PRECISION OF MEASURES OF SACCADIC EYE-MOVEMENTS AND CONVENTIONAL PSYCHOMOTOR FUNCTION-TESTS

Measures of variability are rarely quoted in drug studies of psychomot or function. Five recent studies were therefore analysed to calculate the coefficients of variation for different tests of psychomotor funct ion, both during and between study days. Saccadic eye movement analysi s and critical flicker fusion threshold were found to have low coeffic ients of variation (ranging from 2.7 to7.5 per cent) while visual anal ogue rating scales and the digit symbol substitution test were found t o have much higher coefficients of variation (ranging from 7.9 to 17.6 per cent). It is suggested that measures of test variability be routi nely assessed in psychomotor studies as a check on test methodology.