Illusory Pulling Sensation in Older Adults is Associated With Cognitive Function Beyond Somatosensory Sensitivity

Illusory pulling sensations, induced by asymmetric vibrations applied to the fingertips, have attracted attention as a means to investigate sensorimotor processing and develop haptic interfaces. In addition, sensitivity to the illusory pulling sensation tended to decline in some older female participants, suggesting that factors related to aging and/or gender difference may be involved in this phenomenon. In this study, we aimed to clarify the contribution of somatosensory and cognitive functions to the illusory pulling sensation, focusing on aging and gender difference to examine these contributions. A total number of 60 older participants aged 63 to 80 years (30 males, 30 females) completed seven assessments, covering sensitivity to the illusory pulling sensation and a range of somatosensory and cognitive functions from vibration detection thresholds to general cognitive ability assessed by the Mini-Mental State Examination (MMSE). Consistent with prior findings, older females exhibited significantly lower sensitivity to the illusion. Interestingly, although gender differences were observed in some of the assessment items, such as hand length and performance on the parallel-setting task, none of these factors mediated the gender effect on the illusion. While age itself did not have a direct effect on the illusion, an indirect effect was observed through general cognitive function as assessed by the MMSE. These findings suggest that the illusory pulling sensation tends to weaken not only with aging, but also particularly when aging is accompanied by cognitive decline. Overall, gender and cognitive function may play key roles in individual differences in the illusory pulling sensation.