[Digitized analysis of hand movements in psychiatry. Methods, clinical findings and perspectives]

Numerous morbo- and pharmacogenic motor disorders are signs of psychiatric disease. In past, their exact and quantitative registration has not been possible or only possible using quite extensive procedures. Now we can use newer methods like the computer-aided analysis of hand movements, an elegant procedure allowing the detailed representation of discrete motor dysfunction. While these procedures are used with increasing tendency in neurology, their use aiming the investigation of psychiatric hypotheses is still at the beginning. Relevant application fields of the computer-aided analysis of hand movement are the differentiated and quantitative registration of movement disorders that could only be detected by use of rating scales so far; the registration of subclinical motor abnormalities leading to the detection of the participation of the motor system in certain subgroups of psychiatric patients; the differentiation of morbo- and pharmacogenic motor disorders (e.g. hypokinesia induced by neuroleptics versus schizophrenic negative symptomatology); the registration of neurological soft signs (e.g. in schizophrenic patients); the individual dose adjustment accounting for the threshold of extrapyramidal motor side effects (EPMS) under neuroleptic treatment and the detection and documentation of clinical and subclinical tremor. For some of these application fields there already exist promising findings. Some newer results will be presented. Schizophrenic patients were found to manifest impairments of velocity and degree of automatization and a reduced regularity of repetitive hand movements (fine motor dysdiadochokinesia)--a possible indicator for a disturbance of cerebral development. Patients with Alzheimer's disease showed loss of automatization and well preserved peak velocity. This finding could be relevant for the early detection of Alzheimer's dementia. Distal EPMS induced by neuroleptics can be exactly documented and their course can be represented using this method. The quick and economical utilization of digitized analysis of hand movements makes this procedure suitable for a broader application in the ambulatory setting.