Sensory Temporal Thresholds and Interhemispheric Transfer Times in Multiple Sclerosis: A Preliminary Study of a New Outcome Measure

Abstract

This preliminary study investigated the potential of a cerebral lateralization technique that measures both, temporal judgements to sensory stimuli and interhemispheric transfer time (IHTT), as an outcome measure in multiple sclerosis (MS). Tactile stimulation was delivered to one or both hands by mechanical tactile stimulators. Pairs of light emitting diodes were presented to hemifields for visual stimulation. Response consisted of a binary forced-choice (YES/NO) judgement as to the simultaneity of the onset of pairs of stimuli. Both tactile and visual temporal thresholds were significantly higher in MS patients than controls in every presentation condition. IHTT estimates (threshold differences between unilateral and bilateral presentations) for the tactile and visual tasks were also significantly longer in patients than controls. Age correlated with sensory temporal thresholds for the control group only. These findings suggest that this technique may be a useful outcome measure in MS. We hypothesize that myelin injury slows central conduction therefore impairing the ability to judge the onset of sensory stimuli and increasing IHTTs.