Neuroanatomical correlates of neurological soft signs in antipsychotic-naive schizophrenia

Ganesan Venkatasubramanian, Peruvumba N. Jayakumar, Bangalore. N. Gangadhar and Matcheri S. Keshavan

(all except Keshavan are at NIMHANS, Bangalore. Dr. M Keshavan who is one of the main pillars of schizophrenia research is at Detroit, USA)

This is a first of its kind paper to have analysed Soft Neurological Signs in drug-naive schizophrenics to a greater detail (barring Keshavans' earlier work on cerebellum and Bottmer et al). However many years of research has indeed told us about changes in prefrontal cortex volumes, superior temporal gyrus volume etc to be different in schizos, this study establishes a correlation of them to clinical features especially motor sequece signs, hence ascertaining neuroarchitectal basis of observed motor behaviour and also implicating neurocircuitry involvment at large. This paper pushes schizophrenia as to a neurodevelopmental disorder and not a neurodegenerative disorder. Look into Keshavan's papers for more details.

Abstract

Recent imaging studies suggest that the so-called “soft” neurological signs in schizophrenia might have neuroanatomical validity. We examined gray matter volume correlates of neurological soft signs (NSS) in antipsychotic-naive schizophrenia patients using an automated image analysis technique. NSS were assessed using a modified neurological evaluation scale with good inter-rater reliability. Magnetic resonance images of 30 schizophrenia patients and 27 age-, sex-, education- and handedness-matched healthy controls were processed using optimized voxel-based morphometry (VBM). Logistic regression analysis showed that only the Motor Sequencing Signs (MSS) sub-score was a significant predictor of subject's status among the NSS sub-scores. Optimized VBM analysis showed that the MSS sub-score had a significant negative correlation with total and regional gray matter volumes (prefrontal, posterior cingulate, temporal cortices, putamen, and cerebellum) in schizophrenia patients but not in controls. Prefrontal and temporal cortices, putamen and cerebellum had significant volume deficits in patients. Cortical and cerebellar correlates of the sub-score MSS support the concept of “cognitive dysmetria” in schizophrenia.

Psychiatry Research: Neuroimaging
Article in Press, Corrected Proof
doi:10.1016/j.pscychresns.2007.12.021