Recognition of Human Emotions from Cerebral Blood Flow Changes in the Frontal Region: A Study with Event‐Related Near‐Infrared Spectroscopy

ABSTRACT

BACKGROUNDS AND PURPOSE

The aim of this study is to develop a near‐infrared spectroscopy (NIRS)‐based system that recognizes pleasant and unpleasant human emotions based on cerebral blood flow (CBF) in order to understand the minds of patients whose brain function is severely impaired. The forehead region is easily accessible to NIRS measurements, whereas the role of the anterior prefrontal cortex (PFC) in the processing of emotion remains to be elucidated.

METHODS

Initially, using event‐related NIRS we examined changes in oxygenated hemoglobin (oxy‐Hb) as an indicator of regional CBF changes, which reflect brain activity directly related to emotions, but not to cognitive operations in the anterior frontal regions, during viewing affective pictures. The event‐related potentials (ERPs), systemic blood pressure, and pulse rate were also measured simultaneously.

RESULTS

The event‐related analysis of changes in oxy‐Hb for a 6 s‐picture presentation period showed that very unpleasant emotion was accompanied by an increase in oxy‐Hb in the bilateral ventrolateral PFCs, while very pleasant emotion was accompanied by a decrease in oxy‐Hb in the left dorsolateral PFC. There were no significant differences in either ERPs or autonomic nervous system activities between the two emotional states.

CONCLUSION

These findings suggest the possibility of recognizing patients’ emotions from CBF changes.

     

The Clinical and Radiological Spectrum of Posterior Reversible Encephalopathy Syndrome: A Retrospective Series of 24 Patients

ABSTRACT

BACKGROUND AND PURPOSE

Some patients with posterior reversible encephalopathy syndrome (PRES) present with atypical clinical and neuroimaging findings. The purpose of this study is to review the clinical and neuroimaging findings in patients diagnosed with PRES.

METHODS

We retrospectively included all patients diagnosed with PRES between January 2005 and March 2009. We reviewed demographic, clinical and laboratory data, neuroimaging findings, and prognosis.

RESULTS

Twenty‐four patients were included with a median age of 19 years. The clinical presentations included seizures (91.7%), headache (83.3%), visual disturbance (62.5%), encephalophathy (29.2%), and paralysis (8.3%). Co‐morbidities included systemic lupus erythematous (29.2%), kidney disease (20.8%), eclampsia (20.8%), renal artery stenosis (12.5%), Takayasu arteritis (4.2%), Sheehan's syndrome (4.2%), allergic purpura (4.2%), and acute intermittent porphyria (4.2%). Acute elevation of blood pressure was found in 22 patients (91.7%). Ten patients (41.7%) used steroids or immunosuppressants, three (12.5%) had acute renal failure before the symptoms. Atypical neuroimaging features included involvement of the frontal lobe (54.2%), basal ganglia (4.2%) or cortex (8.3%), and irreversible lesions (3/18, 16.7%).

CONCLUSIONS

A large proportion of patients with PRES may present with atypical neuroimaging findings. Apart from the known risk factors, such as hypertension, immunosuppressants, and renal failure of various etiologies may be the precipitants of PRES.

     

An entorhinal cortex sulcal pattern is associated with Alzheimer's disease

Objectives:

Magnetic resonance (MRI) studies rely on sulcal boundaries to delineate the human entorhinal cortex (EC) and typically show that EC size is reduced in Alzheimer's disease (AD) and a predictor of future dementia. However, it is unknown if variations in the EC sulcal patterns are associated with AD. We classified the lateral EC sulcal boundary as either a rhinal or collateral pattern and tested the hypotheses that the rhinal pattern was (1) more common in AD and (2) associated with a smaller EC size.

Experimental Design:

MRI was used to determine the prevalence of the rhinal and collateral EC patterns in 421 subjects (212 AD, 107 old normal (ONL), and 102 young NL (YNL). Anatomical validation studies of normal subjects were conducted at postmortem in 34 brain hemispheres and in vivo with 21 MRI volume studies. EC pattern reliability was studied with MRI in both cross‐sectional and longitudinal designs.

Principal Observations:

The rhinal pattern was more frequent in the right hemisphere in AD (47%) compared with ONL (28%, odds ratio = 2.25, P = 0.001). EC pattern was not related to ApoE genotype. The validations showed that the EC sulcal pattern was not associated with the neuronal number, surface area, or volume of the EC. In patients with antemortem MRI studied at postmortem it was equivalently determined, that EC patterns are reliably determined on MRI and do not change with the progressive atrophy of AD.

Conclusions:

The data indicate that the right hemisphere rhinal pattern is over represented in AD as compared with control. However, in normal subjects the EC rhinal pattern is not associated with a diminished EC tissue size. It remains to be demonstrated if the right EC rhinal sulcus pattern association with AD reflects genetic or developmental influences. Hum Brain Mapp, 2009. © 2008 Wiley‐Liss, Inc.

     

Depression and anxiety in chronic heart failure and chronic obstructive pulmonary disease: prevalence,relevance, clinical implications and management principles

Objective

To review evidence regarding the prevalence, causation, clinical implications, aspects of healthcare utilisation and management of depression and anxiety in chronic heart failure and chronic obstructive pulmonary disease.

Design

A critical review of the literature (1994–2009).

Findings

The prevalence of depression and anxiety is high in both chronic obstructive pulmonary disease (8–80% depression; 6–74% anxiety) and chronic heart failure (10–60% depression; 11–45% anxiety). However, methodological weaknesses and the use of a wide range of diagnostic tools make it difficult to reach a consensus on rates of prevalence. Co‐morbid depression and anxiety are associated with increased mortality and healthcare utilisation and impact upon functional disability and quality of life. Despite these negative consequences, the identification and management of co‐morbid depression and anxiety in these two diseases is inadequate. There is some evidence for the positive role of pulmonary/cardiac rehabilitation and psychotherapy in the management of co‐morbid depression and anxiety, however, this is insufficient to guide recommendations.

Conclusions

The high prevalence and associated increase in morbidity and mortality justifies future research regarding the management of anxiety and depression in both chronic heart failure and chronic obstructive pulmonary disease. Current evidence suggests that multi‐faceted interventions such as pulmonary and cardiac rehabilitation may offer the best hope for improving outcomes for depression and anxiety. Copyright © 2009 John Wiley & Sons, Ltd.

     

Quantification of head motion in children during various fMRI language tasks

Purpose:

Head motion during functional MRI scanning can lead to signal artifact, a problem often more severe with children. However, the documentation for the characteristics of head motion in children during various language functional tasks is very limited in the current literature. This report characterizes head motion in children during fMRI as a function of age, sex, and task.

Methods:

Head motion during four different fMRI language tasks was investigated in a group of 323 healthy children between the age of 5 and 18 years. A repeated measures ANOVA analysis was used to study the impact of age, sex, task, and the interaction of these factors on the motion.

Results:

Pediatric subjects demonstrated significantly different amounts of head motion during fMRI when different language tasks were used. Word‐Picture Matching, the only task that involved visual engagement, suffered the least amount of motion, which was significantly less than in any of the other three tasks; the latter were not significantly different from each other. Further examination revealed that the main effect of language task on motion was significantly affected by age, sex, and their interaction.

Conclusion:

Our results suggest that age, sex, and task are all associated with the degree of head motion in children during fMRI experiments. Investigators working with pediatric patients may increase their success by using task components associated with less motion (e.g., visual stimuli), or by using this large scale dataset to estimate the effects of sex and age on motion for planning purposes. Hum Brain Mapp 2009. © 2008 Wiley‐Liss, Inc.

     

Comparison of Partial (.6 mg/kg) versus Full‐Dose (.9 mg/kg) Intravenous Recombinant Tissue Plasminogen Activator Followed by Endovascular Treatment for Acute Ischemic Stroke: A Meta‐Analysis

ABSTRACT

BACKGROUND

In the treatment of acute ischemic stroke, intravenous (IV) recombinant tissue plasminogen (rt‐PA) and intraarterial (IA) interventions are often combined. However, the optimal dose of IV rt‐PA preceding endovascular treatment has not been established.

METHODS

Studies that used combined IV and IA thrombolysis were identified from a search of the MEDLINE, PubMed, and Cochrane databases. We compared the rates of angiographic recanalization, symptomatic intracerebral hemorrhage (sICH), and favorable functional outcome between patients who had been treated with .6 mg/kg IV rt‐PA and those who had received .9 mg/kg rt‐PA.

RESULTS

Eleven studies met our criteria. In 7 studies, .6 mg/kg IV rt‐PA had been administered to 317 patients, whereas 140 patients in 4 studies had received .9 mg/kg of IV rt‐PA. The weighted mean of median National Institutes of Health Stroke Scale score at presentation was 18.3 in the .6 mg/kg group (median range 9‐34), and 17.3 in the .9 mg/kg group (median range 4‐39). Patients in the .9 mg/kg group had higher rates of favorable outcome [odds ratio (OR) = 1.60, 95% confidence interval (CI) = (1.07‐2.40), P= .022] and similar rates of sICH [OR = .86 (95% CI .41‐1.83), P= .70]. Depending on the statistics used, the higher angiographic recanalization rate among patients treated with .9 mg/kg was significant (P= .03, events/trial syntax logistic regression) or borderline significant (P= .07, random effects model).

CONCLUSION

Our analysis suggests that using .9 mg/kg IV rt‐PA prior to IA thrombolysis is safe and may be associated with higher recanalization rates and better functional outcome at 3 months.

     

Changes in resting-state brain networks in writer's cramp

Objectives:

Writer's cramp (WC) is characterized by excessive cocontractions of agonist and antagonist hand and forearm muscles during writing. Changes in functional magnetic resonance imaging activation patterns in such conditions can be ambiguous as they might either reflect some aspect of the primary pathophysiological mechanism or, alternatively, may be the result of adaptive actions during task execution. To circumvent this problem, we examined WC patients during rest, i.e., without a task, using independent component analysis (ICA) applied to the blood oxygen level‐dependent time series.

Methods:

Functionally connected brain networks during rest were defined by ICA to assess differences between WC patients (n = 16) and healthy controls (n = 16). Analysis was carried out using FMRIB's Software Library.

Results:

Two functional networks showed between‐group differences, the sensorimotor network and the default‐mode network. In WC patients, the connectivity was reduced in the left postcentral area and increased in basal ganglia in contrast to healthy controls. These changes were not reversed after treatment with botulinum toxin.

Conclusions:

In line with other studies, the results show a dysfunction in cortico‐subcortical circuits in WC involving somatosensory cortex, areas interfacing the sensory and motor systems, and putamen contralateral to symptomatic hand. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.

     

Is transcranial sonography useful to distinguish scans without evidence of dopaminergic deficit patients from Parkinson's disease?

Background:

Approximately 10% of patients clinically diagnosed with early Parkinson's disease (PD) subsequently have normal dopaminergic functional imaging. Transcranial sonography (TCS) has been shown to detect midbrain hyperechogenicity in approximately 90% of Parkinson's disease (PD) patients and 10% of the healthy population. The aim of this study was to investigate the prevalence of midbrain hyperechogenicity in patients with suspected parkinsonism and scans without evidence of dopaminergic deficit (SWEDD), in comparison to PD patients.

Methods:

TCS was performed in 14 patients with SWEDD and 19 PD patients.

Results:

There was a significantly increased area of echogenicity in the PD group (0.24 ± 0.06 cm²), compared to the group of patients with SWEDD (0.13 ± 0.06 cm²; P < 0.001). One (9.1%) of these patients, compared to 14 (82.5%) of the PD patients, was found to have hyperechogenicity (P < 0.001).

Conclusions:

We conclude that TCS is useful to distinguish PD patients from patients with suspected parkinsonism and SWEDD. © 2012 Movement Disorder Society

     

Brain MRI Lesion Load at 1.5T and 3T versus Clinical Status in Multiple Sclerosis

ABSTRACT

BACKGROUND/PURPOSE

To assess correlation between brain lesions and clinical status with 1.5T and 3T magnetic resonance imaging (MRI).

METHODS

Brain MRI fluid‐attenuated inversion‐recovery (FLAIR) sequences were performed in 32 multiple sclerosis (MS) patients. Expanded Disability Status Scale (EDSS) score (mean ± standard deviation) was 2 ± 2.0 (range 0‐8), disease duration 9.3 ± 8.0 (range .8‐29) years.

RESULTS

FLAIR lesion volume (FLLV) at 3T was higher than at 1.5T (P= .01). Correlation between 1.5T FLLV and EDSS score was poor, while 3T FLLV correlated moderately and significantly (r_s= .39, P= .03). When controlling for age and depression, correlations between FLLV and cognitive measures were significant at 1.5T for the Judgment of Line Orientation test (JLO) (r_s=−.44, P= .05), the Symbol Digit Modalities Test (SDMT) (r_s=−.49, P= .02), and the California Verbal Learning Test Delayed Free Recall (CVLT DR) (r_s=−.44, P= .04). Correlations at 3T were also significant for these tests, but of greater magnitude: JLO (r_s=−.70, P= .0005), SDMT (r_s=−.73, P= .0001), CVLT DR (r_s=−.061, P= .003). Additional significant correlations obtained only at 3T included the 2 second‐paced auditory serial addition test (r_s=−.55, P= .01), the Brief Visuospatial Memory Test‐Delayed Free Recall (r_s=−.56, P= .007), and the California Verbal Learning Test Total Recall (r_s=−.42, P= .05).

CONCLUSION

MRI at 3T may boost sensitivity and improve validity in MS brain lesion assessment.

     

Using spaced retrieval and Montessori‐based activities in improving eating ability for residents with dementia

Objectives

To construct a training protocol for spaced retrieval (SR) and to investigate the effectiveness of SR and Montessori‐based activities in decreasing eating difficulty in older residents with dementia.

Methods

A single evaluator, blind, and randomized control trial was used. Eighty‐five residents with dementia were chosen from three special care units for residents with dementia in long‐term care facilities in Taiwan. To avoid any confounding of subjects, the three institutions were randomized into three groups: spaced retrieval, Montessori‐based activities, and a control group. The invention consisted of three 30–40 min sessions per week, for 8 weeks.

Results

After receiving the intervention, the Edinburgh Feeding Evaluation in Dementia (EdFED) scores and assisted feeding scores for the SR and Montessori‐based activity groups were significantly lower than that of the control group. However, the frequencies of physical assistance and verbal assistance for the Montessori‐based activity group after intervention were significantly higher than that of the control group, which suggests that residents who received Montessori‐based activity need more physical and verbal assistance during mealtimes. In terms of the effects of nutritional status after intervention, Mini‐Nutritional Assessment (MNA) in the SR group was significantly higher than that of the control group.

Conclusion

This study confirms the efficacy of SR and Montessori‐based activities for eating difficulty and eating ability. A longitudinal study to follow the long‐term effects of SR and Montessori‐based activities on eating ability and nutritional status is recommended. Copyright © 2010 John Wiley & Sons, Ltd.

     

Phasic muscle activity in sleep and clinical features of Parkinson disease

Objective

To determine whether amyloid deposition is associated with impaired neuropsychological (NP) performance and whether cognitive reserve (CR) modifies this association.

Methods

In 66 normal elderly controls and 17 patients with Alzheimer disease (AD), we related brain retention of Pittsburgh Compound B (PiB) to NP performance and evaluated the impact of CR using education and American National Adult Reading Test intelligence quotient as proposed proxies.

Results

We found in the combined sample of subjects that PiB retention in the precuneus was inversely related to NP performance, especially in tests of memory function, but also in tests of working memory, semantic processing, language, and visuospatial perception. CR significantly modified the relationship, such that at progressively higher levels of CR, increased amyloid deposition was less or not at all associated with poorer neuropsychological performance. In a subsample of normal controls, both the main effect of amyloid deposition of worse memory performance and the interaction with CR were replicated using a particularly challenging memory test.

Interpretation

Amyloid deposition is associated with lower cognitive performance both in AD patients and in the normal elderly, but the association is modified by CR, suggesting that CR may be protective against amyloid‐related cognitive impairment. ANN NEUROL 2010;67:353–364

     

Axonal pathways linked to therapeutic and nontherapeutic outcomes during psychiatric deep brain stimulation

Objective:

The underlying hypothesis of our work is that specific clinical neuropsychiatric benefits can be achieved by selective activation of specific axonal pathways during deep brain stimulation (DBS). As such, the goal of this study was to develop a method for identifying axonal pathways whose activation is most likely necessary for achieving therapeutic benefits during DBS.

Experimental design:

Our approach combined clinical data, diffusion tensor tractography, and computer models of patient‐specific neurostimulation to identify particular axonal pathways activated by DBS and determine their correlations with individual clinical outcome measures. We used this method to evaluate a cohort of seven treatment‐resistant depression patients treated with DBS of the ventral anterior internal capsule and ventral striatum (VC/VS).

Principal observations:

Clinical responders exhibited five axonal pathways that were consistently activated by DBS. All five pathways coursed lateral and medial to the VS or dorsal and lateral to the nucleus accumbens; however, details of their specific trajectories differed. Similarly, one common pathway was identified across nonresponders.

Conclusions:

Our method and preliminary results provide important background for studies aiming to expand scientific characterization of neural circuitry associated with specific psychiatric outcomes from DBS. Furthermore, identification of pathways linked to therapeutic benefit provides opportunities to improve clinical selection of surgical targets and stimulation settings for DBS devices. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.

     

Adenosine A2A receptor antagonist istradefylline (KW-6002) reduces "off" time in Parkinson's disease: a double-blind, randomized, multicenter clinical trial (6002-US-005)

Objective

Based on new understanding of nondopaminergic pathways involved in Parkinson's disease (PD) pathophysiology, a selective adenosine A_2A receptor antagonist, istradefylline, shows promise for the treatment of PD.

Methods

Istradefylline (40mg/day) was studied in levodopa‐treated PD subjects experiencing prominent wearing‐off motor fluctuations. At 23 North American sites, 196 subjects were randomized in a double‐blind, 12‐week outpatient clinical trial of istradefylline (114 completing the trial) or placebo (58 completing the trial). The primary efficacy measure was change from baseline to end point in the percentage of daily awake “off” time, recorded by subjects using a patient PD diary. Secondary end points evaluated “on” time (including “on time with dyskinesia”), the Unified Parkinson's Disease Rating Scale, and a Clinical Global Impression–Improvement of Illness score. Clinical laboratory, electrocardiograms, vital signs, and adverse event monitoring comprised the safety monitoring.

Results

After randomization, approximately 88% of subjects completed the double‐blind period. Compared with baseline, the decrease of daily awake “off” time for istradefylline was a mean (± standard deviation) of ?10.8 ± 16.6% (95% confidence interval, ?13.46 to ?7.52) and for placebo, ?4.0 ± 15.7% (95% confidence interval, ?7.73–0.31; p = 0.007 using two‐way analysis of variance). This effect corresponded to changes from baseline in total daily awake “off” time of ?1.8 ± 2.8 hours for istradefylline and ?0.6 ± 2.7 hours for placebo (p = 0.005). Treatment‐emergent adverse effects with istradefylline were generally mild.

Interpretation

Istradefylline was safe, well tolerated, and offered a clinically meaningful reduction in “off” time without increased troublesome dyskinesia. Ann Neurol 2008

     

Hemispheric specialization during mental imagery of brisk walking

Objectives:

Brisk walking, a sensitive test to evaluate gait capacity in normal and pathological aging such as parkinsonism, is used as an alternative to classical fitness program for motor rehabilitation and may help to decrease the risk of cognitive deterioration observed with aging. In this study, we aimed to identify brain areas normally involved in its control.

Methods:

We conducted a block‐design blood oxygen level dependent function magnetic resonance imaging (BOLD fMRI) experiment in 18 young healthy individuals trained to imagine themselves in three main situations: brisk walking in a 25‐m‐long corridor, standing or lying. Imagined walking time (IWT) was measured as a control of behavioral performance during fMRI.

Results:

The group mean IWT was not significantly different from the actual walking time measured during a training session prior to the fMRI study. Compared with other experimental conditions, mental imagery (MI) of brisk walking was associated with stronger activity in frontal and parietal regions mainly on the right, and cerebellar hemispheres, mainly on the left. Presumed imagined walking speed (2.3 ± 0.4 m/s) was positively correlated with activity levels in the right dorsolateral prefrontal cortex and posterior parietal lobule along with the vermis and the left cerebellar hemisphere.

Interpretations:

A new finding in this study is that MI of brisk walking in young healthy individuals strongly involves processes lateralized in right fronto‐parietal regions along with left cerebellum. These results show that brisk walking might be a non automatic locomotor activity requiring a high‐level supraspinal control. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.

     

Disorder‐specific dysfunction in right inferior prefrontal cortex during two inhibition tasks in boys with attention‐deficit hyperactivity disorder compared to boys with obsessive–compulsive disorder

Background:

Inhibitory dysfunction is a key behavioral and cognitive phenotype of attention‐deficit hyperactivity disorder (ADHD) and obsessive–compulsive disorder (OCD). Both disorders show neuropsychological deficits and fronto‐striatal dysfunction during tasks of motor response inhibition and cognitive flexibility. This study investigates differences and commonalities in functional neural networks mediating inhibitory control between adolescents with ADHD and those with OCD to identify disorder‐specific neurofunctional markers that distinguish these two inhibitory disorders.

Methods:

Event‐related fMRI was used to compare brain activation between 20 healthy boys, 18 (Stop task) or 12 boys (Switch task) with ADHD, and 10 boys with OCD during a tracking Stop task that measures inhibition and stopping failure and during a visual–spatial switching task measuring cognitive flexibility.

Results:

Both patient groups shared brain dysfunction compared to healthy controls in right orbitofrontal (successful inhibition) and left dorsolateral prefrontal cortices (failed inhibition). Right inferior prefrontal dysfunction, however, was disorder‐specific to ADHD during both tasks. Left inferior prefrontal dysfunction during the Switch task was significant in children with ADHD relative to controls, but only reached a trend in patients with OCD. Patients with ADHD furthermore showed disorder‐specific dysfunction in left basal ganglia and cingulate gyrus during the Switch task.

Conclusions:

Patients with ADHD compared to those with OCD have both common and distinct dysfunctions during inhibitory control. The most consistently reported functional abnormality in children with ADHD in right inferior prefrontal cortex during inhibitory control appears to be disorder‐specific when compared to patients with OCD and may be a specific neurofunctional biomarker of ADHD. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.

     

Advanced time‐series analysis of MEG data as a method to explore olfactory function in healthy controls and Parkinson's disease patients

Objectives:

To determine whether time‐series analysis of magnetoencephalography (MEG) data is a suitable method to study brain activity related to olfactory information processing, and to detect differences in odor‐induced brain activity between patients with Parkinson's disease (PD) and controls.

Methods:

Whole head 151‐channel MEG recordings were obtained in 21 controls and 20 patients with PD during a 10‐min olfactory stimulus paradigm, consisting of 10 alternating rest‐stimulus cycles (30 s each), using phenylethyl alcohol administered by means of a Burghart olfactometer. Relative spectral power and synchronization likelihood (SL; an unbiased measure of functional connectivity) were calculated for delta, theta, alpha1, alpha2, beta, and gamma frequency bands.

Results:

In controls, olfactory stimulation produced an increase in theta power and a decrease in beta power. In patients with PD, there was a decrease in alpha1 power. No significant interaction between group and condition was found for spectral power. SL analysis revealed a significantly different response to olfactory stimulation in patients with PD compared to controls. In controls, the odor stimulus induced a decrease in local beta band SL. The response in patients with PD involved a decrease in intrahemispheric alpha2 band SL.

Conclusion:

This is the first study to show that time‐series analysis of MEG data, including spectral power and SL, can be used to detect odor‐induced changes in brain activity. In addition, differences in odor‐induced brain activity were found between patients with PD and controls using analysis of SL, but not of spectral power. Hum Brain Mapp 2009. © 2009 Wiley‐Liss, Inc.

     

Correlation study of optimized voxel-based morphometry and (1)H MRS in patients with mesial temporal lobe epilepsy and hippocampal sclerosis

Purpose:

To assess whether structural and metabolic brain abnormalities are correlated in MTLE/HS syndrome.

Methods:

Optimized voxel‐based morphometry (VBM) of gray matter concentration (GMC) and gray matter volume (GMV) and proton magnetic resonance spectroscopy measurements from both‐sided hippocampal and thalamic regions were performed in 20 MTLE/HS patients and 20 sex‐ and age‐matched healthy controls. The local GMC and GMV values were calculated in both the affected and unaffected hippocampi and ipsilateral and contralateral thalami in patients and healthy subjects, and these were compared. VBM variables and NAA, NAA/Cr and NAA/(Cr+Cho) values from the investigated brain regions were correlated.

Results:

(1) Analysis revealed significantly more extensive GMV reduction than GMC reduction in patients' affected hippocampus. In addition, significant GMV reduction was observed in the ipsilateral thalamus in MTLE/HS patients. (2) Significant decreases in all VBM and MRS variables were revealed in the affected hippocampus. Whilst practically normal GMC values were revealed in patients' both‐sided thalamic regions, a significant decrease in local GMV and metabolic measurements were found in the patients' ipsilateral thalamus. (3) Pearson's correlations between structural and metabolic abnormalities were significant for the ipsilateral thalamus only.

Conclusion:

Structural and metabolic abnormalities as detected by optimized voxel‐based morphometry and ¹H MRS in hippocampal and thalamic regions are only partially correlated in MTLE/HS patients. It seems therefore reasonable that both methods reflect different aspects of brain pathology, which, at least to some degree, might be independently ongoing. Hum Brain Mapp 2009. © 2008 Wiley‐Liss, Inc.

     

Simultaneous EMG-functional MRI recordings can directly relate hyperkinetic movements to brain activity

Objective:

To apply and validate the use of electromyogram (EMG) recorded during functional magnetic resonance imaging (fMRI) in patients with movement disorders, to directly relate involuntary movements to brain activity.

Methods:

Eight “familial cortical myoclonic tremor with epilepsy” (FCMTE) patients, with tremor‐like cortical myoclonus and cerebellar Purkinje cell degeneration, and nine healthy controls performed hand posture and movement in an on/off fashion (block design). Superfluous movements were quantified as deviations in EMG power, positive and negative, with respect to the average EMG per session. This measure, “residual EMG” (r‐EMG), was derived by Gram–Schmidt orthogonalization. Activation maps resulting from conventional block regressors and novel r‐EMG regressors were compared.

Results:

In healthy participants, the block posture regressor identified mainly cerebellar activity and some activity in other areas belonging to motor circuitry. In FCMTE patients, no cerebellar activity was seen with the block posture regressor, compatible with cerebellar Purkinje cell changes in FCMTE. EMG power showed little variation during posture in healthy controls. Therefore, the r‐EMG regressor was almost constant and revealed no brain activity as expected. In contrast, in FCMTE patients the r‐EMG posture regressor was highly variable due to continuous myoclonic jerks. It identified sensorimotor cortical areas, compatible with cortical hyperexcitability in FCMTE patients.

Conclusion:

Conventional block regressors can be used to identify neuronal circuitry associated with a specific motor task, whereas r‐EMG regressors can help identify brain activation directly related to involuntary movements. Simultaneous EMG‐fMRI is complementary to conventional fMRI and will facilitate studies of hyperkinetic movement disorders. Hum Brain Mapp 2008. © 2007 Wiley‐Liss, Inc.

     

Hippocampal atrophy patterns in mild cognitive impairment and Alzheimer's disease

Background:

Histopathological studies and animal models suggest that hippocampal subfields may be differently affected by aging, Alzheimer's disease (AD), and other diseases. High‐resolution images at 4 Tesla depict details of the internal structure of the hippocampus allowing for in vivo volumetry of different subfields. The aims of this study were as follows: (1) to determine patterns of volume loss in hippocampal subfields in normal aging, AD, and amnestic mild cognitive impairment (MCI). (2) To determine if measurements of hippocampal subfields provide advantages over total hippocampal volume for differentiation between groups.

Methods:

Ninety‐one subjects (53 controls (mean age: 69.3 ± 7.3), 20 MCI (mean age: 73.6 ± 7.1), and 18 AD (mean age: 69.1 ± 9.5) were studied with a high‐resolution T2 weighted imaging sequence aimed at the hippocampus. Entorhinal cortex (ERC), subiculum, CA1, CA1‐CA2 transition zone (CA1‐2), CA3 & dentate gyrus (CA3&DG) were manually marked in the anterior third of the hippocampal body. Hippocampal volume was obtained from the Freesurfer and manually edited.

Results:

Compared to controls, AD had smaller volumes of ERC, subiculum, CA1, CA1‐2, and total hippocampal volumes. MCI had smaller CA1‐2 volumes. Discriminant analysis and power analysis showed that CA1‐2 was superior to total hippocampal volume for distinction between controls and MCI.

Conclusion:

The patterns of subfield atrophy in AD and MCI were consistent with patterns of neuronal cell loss/reduced synaptic density described by histopathology. These preliminary findings suggest that hippocampal subfield volumetry might be a better measure for diagnosis of early AD and for detection of other disease effects than measurement of total hippocampus. Hum Brain Mapp, 2010. © 2010 Wiley‐Liss, Inc.

     

Recurrent spreading depolarizations after subarachnoid hemorrhage decreases oxygen availability in human cerebral cortex

Objective

Delayed ischemic neurological deficit (DIND) contributes to poor outcome in subarachnoid hemorrhage (SAH) patients. Because there is continuing uncertainty as to whether proximal cerebral artery vasospasm is the only cause of DIND, other processes should be considered. A potential candidate is cortical spreading depolarization (CSD)‐induced hypoxia. We hypothesized that recurrent CSDs influence cortical oxygen availability.

Methods

Centers in the Cooperative Study of Brain Injury Depolarizations (COSBID) recruited 9 patients with severe SAH, who underwent open neurosurgery. We used simultaneous, colocalized recordings of electrocorticography and tissue oxygen pressure (p_tiO₂) in human cerebral cortex. We screened for delayed cortical infarcts by using sequential brain imaging and investigated cerebral vasospasm by angiography or time‐of‐flight magnetic resonance imaging.

Results

In a total recording time of 850 hours, 120 CSDs were found in 8 of 9 patients. Fifty‐five CSDs (∼46%) were found in only 2 of 9 patients, who later developed DIND. Eighty‐nine (∼75%) of all CSDs occurred between the 5th and 7th day after SAH, and 96 (80%) arose within temporal clusters of recurrent CSD. Clusters of CSD occurred simultaneously, with mainly biphasic CSD‐associated p_tiO₂ responses comprising a primary hypoxic and a secondary hyperoxic phase. The frequency of CSD correlated positively with the duration of the hypoxic phase and negatively with that of the hyperoxic phase. Hypoxic phases significantly increased stepwise within CSD clusters; particularly in DIND patients, biphasic p_tiO₂ responses changed to monophasic p_tiO₂ decreases within these clusters. Monophasic hypoxic p_tiO₂ responses to CSD were found predominantly in DIND patients.

Interpretation

We attribute these clinical p_tiO₂ findings mainly to changes in local blood flow in the cortical microcirculation but also to augmented metabolism. Besides classical contributors like proximal cerebral vasospasm, CSD clusters may reduce O₂ supply and increase O₂ consumption, and thereby promote DIND. ANN NEUROL 2010;67:607–617