Spontaneous gamma coherence as a possible trait marker of schizophrenia-An explorative study.

OBJECTIVES: Integration of sensory information by cortical network binding appears to be crucially involved in sensory processing activity. Studies in schizophrenia using functional neuroimaging, event-related potentials and EEG coherence indicate an impairment of cortical network coupling in this disorder. Previous electrophysiological investigations in animals and humans suggested that gamma activity (oscillations at around 30-100Hz) is essential for cortical network binding. This is the first investigation of spontaneous gamma activity in schizophrenics and their first degree relatives as compared to normal controls. METHOD: Resting EEG was recorded in 20 drug naïve/drug free male schizophrenic patients, their pair matched male first degree relatives and 20 age-, sex-, education- and handedness-matched normal controls. Power spectrum and coherence of gamma band activity was analysed using MATLAB 6.5. RESULTS: Schizophrenic patients had significantly less interhemispheric spontaneous gamma coherence and increased gamma power compared to normal controls. But there was no significant difference in gamma coherence between patients and their first degree relatives. Spontaneous gamma coherence had significant correlation with few PANSS subscale scores. CONCLUSIONS: There is cortical hyperactivation and a reduced spontaneous and induced gamma coherence abnormality in schizophrenia. The abnormal gamma coherence appears explaining the psychopathology and poor performance on cognitive task in schizophrenia. This study has also generated hypotheses that the gamma band abnormality may be a trait abnormality in schizophrenics as seen by the similarity between the patient and their clinically asymptomatic first degree relatives.

A study of contingent negative variation and post-imperative negative variation: search for state and trait electrophysiological markers in schizophrenia.

OBJECTIVE: To compare event-related potential measures, contingent negative variation and post-imperative negative variation in drug-naïve or drug-free schizophrenic patients and normal healthy controls, and to study the effect of antipsychotic medication on the above measures. METHODS: A hospital-based prospective study was conducted at Central Institute of Psychiatry, Ranchi, India. The sample constituted 31 drug-naïve or drug-free patients with schizophrenia and 31 normal healthy individuals, matched for age and gender. An S1-S2 paradigm was used, in which the warning stimulus (S1) was auditory and the target stimulus or imperative stimulus (S2) was visual. The early contingent negative variation was marked at 500 milliseconds after S1, and late contingent negative variation was marked as the negative wave just prior to S2. The post-imperative negative variation was measured as the continued negativity after S2. RESULTS: Drug-naïve and drug-free patients significantly differed from the controls on amplitudes of early and late contingent negative variations, as well as on latency of late contingent negative variation. The rate for correct classification in 80% of cases (Wilks' lambda = 0.76) was observed in measuring amplitude of late contingent negative variation only. After exposure to antipsychotic drugs, the late contingent negative variation amplitude was found to normalise in the patient group. CONCLUSION: The late contingent negative variation could be considered a state marker for schizophrenia.

The behavioural profile of psychiatric disorders in persons with intellectual disability.

BACKGROUND: Problems associated with psychiatric diagnoses could be minimized by identifying behavioural clusters of specific psychiatric disorders. METHODS: Sixty persons with intellectual disability (ID) and behavioural problems, aged 12-55 years, were assessed with standardized Indian tools for intelligence and adaptive behaviour. Clinical diagnoses were conferred as per International Classification of Diseases - 10th Revision (ICD-10) criteria. Subsequently Reiss Screen for Maladaptive Behaviors (RSMB) and AAMD Adaptive Behavior Scale-Part II were administered independently. RESULTS: Aggression and rebellious behaviours were more common in affective disorders and personality disorders. Psychotic and paranoid features were significantly more in psychosis group. Those with behavioural problems had significantly low scores on the sub-scales of RSMB. CONCLUSION: RSMB and AAMD Adaptive Behavior Scale-Part II will be useful to identify behavioural clusters, which will complement clinical psychiatric diagnoses in individuals with ID.

Psychiatric diagnosis in persons with intellectual disability in India.

BACKGROUND: This study examines the rate of psychiatric diagnosis as per ICD-10 and Reiss Screen for Maladaptive Behaviours (RSMB), and distribution of psychiatric diagnosis with regard to the severity of intellectual disability (ID). It also explores the degree of agreement between Reiss screen and clinical diagnosis (ICD-10) in relation to dual diagnosis. METHODS: In this study Intelligence (IQ) and Social Quotient (SQ) were estimated on Indian adaptation of Binet's scale and Vineland Social Maturity Scales, respectively, in 60 consecutive persons with ID. Both ICD-10 and RSMB were used independently to determine the presence of psychiatric diagnosis. RESULTS: Clinically, according to ICD-10, about 60% of the sample was found to have dual diagnosis as compared to 48% on RSMB. Agreement between ICD-10 and RSMB about psychiatric comorbidity was 82%. Commonest psychiatric diagnosis was unspecified psychosis followed by bipolar affective disorders. CONCLUSION: Persons with ID do suffer from various psychiatric disorders. RSMB is a useful tool for differentiating between psychiatric problems and maladaptive behaviours. Hence RSMB can be used in the Indian context.

Childhood leukodystrophy presenting as secondary bipolar disorder.

Leukodystrophies are rare dysmyelinating disorders of the nervous system, which occasionally have an initial psychiatric presentation. This report describes a case of a 9-year-old boy whose initial presentation resembled a bipolar disorder but subsequent work-up revealed an underlying leukodystrophy, most likely Alexander's disease. The course of this rare disease along with the implications of making a diagnosis of leukodystrophy in a psychiatric setting is discussed.

Post-encephalitic Kluver-Bucy syndrome.

Kluver-Bucy syndrome is a rare amalgamation of neurobehavioural signs and symptoms seen infrequently in humans following insult to bilateral temporal lobes. This report presents a case which along with emerging symptoms of Kluver-Bucy syndrome, developed Attention-Deficit/Hyperactivity Disorder (ADHD) consequent to viral encephalitis. The case highlights the presentation and management of this syndrome in a six-year-old girl with primary focus on the implications of Kluver-Bucy symptoms in current clinical practice involving neurobehavioural syndromes in children.

Decomposition of posterior alpha rhythm.

The classical posterior alpha rhythm has been decomposed into regular and irregular components using orthogonal transformation. A periodicity generator is considered, which has three characteristic control parameters: the periodicity, the amplitudes or scaling factors and the pattern associated with successive periodic segments. The regular component is shown to be equivalent to an oscillator or periodicity generator whose parameters are dynamically varying and, thus, producing both amplitude- and frequency-modulation. The irregular component is devoid of such modulating behavior. Electroencephalogram signals from normal, maniac and epileptic subjects are studied. Through analytic signal-based analysis, it is shown that for the regular component, healthy brain possesses universal scaling behavior, whereas heterogeneous scaling or absence of universality is observed for the diseased brain.

Subdural hygroma presenting as dementia with kluver-bucy symptoms.

Dementia is not an uncommon presentation in psychiatric practice. Of the various causes of reversible dementia, subdural hygroma is a lesser-known potentially reversible cause. A case of dementia with Kluver-Bucy symptoms secondary to subdural hygroma is described and implications of Kluver-Bucy symptoms in dementia are discussed.

Fluoxetine induced extrapyramidal symptoms : case reports.

This case report describes the induction of extrapyramidal symptoms with fluoxetine, which is reported to be a rare phenomenon. A dopamine blockade at the nigrostriatal level primarily mediated by serotonin has been proposed as the probable mechanism.

Comparative study of clinical effectiveness of luria-nebraska neuropsychological battery, EEG and ct scan in brain damaged patients.

The clinical effectiveness and concurrent validity of Luria-Nebraska Neuropsychological Battery (LNNB) was assessed in a sample of 30 brain-damaged and 30 non-patient, normal control subjects. Both the groups were matched for age, sex and education. There were highly significant differences between the mean scale scores of the two groups on all LNNB clinical scales. Brain damaged patients did poorer than normal controls. The LNNB had a hit rate of86.66% in diagnosing brain-damaged patients in comparison to 70% and 52% of EEG and CT scan respectively. The three measures were found to be significantly correlated with each other. The LNNB was found to be an effective instrument for neuropsychological assessment.

Transsexulism : onset after an acute psychotic episode.

Transsexualism is a rare disorder with an uncertain aetiology. Recently, biological factors have been considered to be important in its occurrence. The relationship of transsexualism with psychosis is not known; in most cases no specific relationship exists, though few cases of symptomatic transsexualism have been reported. In the following case, cross dressing and homosexual orientation was present from an early age, but gender dysphoria became manifest only after the onset of an acute psychotic episode. The implications of such a finding are discussed.