Developmental and sex differences of somatosensory perception

Introduction: There are controversial discussions and contradictory results regarding age and sex related differences of somatosensory perception. With Quantitative Sensory Testing (QST) it is possible to quantify almost all somatosensory modalities (detection and pain from thermal and mechanical stimuli). A prior study suggests age and sex related differences when comparing younger (6–8 years) with older children (9–12 years) and with adolescents (13–16 years) respectively (Blankenburg et al., 2010).

The aim of our current study is to assess the impact of age and sex using the QST protocol of the German research network on neuropathic pain (DFNS).

Patients and methods: The QST protocol of the DFNS was used in 88 healthy 7 year old children (44 girls and 44 boys) and 88 healthy 14 year old adolescents (44 girls and 44 boys). The sample size was calculated from a power analysis of the previous study (Blankenburg et al., 2010).

Results: Children were less sensitive to thermal detection stimuli than adolescents (cold T=3.34, p=0.001; warm T=2.35; p=0.02). No differences were observed for tactile and vibration detection, since all measured thresholds were close to the lower or upper end of test stimuli (bottom effect). Children were more sensitive than adolescents to almost all pain stimuli (heat pain T=3.10, p=0.002; pressure pain T=9.48, p≤0.001; mechanical pain threshold T=2.58, p=0.01, mechanical pain sensitivity T=5.43, p<0.001). Girls were more sensitive than boys to warm detection stimuli (T=2.63, p=0.009) and heat pain stimuli (T=2.08, p=0.04). No sex differences were found regarding other stimuli.

Conclusions: Results indicate significant age differences of somatosensory perception in terms of increased thermal detection and decreased pain sensitivity in adolescents compared to children. In contrast, sex differences can be neglected. The underlying mechanisms of the observed differences are still unknown. Influencing factors may be psychological (attention, anxiety and coping strategies) and biological (functional maturation of interneurons in the cortex and the dorsal horn of the spinal cord; Fitzgerald at al., 2005). Further clinical studies are required to determine factors related to the age effects in children.