Maintenance of induced muscle tension, stimulus generalization performance, and schizophrenia

Abstract

Hand‐dynamometer induced muscle tension was manipulated in the context of an experimental paradigm that included tests of discrimination and generalization with rigorously defined schizophrenic and affective patients, as well as schizotypic and normal controls (total N = 44). The experiment was designed to test predictions that derive from Broen and Storms' (1967) learning/motivational analysis of schizophrenic performance deficits. The results failed to support the theoretical predictions, but did reveal that the ability to maintain induced muscle tension within prescribed limits discriminated reliably between the groups (p ⩽.03) and that this discriminability increased with increasing tension demands (p ⩽.001). The data are discussed in terms of possible relations to basic sensory/motor (i.e., neuromuscular and/or proprioceptive) mechanisms as well as to more central psychological (i.e., attentional/cognitive) mechanisms, and directions for future research are outlined.

Maintenance of grip-induced muscle tension: A behavioral marker of schizophrenia.

“…The results of our investigations replicate and extend the findings of Johnson et al (1986). The ability to maintain prescribed levels of tension on a hand dynamometer differentiated schizophrenic patients from normal control subjects and from nonschizophrenic psychiatric patients.…”

“…The following modifications of the basic procedure were made: (a) the visual discrimination component was eliminated; (b) in addition to the standard tone of 1315 Hz, 64 dB (the original tone in Johnson et al's, 1986, study was set at 83 dB), a lower volume tone (1315 Hz, 48 dB) and a no-tone condition were included; (c) the information provided by the feedback tone was used as a between-subjects variable, so that in different formats the tone was used to indicate either performance errors (off target) or correct performance (on target).…”

“…This promise has been limited, however, by the absence of sensitive, reliable laboratory measures of motor dysfunction. Recent research by Johnson, Rosen, and Davis (1986), although aimed at an examination of a different issue, discovered that maintenance of gripinduced muscle tension may provide such a measure. In Johnson et al's study, schizophrenic patients performed significantly worse than both affective patients and normal controls when asked to maintain precise levels of tension on a hand dynamometer.…”