Abstract
A previous study of normal subjects has well established the fact that in the case of the knee-jerk the average length of time elapsing between the instant of stimulation of the patellar tendon and the appearance of action currents in the executant muscle is .0197 seconds. 1 This average is based upon records obtained from 87 individuals who presented reflex times ranging from .0114 to .0268 seconds. Reflex conduction rate is relatively constant for the same individual under normal conditions. However it was thought that certain mental and physical abnormalities might affect it and with this thought in mind a study was made of a case diagnosed as toxicinfective-exhaustive psychosis. When the first records were obtained the patient displayed catalepsy, cerea flexibilitas, muteness, stupor, and absolute disorientation. The findings revealed her reflex time to be .0059 seconds. Four days after these records were obtained she showed marked improvement—the catalepsy and cerea flexibilitas had practically disappeared, and she was talking and enjoying herself with other patients. Records now revealed the fact that her reflex time was .0180 seconds. Twenty-five days later when she was discharged as “physically improved and mentally recovered” her reflex time was .0185 seconds. Thus it appears that the catatonia here was accompanied by a markedly reduced patellar tendon reflex time, and that as the catatonic condition cleared up the reflex time approached the average for normal individuals. An explanation of this increase in reflex conduction rate during catalepsy is difficult to make. It may be due to increased facilitation of transmission of the nerve impulse, to blocking out of parts of the arc ordinarily traversed by the nerve impulse, or to more obscure and involved alterations of neural, neuromuscular, or muscular factors.
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