ARM TREMOR, TARDIVE-DYSKINESIA, AND MENTAL-RETARDATION

The arm tremor of adults diagnosed as having mental retardation and/or tardive dyskinesia was examine through an analysis of the acceleratio n properties of several arm postures. The degree of arm acceleration w as increased in all groups compared to a control group without mental retardation. The tardive dyskinesia and/or mentally retarded groups al so showed a shift to a lower modal frequency of physiological tremor. Results showed that both time domain and frequency properties of the t remor acceleration signal are necessary to distinguish between groups. The neuroleptic medication appears to engender a dual and opposing in fluence on performance in the arm tremor task for the mentally retarde d group, The medication reduces behavioral variability as indexed by a nalyses Of arm acceleration over time (tin domain) but lowers the moda l frequency of physiological tremor.