity，and the potential mode...

Introduction Melatonin has multiple proposed therapeutic benefits including antioxidant properties, synchronisation of the circadian system and lowering of blood pressure. In this protocol, we outline a randomised controlled trial to assess the feasibility, acceptability and tolerability of higher dose (25 mg) melatonin to target brain oxidative st...

Objective: This study aimed to investigate the relationship between obesity and oxidative stress in older adults at risk for dementia. It also aimed to explore the influence of physical activity on the relationship between obesity and oxidative stress in this at risk cohort. Methods: Older adults at risk for dementia underwent comprehensive medi...

Insomnia disorder with objective short sleep duration (less than 6 hours of objective sleep or sleep efficiency less than 85%) has been considered as a biologically severe subtype of insomnia associated with a higher risk of cardiometabolic disease morbidity. This systematic review and meta-analysis firstly compared insomnia disorder with objective...

Background Nocturnal high‐frequency heart rate variability (HF‐HRV), an indicator of parasympathetic tone, is decreased in older adults with amnestic mild cognitive impairment (aMCI) during slow wave sleep. However, it is unclear whether or how this parasympathetic dysfunction relates to early cognitive decline. We therefore aimed to explore associ...

Background Circadian rhythms are altered with ageing, mild cognitive impairment and dementia and may be aetiologically linked to neurodegeneration. The gold standard measure of the circadian system is melatonin. This can be measured using Dim‐Light Melatonin Onset (DLMO), which measures the initial rise of melatonin signalling preceding sleep. Howe...

Study Objectives Cardiovascular autonomic dysfunction, as measured by short-term diurnal heart rate variability (HRV), has been reported in older adults with mild cognitive impairment (MCI). However, it is unclear whether this impairment also exists during sleep in this group. We, therefore, compared overnight HRV during sleep in older adults with...

Study Objectives Obesity is a common and reversible risk factor for obstructive sleep apnea (OSA). However, there is substantial unexplained variability in the amount of OSA improvement for any given amount of weight loss. Facial photography is a simple, inexpensive, and radiation-free method for craniofacial assessment. Our aims were (1) to determ...

Objective Interest in the use of cannabidiol (CBD) is increasing worldwide as its therapeutic effects are established and legal restrictions moderated. Unlike Δ⁹‐tetrahydrocannabinol (Δ⁹‐THC), CBD does not appear to cause cognitive or psychomotor impairment. However, further assessment of its effects on cognitively demanding day‐to‐day activities,...

Background Depression is common in patients with obstructive sleep apnea (OSA). Whether treating OSA with continuous positive airway pressure (CPAP) improves depressive symptoms remains inconclusive. We examined the impact of CPAP on depressive symptoms in OSA patients compared to sham CPAP. Methods A sub-analysis of two previous randomized sham-c...

Cannabinoids, including the two main phytocannabinoids Δ⁹-tetrahydrocannabinol (THC) and cannabidiol (CBD), are being increasingly utilised as pharmacological interventions for sleep disorders. THC and CBD are known to interact with the endocannabinoid and other neurochemical systems to influence anxiety, mood, autonomic function, and circadian sle...

Introduction Insomnia is a highly prevalent and costly condition that is associated with increased health risks and healthcare utilisation. Anecdotally, cannabis use is frequently reported by consumers to promote sleep. However, there is limited research on the effects of cannabis on sleep and daytime function in people with insomnia disorder using...

Background: Depression is common in older people and is associated with underlying brain change increasing the risk of dementia. Sleep disturbance is frequently reported by those with lifetime depression, however whether circadian misalignment also exists is unclear. We aimed to examine circadian rhythms and sleep associations in older patients wi...

Older adults with mild cognitive impairment (MCI) are at-risk of developing dementia, particularly Alzheimer’s disease. While some research suggests that alterations in sleep architecture may mediate cognitive decline, the nature and magnitude of changes to sleep macro- (sleep stages) and micro-architecture (electroencephalography (EEG) oscillation...

Impact factors and ranking lists of research journals are very often used to judge our career achievements and progression by employers and granting bodies. However, a comprehensive list for the interdisciplinary field of sleep research does not currently exist because our journals tend to be placed into discipline‐specific lists that do not cope w...

Background Obstructive sleep apnea is associated with an increased risk of developing mild cognitive impairment and dementia. Intermittent nocturnal hypoxemia in obstructive sleep apnea is associated with brain changes in key regions that underpin memory. Objective To determine whether older adults with severe nocturnal hypoxemia would exhibit red...

Cardiovascular autonomic dysfunction, as measured by short‐term diurnal Heart Rate Variability (HRV), has been reported in older adults with Mild Cognitive Impairment (MCI). It is unclear whether this impairment exists nocturnally. Sleep disturbance in older people with MCI may be associated with nocturnal autonomic imbalance. We investigated if no...

Introduction: Epidemiological studies show that shift workers are at increased risk of cardiovascular diseases, metabolic dysfunction, diabetes, and obesity. Previous research has shown no difference in energy intake between night and day shifts only; however, it remains unclear whether other non-night shift patterns are different to night shift. O...

Magnesium supplementation is often suggested for restless legs syndrome (RLS) or period limb movement disorder (PLMD) based on anecdotal evidence that it relieves symptoms and because it is also commonly recommended for leg cramps. We aimed to review all articles reporting the effects of magnesium supplementation on changes in RLS and/or PLMD. We c...

Background: Obstructive sleep apnoea (OSA) is associated with an increased risk of developing dementia and mild cognitive impairment. A core symptom of OSA, oxygen desaturation, is associated with brain changes in key regions that underpin memory. In this study, we hypothesised that those with severe oxygen desaturation would exhibit reduced functi...

Effective treatment of obstructive sleep apnoea (OSA) is primarily determined by adherence to the selected intervention. The most common treatment pathways are mechanical devices such as continuous positive airway pressure (CPAP) or a mandibular advancement device, often combined with weight loss therapy. Weight reduction is usually an adjunct ther...

Study objectives Recent evidence suggests that compared to peripheral blood pressure (BP), central BP may be more strongly associated with target organ damage and cardiovascular morbidity and mortality. Technological advances now allow the ambulatory measurement of peripheral and central BP over 24 h. For the first time, we set out to characterise...

Cardiovascular disease in older people is often linked with cognitive impairment, particularly in domains of executive function and processing speed. Our aims examined whether carotid-femoral pulse wave velocity (PWV) related to subtle changes of executive function and processing speed. Fifty-six individuals with subjective mood and/or cognitive co...