Pain expression and stimulus localisation in individuals with Downʹs syndrome

Background Individuals with Downʹs syndrome do not always exhibit signs of distress in reaction to noxious stimuli comparable with the general population. This pilot study was designed to measure the ability of individuals with Downʹs syndrome to detect and express sensation in comparison with healthy volunteers. Methods In the first test, the latency of pain detection to self-administered cold stimuli on the wrist and on the temple was measured. The second test was designed to assess ability to localise cold stimuli on sites on the hand, on the face, and in the mouth. Findings 75 control individuals and 26 individuals with Downʹs syndrome were tested. Individuals with Downʹs syndrome had significantly longer median latencies than controls: Downʹs syndrome median (quartiles) 28·7 s (1st 18·0, 3rd 47·6); controls 20·6 s (1st 12·4, 3rd 31·0); p=0·0005. In addition, more individuals with Downʹs syndrome had difficulties in localising the cold stimulus. The differences in distribution for precise localisation were significant for the hand (Downʹs syndrome [p<0·0005] 54%; control 99%), the mouth (31%; 84%), and the face (54%; 97%). Interpretation Individuals with Downʹs syndrome are not insensitive to pain. However, they do express pain or discomfort more slowly and less precisely than the general population. This implies that medical teams managing these patients should use pain-control procedures, even in the absence of obvious pain manifestations.