Sai Krishna Tikka

Evaluation of resting state gamma power as a response marker in schizophrenia

An abnormal activity in the electroencephalography (EEG) gamma band (>30 Hz) has been demonstrated in schizophrenia and this has been suggested to be reflecting a deficit in the development and maturation of the basic cognitive functions of attention, working memory and sensory processing. Hypothesizing gamma oscillatory activity as a potential EEG biomarker to antipsychotic response in schizophrenia, the present study aimed at measuring baseline spontaneous gamma activity in schizophrenia patients, and evaluating its response to antipsychotic treatment over 8 weeks.

Increased spontaneous gamma power and synchrony in schizophrenia patients having higher minor physical anomalies.

The higher frequency of minor physical anomalies (MPAs) in schizophrenia provides morphological evidence for the neurodevelopmental theory. Abnormal gamma oscillations (>30 Hz) seen in the electroencephalogram (EEG) in schizophrenia have been hypothesized to result from developmental insults. This study investigated spontaneous gamma oscillations in schizophrenia patients having higher and lower number of MPAs. Forty drug naïve/free schizophrenia patients and 20 matched healthy controls were assessed for MPAs on the Extended Waldrop Scale (EWS). All participants underwent an awake, resting 192-channel EEG recording. Spontaneous gamma spectral power and coherence were estimated in the low- (30-50 Hz) and high-gamma (51-70 and 71-100 Hz) bands. Significantly higher power was observed in high-MPA than healthy control group in low-gamma band over right frontal, parietal and temporal regions. Spectral power in the high-gamma band (71-100 Hz) was also significantly higher in the high-MPA schizophrenia subgroup than in the healthy control group over left frontal, parietal and temporal regions. Additionally, regional intra-hemispheric and inter-hemispheric coherence in the low-gamma band was significantly higher in the high-MPA schizophrenia subgroup than on the healthy control group. This study is the first to provide evidence of increased spontaneous gamma power and synchrony in schizophrenia patients having higher MPAs, supporting the idea that it may represent a distinct subgroup of schizophrenia with a neurodevelopmental basis.

Psychiatry and music

Vocal and/or instrumental sounds combined in such a way as to produce beauty of form, harmony and expression of emotion is music. Brain, mind and music are remarkably related to each other and music has got a strong impact on psychiatry. With the advent of music therapy, as an efficient form of alternative therapy in treating major psychiatric conditions, this impact has been further strengthened. In this review, we deliberate upon the historical aspects of the relationship between psychiatry and music, neural processing underlying music, musics relation to classical psychology and psychopathology and scientific evidence base for music therapy in major psychiatric disorders. We highlight the role of Indian forms of music and Indian contribution to music therapy.

The efficacy of cerebellar vermal deep high frequency (theta range) repetitive transcranial magnetic stimulation (rTMS) in schizophrenia: A randomized rater blind-sham controlled study

Repetitive transcranial magnetic stimulation (rTMS) is a promising therapeutic for schizophrenia. Treatment effects of rTMS have been variable across different symptom clusters, with negative symptoms showing better response, followed by auditory hallucinations. Cerebellum, especially vermis and its abnormalities (both structural and functional) have been implicated in cognitive, affective and positive symptoms of schizophrenia. rTMS to this alternate site has been suggested as a novel target for treating patients with this disorder. Hypothesizing cerebellar vermal magnetic stimulation as an adjunct to treat schizophrenia psychopathology, we conducted a double blind randomized sham controlled rTMS study. In this study, forty patients were randomly allocated (using block randomization method) to active high frequency (theta patterned) rTMS (n=20) and sham (n=20) groups. They received 10 sessions over 2 weeks. The Positive and Negative Syndrome Scale (PANSS) and Calgary Depression Scale for Schizophrenia (CDSS) scores were assessed at baseline, after last session and at 4 weeks (2 weeks post-rTMS). We found a significantly greater improvement in the group receiving active rTMS sessions, compared to the sham group on negative symptoms, and depressive symptoms. We conclude that cerebellar stimulation can be used as an effective adjunct to treat negative and affective symptoms.

Schneiderian First Rank Symptoms and Gamma Oscillatory Activity in Neuroleptic Naïve First Episode Schizophrenia: A 192 Channel EEG Study

Objective Schneiderian first-rank symptoms (FRS) and abnormal EEG gamma activity in schizophrenia have been reported independently to have a neurodevelopmental basis. We aimed to investigate spontaneous gamma power in two groups of first episode schizophrenia patients (those who experience FRS and those who do not). Methods A comparative hospital based study having 37neuroleptic naïve male patients with schizophrenia divided into two groups-FRS(+) and FRS(-) groups based on the presence of FRS. Thirty age, sex, education and handedness matched individuals served as controls (N). All participants underwent a 192-channel resting Electroencephalography (EEG) recording. Gamma spectral power was calculated for low- (30-50 Hz) and high-gamma 1 & 2 (51-70 and 71-100 Hz) bands. Spectral power was compared between three groups using MANOVA and supplementary one-way ANOVA with Bonferroni test controlling for multiple comparisons. Linear regression was used to identifying predictor variables for FRS. Pearson correlation coefficient was computed between spectral power parameters and various clinical variables. Results Significantly higher high gamma band-1 power was observed over right frontal (p<0.05), parietal (p<0.05) and temporal (p<0.05) regions in FRS(+) than FRS(-) group and normal controls. Right parietal high gamma-1 power and paranoid cluster on PANSS significantly predicted number of FRS in total schizophrenia patients; paranoid cluster on PANSS showed significant correlation with number of FRS in FRS(+) group. Conclusion Findings of our study add to the evidence that areas contained within the hetero modal association cortex are associated with FRS. The study findings also strengthen the neurodevelopmental basis of FRS in schizophrenia.

Resting state theta band source distribution and functional connectivity in remitted schizophrenia.

Increased resting theta activity is one consistent observation occurring during all the phases of schizophrenia. However, the resting theta oscillations during the remission phase are yet unclear. We studied resting theta current source density and functional connectivity in remitted schizophrenia and compared with healthy controls. Significantly increased current source density was found in the dominant anterior cingulate cortex. Increased connectivity between the inferior parietal lobe bilaterally and between the left inferior parietal lobe and right middle frontal gyrus was also found. It may be concluded that schizophrenia patients have aberrant regional theta band current source density and functional connectivity even during remission.

Evaluation of spontaneous dense array gamma oscillatory activity and minor physical anomalies as a composite neurodevelopmental endophenotype in schizophrenia.

Minor physical anomalies (MPAs) and gamma oscillatory activity have been proposed as associated endophenotypes in schizophrenia. Combining these endophenotypes to create a composite endophenotype may help identify those at risk for schizophrenia better. The present study aims to investigate MPAs and gamma oscillatory activity in schizophrenia patients, their unaffected first degree relatives and healthy controls and appreciate whether they can be used together as a composite endophenotype.

Sporadic and familial subgroups of schizophrenia do not differ on dense array spontaneous gamma oscillatory activity

Genetic variations and developmental insults independently have been proposed to underlie aberrant gamma activity in schizophrenia. We investigated differences in spectral power in gamma (30-100Hz) frequency in patients with familial and sporadic schizophrenia. Subjects underwent resting-awake EEG recording on 192 channels. The two patient subgroups did not significantly differ in any of the gamma bands and regions. We conclude that complex gene-environment interactions are responsible for the limited power of familial-sporadic distinction in schizophrenia.

Aberrant gamma band cortical sources and functional connectivity in adolescents with psychogenic non-epileptic seizures: A preliminary report

Psychogenic non-epileptic seizures (PNES) resemble epileptic seizures, but lack clinically evident abnormal electrical activity in the brain. We aimed to assess resting gamma spectral power, current source distribution and functional connectivity in adolescents with PNES. Interictal, 32 channels electroencephalographic recording of 15 adolescents with PNES was compared with 10 matched healthy controls. Spectral power, current source distribution and lagged linear coherence were assessed. Statistically significant gamma spectral power, cortical sources and connectivity pattern was found in some brain areas. Region specific aberrant gamma activity and its relationship to psychopathology are discussed.

Fluvoxamine induced oculogyric dystonia and manic switch in a patient with obsessive compulsive disorder.

Fluvoxamine has a similar spectrum of adverse effects as compared to other selective serotonin reuptake inhibitors. However, fluvoxamine induced oculogyric dystonia is a rare instance in clinical practice. In this report, we present a case of obsessive compulsive disorder that developed oculogyric dystonia during the course of fluvoxamine mono-therapy and subsequently had a manic switch.