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ABSTRACT: Background/Aims: This study used proton magnetic resonance spectroscopy ((1)H MRS) to evaluate the neurochemistry of the anterior cingulate cortex (ACC) in adolescents with generalized anxiety disorder (GAD). Methods: Adolescents with GAD (n = 10) and healthy subjects (n = 10) underwent a (1)H MRS scan at 4 T. Glutamate (Glu), N-acetyl aspartate, creatine (Cr) and myo-inositol concentrations were measured in the ACC and were compared between untreated adolescents with GAD and age- and sex-matched healthy subjects. Results: Glu/Cr ratios in the ACC correlated with the severity of both generalized anxiety symptoms on the Pediatric Anxiety Rating Scale and with total anxiety symptom severity as measured by the Hamilton Anxiety Rating Scale, but did not differ between adolescents with GAD and healthy subjects. In addition, no differences in N-acetyl aspartate, Cr, or myo-inositol were detected between groups. Conclusion: These findings suggest that Glu/Cr in untreated adolescents with GAD may relate to the severity of anxiety symptoms and raise the possibility that dysregulation of Glu within the ACC may be linked to the pathophysiology of pediatric GAD.
Neuropsychobiology 04/2013; 67(4):224-229. · 2.67 Impact Factor
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ABSTRACT: BACKGROUND: Despite recent data implicating functional abnormalities in the neurocircuitry underlying emotional processing in pediatric anxiety disorders, little is known regarding neurostructural abnormalities within these systems. METHODS: Using voxel-based morphometry, gray and white matter volumes were compared in 15 medication-free adolescents with generalized anxiety disorder (GAD; and no comorbid major depressive disorder) and 28 age- and sex-matched healthy comparison subjects. RESULTS: Compared to healthy adolescents, youth with GAD had larger gray matter volumes in the right precuneus and right precentral gyrus and decreased gray matter volumes in the left orbital gyrus and posterior cingulate. White matter volumes were decreased in the left medial and superior frontal gyrus and were increased in the left inferior temporal gyrus in youth with GAD relative to healthy subjects. CONCLUSIONS: Adolescents with GAD, who are early in the course of their illness, exhibit abnormalities in neural structures that subserve threat appraisal, modulation of fear responses, attachment, and mentalization.
Depression and Anxiety 03/2013; · 4.18 Impact Factor
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ABSTRACT: Discrete jumps in knowledge, as exemplified by single-trial learning, are critical to survival. Despite its importance, however, one-trial learning remains understudied. We sought to better understand the brain activity adaptations that track punctuated changes in associative knowledge by studying visual-motor associative learning with functional magnetic resonance imaging. Human and primate neurophysiological studies of feedback-based learning indicate that performance feedback elicits high activity at first that diminishes rapidly with repeated success. Based on these findings we hypothesized a network of brain regions would track the importance of feedback, which is large early in learning and diminishes thereafter. Specifically, based on neurophysiological findings, we predicted that frontal and striatal regions would show a large activation to first trial feedback and a subsequent reduction selective to performance feedback but not stimulus cue presentation. We observed that the striatum and frontal cortex as well as several other cortical and subcortical sites exhibited this pattern. These findings match our prediction for activity in frontal and striatal regions. Furthermore, these observations support the more general hypothesis that a large network of regions participates in the associative process once the behavioral goal is definitively identified by first trial performance feedback. Activity in this network declines upon further rehearsal but only for feedback presentation. We suggest that, based on the timing of this process, these regions participate in binding together stimulus cue, motor response, and performance feedback information into an association that is used to accurately perform the task on after the first trial.
Brain research 04/2012; 1458:56-66. · 2.46 Impact Factor
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ABSTRACT: Bipolar I disorder is characterized by affective symptoms varying between depression and mania. The specific neurophysiology responsible for depression in bipolar I disorder is unknown but previous neuroimaging studies suggest impairments in corticolimbic regions that are responsible for regulating emotion. The amygdala seems to play a central role in this network and is responsible for appraisal of emotional stimuli. To further understand the role of the amygdala in the generation of mood symptoms, we used functional magnetic resonance imaging (fMRI) to examine a group of patients with bipolar I disorder longitudinally.
fMRI was used to study regional brain activation in 15 bipolar I disorder patients followed for up to one year. Patients received an fMRI scan during an initial manic episode and a subsequent depressive episode. During the scans, patients performed an attentional task that incorporated emotional pictures. Fifteen healthy comparison subjects were also scanned at baseline and then at four months. Whole-brain functional connectivity analysis was performed using the left and right amygdala as seed regions.
Significant changes in amygdala functional connectivity were found between the manic and depressed phases of illness. The right amygdala was significantly more positively correlated with the left inferior frontal gyrus during mania and with the right insula during depression. There were no significant differences in left amygdala correlations across mood states in the bipolar I disorder group.
In the transition from a manic/mixed episode to a depressive episode, subjects with bipolar I disorder showed unique changes in cortical-amygdala functional connectivity. Increased connectivity between the insula and right amygdala may generate excessive positive feedback, in that both of these regions are involved in the appraisal of emotional stimuli. Increased correlation between the right amygdala and the inferior frontal gyrus in mania is consistent with previous findings of decreased prefrontal modulation of limbic regions in mania. These differences in connectivity may represent neurofunctional markers of mood state as they occurred in the same individuals across manic and depressive episodes.
Bipolar Disorders 03/2012; 14(2):175-84. · 5.29 Impact Factor
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ABSTRACT: Changes in diffusion tensor imaging (DTI) values co-occur with neurological and functional changes after stroke. However, quantitative DTI metrics have not been examined in response to participation in targeted rehabilitative interventions in chronic stroke. The primary purpose of this pilot study was to examine whether changes in DTI metrics co-occur with paretic arm movement changes among chronic stroke patients participating in a regimen of electrical stimulation targeting the paretic arm. Three subjects exhibiting stable arm hemiparesis were administered 30-minute (n = 1) or 120-minute (n = 2) therapy sessions emphasizing paretic arm use during valued, functional tasks and incorporating an electrical stimulation device. These sessions occurred every weekday for 8 weeks. A fourth subject served as a treatment control, participating in a 30-minute home exercise regimen without electrical stimulation every weekday for 8 weeks. DTI and behavioral outcome measures were acquired at baseline and after intervention. DTI data were analyzed using a region of interest (ROI) approach, with ROIs chosen based on tract involvement in sensorimotor function or as control regions. Behavioral outcome measures were the Fugl-Meyer Scale (FM) and the Action Research Arm Test (ARAT). The treatment control subject exhibited gains in pinch and grasp, as shown by a 5-point increase on the ARAT. The subject who participated in 30-minute therapy sessions exhibited no behavioral gains. Subjects participating in 120-minute therapy sessions displayed consistent impairment reductions and distal movement changes. DTI changes were largest in subjects two and three, with mean diffusivity (MD) decreases in the middle cerebellar peduncle and posterior limb of the internal capsule following treatment. No changes in fractional anisotropy (FA) were observed for sensorimotor tracts. Our preliminary results suggest that active rehabilitative therapies augmented by electrical stimulation may induce positive behavioral changes which are underscored by DTI changes indicative of increased white matter tract integrity in regions specific to sensory-motor function.
Brain Imaging and Behavior 12/2011; · 1.66 Impact Factor
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ABSTRACT: Although nonallergic rhinitis (NAR) patients tend to be more sensitive to chemical/olfactory stimuli, a suprathreshold olfactory response or the presence of specific olfactory receptor genes do not explain why their symptoms are triggered by such exposures.
To investigate differential neurogenic responses to azelastine in NAR patients, using functional magnetic resonance imaging (fMRI) in response to specific olfactory triggers.
A longitudinal study design on 12 subjects with a physician diagnosis of NAR previously demonstrated to be clinically responsive to intranasal azelastine (Astelin) was performed. Subjects underwent fMRI during exposure to unpleasant (hickory smoke) and pleasant (vanilla) odorants while off and then on azelastine for 2 weeks. The olfactory fMRI paradigm consisted of a visually triggered sniff every 21 seconds with synchronized delivery of a 4 second pulse of odorant. Each odorant was presented 18 times over 4-6-minute fMRI runs. Continuous fresh air was presented to wash out each odorant after presentation.
Nonallergic rhinitis patients exhibited increased blood flow to several regions of the brain in response to both pleasant and unpleasant odorants, specifically in odor-sensitive regions, while off intranasal azelastine. Treatment with intranasal azelastine significantly attenuated blood flow to regions of the brain relevant to either olfactory sensation or sensory processing in response to these odorants compared with fresh air.
The general reduction compared with increase in brain activation in NAR patients on versus off azelastine suggests that a possible effect of this medication may be reduction of brain responses to odorants.
Annals of allergy, asthma & immunology: official publication of the American College of Allergy, Asthma, & Immunology 06/2011; 106(6):527-32. · 2.83 Impact Factor
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ABSTRACT: Of all mood states, patients in mixed episodes of bipolar disorder are at the greatest risk for impulsive behaviors including attempted suicide. The aim of this study was to examine whether the neural correlates of motor impulsivity are distinct in patients with mixed mania.
Ten patients with bipolar disorder in a mixed episode (BP-M), 10 bipolar comparison participants in a depressed episode (BP-D), and 10 healthy comparison (HC) participants underwent functional MRI while performing a Go/No-Go task of motor impulsivity.
Both patient groups had elevated, self-rated motor impulsiveness scores. The BP-M group also had a trend-level increase in commission errors relative to the HC group on the Go/No-Go task. While the full sample strongly activated a ventrolateral prefrontal-subcortical brain network, the BP-M group activated the amygdala and frontal cortex more strongly than the HC group, and the thalamus, cerebellum, and frontal cortex more strongly than the BP-D group.
This study is primarily limited by a relatively small sample size.
Higher commission error rates on the Go/No-Go task suggest increased vulnerability to impulsive responding during mixed episodes of bipolar disorder. Moreover, the distinct pattern of increased brain activation during mixed mania may indicate a connection between behavioral impulsivity and a failure of neurophysiological "inhibition", especially in the amygdala.
Journal of affective disorders 05/2011; 133(1-2):333-9. · 3.76 Impact Factor
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Stephen M Strakowski, James C Eliassen,
Martine Lamy,
Michael A Cerullo,
Jane B Allendorfer,
Michelle Madore,
Jing-Huei Lee,
Jeffrey A Welge,
Melissa P DelBello,
David E Fleck,
Caleb M Adler
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ABSTRACT: Bipolar I disorder is defined by the occurrence of mania. The presence of mania, coupled with a course of illness characterized by waxing and waning of affective symptoms, suggests that bipolar disorder arises from dysfunction of neural systems that maintain emotional arousal and homeostasis. We used functional magnetic resonance imaging (fMRI) to study manic bipolar subjects as they performed a cognitive task designed to examine the ventrolateral prefrontal emotional arousal network.
We used fMRI to study regional brain activation in 40 DSM-IV manic bipolar I patients and 36 healthy subjects while they performed a continuous performance task with emotional and neutral distracters. Event-related region-of-interest analyses were performed to test the primary hypothesis. Voxelwise analyses were also completed.
Compared with healthy subjects, the manic subjects exhibited blunted activation to emotional and neutral images, but not targets, across most of the predefined regions of interest. Several additional brain regions identified in the voxelwise analysis also exhibited similar differences between groups, including right parahippocampus, right lingual gyrus, and medial thalamus. In addition to these primary findings, the manic subjects also exhibited increased activation in response to targets in a number of brain regions that were primarily associated with managing affective stimuli. Group differences did not appear to be secondary to medication exposure or other confounds.
Bipolar manic subjects exhibit blunted brain fMRI response to emotional cues throughout the ventrolateral prefrontal emotional arousal network. Disruption of this emotional network may contribute to the mood dysregulation of bipolar disorder.
Biological psychiatry 11/2010; 69(4):381-8. · 8.93 Impact Factor
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ABSTRACT: Insulin resistance is implicated in the pathophysiological changes associated with Alzheimer's disease, and pharmaceutical treatments that overcome insulin resistance improve memory function in subjects with mild cognitive impairment (MCI) and early Alzheimer's disease. Chromium (Cr) supplementation improves glucose disposal in patients with insulin resistance and diabetes. We sought to assess whether supplementation with Cr might improve memory and neural function in older adults with cognitive decline. In a placebo-controlled, double-blind trial, we randomly assigned 26 older adults to receive either chromium picolinate (CrPic) or placebo for 12 weeks. Memory and depression were assessed prior to treatment initiation and during the final week of treatment. We also performed functional magnetic resonance imaging (fMRI) scans on a subset of subjects. Although learning rate and retention were not enhanced by CrPic supplementation, we observed reduced semantic interference on learning, recall, and recognition memory tasks. In addition, fMRI indicated comparatively increased activation for the CrPic subjects in right thalamic, right temporal, right posterior parietal, and bifrontal regions. These findings suggest that supplementation with CrPic can enhance cognitive inhibitory control and cerebral function in older adults at risk for neurodegeneration.
Nutritional Neuroscience 06/2010; 13(3):116-22. · 1.56 Impact Factor
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Robert K McNamara,
Jessica Able,
Ronald Jandacek,
Therese Rider,
Patrick Tso, James C Eliassen,
David Alfieri,
Wade Weber,
Kelly Jarvis,
Melissa P DelBello,
Stephen M Strakowski,
Caleb M Adler
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ABSTRACT: Emerging evidence suggests that docosahexaenoic acid (DHA, 22:6n-3), the principal omega-3 (n-3) fatty acid in brain gray matter, positively regulates cortical metabolic function and cognitive development. However, the effects of DHA supplementation on functional cortical activity in human subjects are unknown.
The objective was to determine the effects of DHA supplementation on functional cortical activity during sustained attention in human subjects.
Healthy boys aged 8-10 y (n = 33) were randomly assigned to receive placebo or 1 of 2 doses of DHA (400 or 1200 mg/d) for 8 wk. Relative changes in cortical activation patterns during sustained attention at baseline and endpoint were determined by functional magnetic resonance imaging.
At 8 wk, erythrocyte membrane DHA composition increased significantly from baseline in subjects who received low-dose (by 47%) or high-dose (by 70%) DHA but not in those who received placebo (-11%). During sustained attention, both DHA dose groups had significantly greater changes from baseline in activation of the dorsolateral prefrontal cortex than did the placebo group, and the low-dose and high-dose DHA groups had greater decreases in the occipital cortex and cerebellar cortex, respectively. Relative to low-dose DHA, high-dose DHA resulted in greater decreases in activation of bilateral cerebellum. The erythrocyte DHA composition was positively correlated with dorsolateral prefrontal cortex activation and was inversely correlated with reaction time, at baseline and endpoint.
Dietary DHA intake and associated elevations in erythrocyte DHA composition are associated with alterations in functional activity in cortical attention networks during sustained attention in healthy boys. This trial was registered at clinicaltrials.gov as NCT00662142.
American Journal of Clinical Nutrition 04/2010; 91(4):1060-7. · 6.67 Impact Factor
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ABSTRACT: Conventional electrical stimulation modalities are limited by their lack of opportunities for motor learning and, consequently, their impact on function. Other rehabilitative regimens necessitate affected hand and wrist movement for patients to be included, making them implausible for most patients. In light of these challenges, the current study examined the efficacy of a repetitive task-specific training (RTP) regimen using an electrical stimulation neuroprosthesis in stroke patients exhibiting no affected wrist or hand movement.
Eight chronic stroke patients (mean = 46.5 months) with moderately affected arm motor deficits participated in 30-minute therapy sessions occurring every weekday for 8 weeks. During the sessions, they wore the neuroprosthesis to enable performance of valued activities identified largely by the patients. To ensure transfer to their real-world environments, most sessions were home based, with the patients coming to the clinic for "tune-up" sessions (eg, adjusting the stimulation parameters, exercises, and/or fit of the device) twice every other week (a total of 8 clinical visits). Outcomes were evaluated using the Action Research Arm Test (ARAT) and the upper extremity section of the Fugl-Meyer Assessment (FM), the amount of use scale of the Motor Activity Log (MAL), and high-field functional magnetic resonance imaging (fMRI).
Before the intervention, patients exhibited stable motor deficits. After the intervention, they exhibited ARAT and FM score increases (+2.85 and +2.2, respectively). Postintervention fMRI revealed significant increases in cortical activation, possibly brought about by markedly increased affected arm use patterns on the MAL (+0.97).
An affected arm RTP program incorporating NEURSTIM appears to increase affected arm use and elicit neural changes in more impaired patients. These factors may conspire to produce motor changes, although motor changes are smaller in this population than with less impaired patients. The program may act as a "bridge" to other promising regimens.
Neurorehabilitation and neural repair 02/2010; 24(2):195-203. · 4.49 Impact Factor
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ABSTRACT: To identify differential patterns of brain activation between adolescents with bipolar disorder and adolescents with attention-deficit hyperactivity disorder (ADHD) to better understand the neurophysiology of both disorders. We hypothesized that subjects with ADHD would show altered activation in brain regions involved in executive and sustained attention. In contrast, we hypothesized that bipolar subjects would show altered brain activation in regions responsible for emotionally homeostasis, including the striatum and amygdala.
Functional magnetic resonance imaging was performed during a continuous performance task with a response inhibition component in 11 adolescents with bipolar disorder during a manic episode, 10 adolescents with ADHD, and 13 healthy adolescents.
There were no differences in behavioural performance among the three groups. Compared with bipolar subjects, subjects with ADHD showed increased activation in the superior temporal lobe during successful response inhibition. Although bipolar subjects did not show activation differences in the striatum or amygdala compared with ADHD subjects, increased left parahippocampal activation in the bipolar group was associated with increased manic symptoms.
The patterns of brain activation observed in the current study support divergent patterns of neurophysiological dysfunction in individuals with bipolar disorder as compared with those with ADHD. Therefore, the impulsive behaviour seen in both disorders may be the consequence of dysfunction in different brain regions, and further research may help identify neurobiological markers that are specific to each condition.
Early Intervention in Psychiatry 08/2009; 3(3):189-97. · 0.92 Impact Factor
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ABSTRACT: and purpose. Mental practice (MP), which involves cognitive rehearsal of physical movements, is a noninvasive, inexpensive method of enabling repetitive, task-specific practice (RTP). Recent, randomized controlled data suggest that MP, when combined with an RTP therapy program, increases affected arm use and function significantly more than RTP only. As a next step, this 10-subject case series examined the possibility that cortical plasticity is a mechanism underlying the treatment effect of MP when combined with RTP.
Ten chronic stroke patients (mean = 36.7 months) exhibiting stable, moderate motor deficits received 30-minute therapy sessions for their affected arms, occurring 3 days/week for 10 weeks, and emphasizing valued activities of daily living (ADLs). Directly after therapy, subjects received 30-minute MP sessions, which required MP of the ADLs performed during therapy. Behavioral outcomes were blindly evaluated using the Action Research Arm Test (ARAT) and the Fugl-Meyer Assessment (FM). Functional magnetic resonance imaging (fMRI) was administered before and after intervention to assess cortical changes.
Before intervention, subjects exhibited stable motor deficits. After intervention, subjects exhibited ARAT and FM score increases (+5.3 and +4.2, respectively) and clinically significant gains in ADLs. Postintervention fMRI revealed significant increases in activation to wrist flexion and extension of the affected hand in the premotor area and primary motor cortex ipsilateral and contralateral to the affected hand, as well as in superior parietal cortex ipsilateral to the affected hand. Decreased activation was noted in parietal cortex of the hemisphere ipsilateral to the affected hand. These changes correlated with anatomical regions in which behavioral changes were observed in the ARAT and FM.
MP is an easy to use, cost-effective strategy that was again shown to improve affected arm outcomes after stroke. This is the first study to demonstrate alteration in the cortical map in response to MP training.
Neurorehabilitation and neural repair 02/2009; 23(4):382-8. · 4.49 Impact Factor
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ABSTRACT: Impulsivity is common in bipolar disorder, especially during mania. Understanding the functional neuroanatomy of response inhibition, one component of impulsivity, might clarify the neural substrate of bipolar disorder.
Sixteen DSM-IV first-episode, manic bipolar patients and 16 matched healthy subjects were examined during a first manic episode using functional magnetic resonance imaging while performing a response inhibition task. All subjects were studied using a 4.0 Tesla Varian Unity INOVA Whole Body MRI/MRS system. The response inhibition task was presented using non-ferromagnetic goggles, and task performance was recorded during scan acquisition. Imaging data were analysed using analysis of functional neuroimages. Group contrasts were made for the specific response inhibition measure.
The groups performed the task similarly, although both demonstrated relatively poor rates of target response, but high rates of successful 'stops'. Despite similar behavioural results, the groups showed significantly different patterns of functional magnetic resonance imaging brain activation. Specifically, during response inhibition, the healthy subjects exhibited significantly greater activation in anterior and posterior cingulate, medial dorsal thalamus, middle temporal gyrus, and precuneus. The bipolar patients exhibited prefrontal activation (BA 10) that was not observed in healthy subjects.
Bipolar and healthy subjects exhibit different patterns of brain activation to response inhibition; these differences may reflect different functional neuroanatomic approaches to response inhibition between the two groups.
Early Intervention in Psychiatry 12/2008; 2(4):225-33. · 0.92 Impact Factor
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ABSTRACT: Progressive decline of memory functions has been observed in patients with chronic medication-resistant epilepsy. The progression likely relates to the effects of epileptiform discharges, seizures, and medications on the processes of encoding and retrieval. The goal of the study described here was to use functional MRI (fMRI) to examine the effects of chronic epilepsy on verbal recognition memory. We enrolled 12 patients with medication-resistant epilepsy (5 with right and 7 with left hemispheric seizure onset) and 18 healthy controls matched for age, gender, and handedness. Subjects underwent fMRI at 3T using a word recognition task during which they had to recall if words presented during scanning were words they had learned prior to scanning. Although we noted many similarities in the fMRI activation patterns between the subjects with epilepsy and the healthy subjects in areas typically involved in memory processing, testing of the interaction effects for target-foil differences between groups revealed several differences in activation including the right insula, the left cuneus, and the bilateral subgenual anterior cingulate cortex (ACC). In patients with epilepsy, these regions exhibited greater activation for targets than foils, but in healthy subjects the difference was reversed (right insula), absent (left cuneus), or included deactivation to target words (pregenual ACC). These differences were seen despite similar performance during the memory task, suggesting that activations observed in these additional regions may represent compensatory processes for verbal recognition memory that are induced by chronic brain injury related to recurrent seizures.
Epilepsy & Behavior 08/2008; 13(3):463-9. · 2.34 Impact Factor
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ABSTRACT: Although advances in the clinical criteria of various axis I psychiatric disorders are continually being made, there is still considerable overlap in the clinical features, and diagnosis is often challenging. As a result, there has been substantial interest in using morphometric magnetic resonance imaging to better characterize these diseases and inform diagnosis. Region of interest and voxel-based morphometry studies are reviewed herein to examine the extent to which these goals are being met across various psychiatric disorders. It is concluded based on the studies reviewed that specific patterns of regional loss, although present in certain axis I disorders, are not, as yet, diagnostically useful. However, advances in outcome and treatment monitoring show considerably more promise for rapid application in psychiatry.
Topics in magnetic resonance imaging: TMRI 05/2008; 19(2):131-42.
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Schizophrenia Research 01/2008; 97(1-3):294-6. · 4.75 Impact Factor
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ABSTRACT: Bipolar disorder is characterized by disturbed mood homeostasis accompanied by cognitive impairments that appear to persist during euthymia. Cognitive probes, coupled with neuroimaging, provide an approach toward clarifying the neurophysiology of bipolar disorder.
Sixteen patients with euthymic bipolar disorder and 16 healthy subjects underwent functional magnetic resonance imaging (fMRI) while performing a counting Stroop interference task and a control condition. Task performance was correlated with regional brain activation differences between groups, and the effect on brain activation of receiving versus not receiving medications was evaluated.
Bipolar patients exhibited impaired task performance relative to the healthy subjects. In addition, the two groups demonstrated significantly different patterns of brain activation during the interference task. Healthy subjects exhibited relatively increased activation in temporal cortical regions, middle frontal gyrus, putamen, and midline cerebellum. Bipolar subjects exhibited relatively greater activation in the medial occipital cortex. The groups demonstrated different associations between task performance and fMRI activation in these brain regions. No differences in activation in these regions were observed between patients who were versus those who were not receiving medications; however, patients receiving medications exhibited greater activation in the anterior cingulate and dorsolateral prefrontal cortex.
These differences suggest that patients with euthymic bipolar disorder fail to activate brain regions associated with performance of an interference task, which may contribute to impaired task performance. Medications do not explain these differences but may influence activation of brain regions primarily associated with performing an interference task.
American Journal of Psychiatry 10/2005; 162(9):1697-705. · 12.54 Impact Factor
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ABSTRACT: The role of intensity of aphasia therapy was investigated using functional magnetic resonance imaging (fMRI) to document changes in neural activation patterns associated with massed versus distributed therapy in an individual with chronic conduction aphasia.
Language therapy targeted word-finding deficits and phonological processing. fMRI scans were acquired at baseline, after massed therapy, and after distributed therapy.
Treatment was effective, as demonstrated by increases in performance on standardized measures, narrative analysis, and task performance in the fMRI scanner. Task improvement across fMRI testing sessions corresponded with increases in fMRI blood oxygenation level dependent (BOLD) signal. Greatest behavioral gains and BOLD signal increases occurred after massed therapy, with slight gains accompanying distributed therapy. Increases in fMRI BOLD signal occurred after therapy in left basal ganglia and right hemisphere frontotemporal cortex.
Intensity of aphasia therapy impacts the recovery process and warrants additional research. Basal ganglia and right hemisphere structures may be important neural substrates for aphasia recovery.
Topics in Stroke Rehabilitation 15(5):468-83. · 0.95 Impact Factor
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ABSTRACT: Brain-mapping techniques have proven to be vital in understanding the molecular, cellular, and functional mechanisms of recovery after stroke. This article briefly summarizes the current molecular and functional concepts of stroke recovery and addresses how various neuroimaging techniques can be used to observe these changes. The authors provide an overview of various techniques including diffusion-tensor imaging (DTI), magnetic resonance spectroscopy (MRS), ligand-based positron emission tomography (PET), single-photon emission computed tomography (SPECT), regional cerebral blood flow (rCBF) and regional metabolic rate of glucose (rCMRglc) PET and SPECT, functional magnetic resonance imaging (fMRI), near infrared spectroscopy (NIRS), electroencephalography (EEG), magnetoencephalography (MEG), and transcranial magnetic stimulation (TMS). Discussion in the context of poststroke recovery research informs about the applications and limitations of the techniques in the area of rehabilitation research. The authors also provide suggestions on using these techniques in tandem to more thoroughly address the outstanding questions in the field.
Topics in Stroke Rehabilitation 15(5):427-50. · 0.95 Impact Factor
