Ball experiments in 32 acute akinetic catatonic patients: deficits of internal initiation and generation of movements.

We undertook ball experiments in 32 akinetic catatonic patients in order to determine specific functional deficits in the motor system in akinetic catatonia. Standardized ball experiments (catching, throwing, stopping, kicking) were conducted in 32 acute akinetic catatonic patients (23 without neuroleptics on admission), diagnosed according to Lohr, Rosebush, and the Diagnostic and Statistical Manual of Mental Disorders (3rd ed, revised) on days 0 and 21. Additionally, associated psychopathology was evaluated using different scales on days 0 and 21: the Global Assessment Scale, the Brief Psychiatric Rating Scale, the Hamilton-Anxiety Scale, the scale for the assessment of negative symptoms (SANS), and the Simpson scale for extrapyramidal side effects (SEPS). Significantly more patients were able to perform more externally guided tasks (catching, stopping) than internally guided tasks (throwing, kicking). Patients showed significantly more posturing and awkward movements on day 0 than on day 21. There was a significantly positive correlation between hypokinetic extrapyramidal features (SEPS) and negative symptoms with their cognitive alterations (SANS) on day 0. The findings suggest a deficit of internal initiation, as in parkinsonism, as well as a dysfunction in the generation of voluntary movements in akinetic catatonia. We assume an underactivity in the dorsolateral prefrontal cortex and the supplementary motor area with consecutive down-regulation of the cortical-striatal-thalamic circuit, the "motor loop," in catatonia.