Am J Psychiatry 1977; 134:775-781
Copyright © 1977 by American Psychiatric Association
Electrophysiological (H-reflex) studies of patients with tardive dyskinesia
JW Crayton, RC Smith, D Klass, S Chang and SE Ericksen
The authors studied the H-reflex recovery curves of 31 schizophrenic
patients with tardive dyskinesia in response to acute administrations of
apomorphine, amphetamine, or physostigmine and compared them with curves of
chronic schizophrenic patients without tardive dyskinesia and normal
volunteers. Their most unexpected finding was the absence of an H-reflex in
9 of the 31 patients with tardive dyskinesia. They also found a
relationship between severity of tardive dyskinesia and the value of the
facilitatory peak Hchi: patients with more severe tardive dyskinesia
symptoms had significantly higher values for Hchi.
