Diagnostic specificity and neuroanatomical validity of neurological abnormalities in first-episode psychoses.

OBJECTIVE: Neurological abnormalities are frequently seen in patients with first-episode psychotic disorders but are generally considered to be diagnostically nonspecific, neurologically nonlocalizing, and, hence, "soft." This study examined the neuroanatomical correlates and diagnostic specificity of abnormal findings on the neurological examination in first-episode schizophrenia and other psychotic disorders.
METHOD: Neuroleptic-naive patients with schizophrenia (N=90) and with nonschizophrenia psychoses (N=39) and carefully matched healthy subjects (N=93) were compared on total and factor scores for a reliable subset of Neurological Evaluation Scale items. The relationship between neurological examination abnormalities and alterations in the relevant brain structures as assessed by magnetic resonance imaging was examined in a subset of subjects.
RESULTS: Factor scores for repetitive motor task abnormalities were higher in both patient groups, relative to the healthy group, and did not distinguish between the patient groups. Factor scores for abnormalities in cognitively demanding and perceptual tasks were markedly higher in the schizophrenia group, relative to both comparison groups, and were not different between the nonschizophrenia psychoses group and the healthy comparison group. Higher scores for the cognitive/perceptual abnormalities factor were correlated with smaller volumes of the left heteromodal association cortex.
CONCLUSIONS: Neurological signs may serve as expedient bedside measures that are potentially useful in the assessment of idiopathic psychoses, and cognitive/perceptual neurological signs may have a measure of diagnostic specificity. These findings provide neurobiological validation of abnormal findings on the neurological examination. These abnormalities may reflect discrete neuroanatomical alterations in schizophrenia and may have a localizing value.