Fine force instability: a quantitative measure of neuroleptic-induced dyskinesia in the hand

The results of a new procedure for the quantification of tardive dyskinesia (TD) in the hand are reported. Fourier analyses were made of steady-state isometric force control in 41 neuroleptic-treated patients with and without hand TD. Results indicated that spectral analysis of isometric posture represents a reliable, sensitive, and valid measure of neuroleptic-induced dyskinesia.