P. N. Jayakumar

Gray matter volume abnormalities and externalizing symptoms in subjects at high risk for alcohol dependence.

Reduced right amygdala volumes have been reported in young, alcohol‐naïve subjects at high risk (HR) for alcohol dependence. The differences in brain morphometry have been associated with an excess of externalizing behaviors in these subjects. This may reflect a neurobiological vulnerability to alcohol dependence. Existing Magnetic Resonance Imaging (MRI) studies on these subjects have examined only a few, pre‐selected brain regions using the manual regions of interest (ROI) approach. MRI of HR subjects (n = 20) and age, sex, and handedness‐matched low‐risk (LR) subjects (n = 21) were analyzed using optimized voxel‐based morphometry and ROI approach. The externalizing symptoms of these subjects and their fathers were measured using the Semi‐Structured Assessment for the Genetics of Alcoholism. HR subjects had significantly smaller volumes of superior frontal, cingulate and parahippocampal gyri, amygdala, thalamus and cerebellum. These gray matter volumes correlated negatively with externalizing symptoms scores. Subjects at HR for alcoholism have reduced volumes of critical areas of brain gray matter, which are associated with increased externalizing symptoms. These represent key endophenotypes of alcoholism.

Cerebrovascular disease in children.

Stroke although rare in children, is an important cause of morbidity in the paediatric age group. Over a period of 8 years, 43 children (17 boys and 26 girls) in the age groups of 1–16 years (mean 8.02 yrs) presented with stroke which constituted 10% of all strokes in the young and 0.7% of all paediatric admissions. The chief clinical features were hemiplegia (86%), convulsions (27%), fever (23%). dysphasia (23%), headache (11%) and altered level of consciousness (11%). Routine laboratory tests were non‐contributory. Cranial computerized tomography (CCT) on 21 patients was abnormal in 95% and was useful in revealing the extent of infarction. Infarction was confined to middle cerebral artery territory, often involving basal ganglionic structures and was associated with focal or diffuse atrophy. Angiograms were abnormal in 78% of the patients (18/23) and were complimentary to the CCT. Etiological factors identified were: Moya‐moya disease 6, arteritis 5, fibromuscular dysplasia 2, scorpion sting 2, and venous sinus thrombosis and small vessel occlusion one each. Though 23% of the patients had fever at onset, no obvious evidence of systemic or CNS infection was noticed. Stroke in children continues to pose a diagnostic challenge.

Automated MRI parcellation study of regional volume and thickness of prefrontal cortex (PFC) in antipsychotic-naïve schizophrenia.

Objective:  Prefrontal cortical dysfunction is considered to be critical in the pathogenesis of schizophrenia. However, structural magnetic resonance imaging (MRI) studies on the PFC have yielded inconsistent results because of various confounding factors.

Neurological soft signs in never-treated schizophrenia

Objective: Studies of Neurological Soft Signs (NSS) in schizophrenia are confounded by handedness, inconsistent methodology, and prior treatment with neuroleptics. The study objective is to examine NSS in never‐treated schizophrenia.

Corpus callosum abnormalities associated with greater externalizing behaviors in subjects at high risk for alcohol dependence

Subjects at high risk for alcoholism have a greater propensity for externalizing behaviors and brain volume reductions of possible neurodevelopmental origin. Morphometric deficits in the corpus callosum (CC), which might reflect this neurodevelopmental abnormality, have been reported in other externalizing disorders such as attention deficit hyperactivity disorder, but not in subjects at high risk for alcoholism. The objective of the current study was to evaluate the CC morphometry in subjects at high risk for alcoholism. Magnetic resonance images of the CC in high-risk subjects (n=20) were compared with those of low-risk subjects matched to the high-risk subjects for age, sex, and handedness (n=20). Mid-sagittal areas of the CC, genu, body, isthmus and splenium were measured based on Witelsons method with good inter- and intra-rater reliability. Externalizing behaviors were assessed using the Semi-Structured Assessment for Genetics of Alcoholism-II. Total CC, genu and isthmus areas were significantly smaller in high-risk than low-risk subjects after controlling for age and intracranial area. The total externalizing symptoms score had a significant negative correlation with genu and isthmus areas. Smaller CC areas and their negative association with externalizing behaviors may represent yet another marker of susceptibility to alcoholism in high-risk subjects.

Gray matter volume deficits in spinocerebellar ataxia: An optimized voxel based morphometric study ☆

INTRODUCTION Spinocerebellar ataxias (SCA) are a group of autosomal dominant ataxias with varied clinical phenotypes. However there are no unique distinguishing features on routine neuroimaging among the various genetically defined SCAs. Voxel-based morphometry (VBM) provides an automated unbiased analysis of structural MRI scans and gives a comprehensive assessment of anatomical differences throughout the brain. OBJECTIVES The aims of this study were to (i) characterize the patterns of atrophy in SCA1, SCA2 and SCA3 using optimized VBM, (ii) demonstrate the characteristic anatomical differences in these genetically distinct SCA subtypes, and (iii) assess the relationship between morphometric measures and the CAG repeat lengths and other attributes of the disease. METHODS Thirty-one genetically confirmed patients suffering from SCA (SCA1 - 12, SCA2 - 9, and SCA3 - 10) were studied. High resolution T1-weighted 3-Dimensional Magnetic Resonance Images of 31 patients were analyzed using the optimized VBM procedure. RESULTS In all the three SCAs there was a significant loss of gray matter in both cerebellar hemispheres and vermis. Vermian atrophy was more pronounced in SCA3, while SCA1 and SCA2 had significant white matter atrophy. Pontine white matter atrophy was more pronounced in SCA2. In SCA1, the severity of ataxia strongly correlated with the degree of gray matter atrophy in cerebellar hemispheres. The duration of symptoms and lengths of CAG repeats had no correlation with the degree of atrophy. CONCLUSIONS This study showed that the different subtypes of SCAs may have morphometric differences in the cerebellum, brainstem and the supratentorial structures.

Schneiderian first rank symptoms and inferior parietal lobule cortical thickness in antipsychotic-naïve schizophrenia

Inferior parietal lobule (IPL) is implicated in the pathogenesis of first rank symptoms (FRS) in schizophrenia by functional neuroimaging studies. However, the relationship between IPL cortical thickness and FRS is yet to be explored. In this study, cortical thickness of IPL was analyzed in antipsychotic-naïve schizophrenia patients (total number = 51) with [FRS(+); N = 25] and those without FRS [FRS(-); N = 26] in comparison with group-matched healthy controls (N = 47). FRS(+) patients showed significant cortical thickness deficit in right IPL (specifically angular gyrus) in comparison with both FRS(-) patients (p = 0.005) and healthy controls (p = 0.0002); lack of difference on the left side might possibly be related to larger variance in healthy controls. Deficient cortical thickness involving IPL in FRS(+) schizophrenia patients adds further support to the role of internal monitoring system in the pathogenesis of FRS in schizophrenia.

MRI volumetric and 31P MRS metabolic correlates of caudate nucleus in antipsychotic‐naïve schizophrenia

Objective:  To examine the volumetric and metabolic correlates of caudate nucleus in antipsychotic‐naïve schizophrenia patients in comparison with healthy controls.

Clinicoradiological features of tuberculous meningitis in patients over 50 years of age

Background and aim: Tuberculous meningitis (TBM) is a debilitating form of CNS tuberculosis with a high morbidity and mortality in spite of treatment. The diagnosis is based on clinical, radiological and laboratory features. The classical CT features of basal exudates, hydrocephalus, infarcts and granulomas have been mostly reported in younger individuals. Our aim was to study imaging features of TB meningitis in adults over the age of 50 years. Materials and methods: Clinical, imaging and laboratory features of 53 adult patients over the age of 50 years (sixth to eighth decades) were studied retrospectively. Diagnosis of TBM was based on clinical and laboratory features. Results: Imaging features were the conspicuous absence of typical features of TBM (ie, basal meningeal enhancement, hydrocephalus, infarcts/granulomas were seen in only a minority of patients). Conclusions: CT features of TBM in elderly patients were few, atypical and non-contributory for diagnosis, probably because of age related immune senescence. Strong clinical suspicion and correlation with laboratory findings is necessary for early diagnosis.

High energy phosphate abnormalities normalize after antipsychotic treatment in schizophrenia: a longitudinal 31P MRS study of basal ganglia.

We reported increased high-energy phosphate metabolism in the basal ganglia of antipsychotic-naïve schizophrenia patients using (31)P Magnetic Resonance Spectroscopy (MRS). These patients were followed up for 1 year and and reassessed using (31)P MRS. Fourteen (8 males) patients with DSM-IV schizophrenia and 14 (11 males) healthy controls underwent (31)P MRS of sub-cortical structures (predominantly basal ganglia) twice (mean+/-S.D. interscan interval 1.15+/-0.17year) on a 1.5T scanner. Total scores on the Positive and Negative Syndrome Scale (PANSS) decreased significantly after treatment in schizophrenia patients. Patients had significantly lower mean PCr/ATP ratios than healthy controls at baseline but not during the follow-up. In patients, there was a significant positive correlation between the magnitude of improvement in PANSS total scores and the extent of change in the PCr/ATP ratio. Findings support the hypothesis that reduction of energy demand or induction of decreased energy-demanding processes might underlie the mechanism of action of antipsychotics in schizophrenia.