Psychomotor speed in chronic low-back pain patients and healthy controls: Construct validity and clinical significance of the measure

The effect of ethanol on reaction times was studied in 5 healthy men to tes t the construct validity of the measure. Reaction times were studied among 61 healthy controls and 99 patients with chronic low-back pain (68 moderate and 31 severe) to evaluate the diagnostic value of reaction time measureme nts. Analysis of receiver operating characteristics was used to calculate t he discriminative pou er of the reaction time measurements. The severity of low-back pain was associated with slow reaction times but the diagnostic v alue of a single reaction time measurement was low due to insufficient sens itivity. In conclusion, even though many patients with low-back pain suffer from central impairment of motor function, a single reaction time measurem ent is not usable in evaluation of the severity of low-back pain.