Long-term adaptation to neck/shoulder pain and perceptual performance in a hand laterality motor imagery test

The effect of neck/shoulder pain on the performance in a hand laterality motor imagery test was studied. Responses to the Cooper and Shepard (1975, Journal of Experimental Psychology: Human Perception and Performance 104 48-56) hand laterality test were explored in twenty-four individuals with chronic non-specific neck pain and twenty-one subjects with chronic neck pain of traumatic origin (whiplash-associated disorder). Twenty-two controls were also included in the study. Digitalised right- or left-hand stimuli were presented at five different stimulus angles (0 degrees, 45 degrees laterally, 90 degrees laterally, 135 degrees laterally, and 180 degrees). The experimental task was to decide the laterality as fast and accurately as possible. The performance, both reaction time (RT) and accuracy, of the two experimental groups was contrasted with that of the control group. The main results revealed that the subjects afflicted with whiplash injury on the average exhibited a faster response pattern than symptom-free healthy controls. Despite their musculoskeletal deficits and experience of pain these volunteers also exhibited a preserved speed-accuracy tradeoff. Longer duration of time with symptoms of neck pain was, moreover, associated with progressively faster RTs. These results point to perceptual learning and may reflect different stages of adaptation to neck pain.