Decline of tactile acuity in aging: a study of body site, blood flow, and lifetime habits of smoking and physical activity

Abstract

Tactile acuity of 60 older subjects (> or = 65 years) and 19 younger subjects (18-28 years) was assessed by two-point gap thresholds at the upper and lower surfaces of the forefinger, at the upper and lower surfaces of the feet, and at the volar surface of the forearm. The older subjects were assigned to one of four groups of 15 subjects each, depending on reported lifetime habits of physical activity and smoking: (1) active smokers, (2) active nonsmokers, (3) inactive smokers, and (4) inactive nonsmokers. Peripheral blood flow was assessed at the forefinger, foot, and forearm by means of laser-Doppler imaging and skin temperature recordings, under resting conditions and during and after a 5-min exposure to mild cooling (28 degrees C). Consistent with previous studies, tactile acuity thresholds in the foot and finger averaged about 80% higher in the older subjects than in the younger subjects, but only about 22% higher in the forearm. Although the upper surface of the fingertip was more sensitive than the lower surface in both younger and older subjects, the age-related decline in tactile acuity was nearly identical on both sides of the finger and foot. The latter finding refutes the hypothesis that the larger effect of aging in the extremities results from greater physical wear and tear on the contact surfaces of the hands and feet. Self-reported lifetime histories of physical activity and smoking were not significantly associated with measures of cutaneous blood flow or tactile thresholds. Possible reasons for this lack of association are discussed, including the inherent limitations of testing only healthy older subjects, and the concept of "successful aging".

Sex differences in age-related changes on peripheral warm and cold innocuous thermal sensitivity

“…Furthermore, research has shown that the sensitivity of the skin to such stimuli declines with ageing [7,8,9,10,11]. From the present study there is clear evidence that thermal sensitivity declines with ageing to both a cold Whilst the present study supports previous research, it also adds to our current knowledge about the decline in thermal sensitivity with ageing and how it differs between the two sexes.…”

“…Impaired cutaneous vascular function and delays in the sweating and shivering thresholds have been reported in age comparison studies [2,3,4,5,6]. Likewise, reduced thermal sensations in older adults have been reported, alongside a number of other tactile responses (touch, pressure and noxious thermal sensitivity) [7,8,9,10,11]. With an increasing ageing population and increased reports of climate change, understanding the age related changes in our ability to thermoregulate is vitally important.…”

Tactile acuity in experienced Tai Chi practitioners: evidence for use dependent plasticity as an effect of sensory-attentional training

“…The failure to find an association between exercise and tactile acuity is inconsistent with the blood flow hypothesis which theorizes that TC enhances tactile acuity in a non-specific manner by increasing peripheral blood flow; this null result is in accord with a large study by Stevens et al (2003) which found both cumulative exercise and current hours-per-week to be unrelated to tactile spatial acuity.…”

“…In this case, tactile acuity should be associated with cumulative lifetime and/or current intensity of exercise in both the TC group and the control group since exercise is a potent modulator of peripheral blood flow (although a null correlation between exercise and tactile acuity has been previously reported (Stevens, Alvarez-Reeves, Mack, & Green, 2003).…”

Age-related changes in cutaneous sensation in the healthy human hand

“…The greater morphological changes and reduced numbers of Meissner's corpuscles seen in the hands of older manual workers and to a lesser extent, older males in general (Cauna 1956(Cauna , 1965, suggest that increased damage may occur to neuromuscular structures in high contact areas (Cauna 1965). Previous studies found no difference between sensory declines on the dorsal and ventral sides of the finger (Stevens et al 2003) and foot (Mitchell and Mitchell 2000) with age, and suggested increases in skin thickness (Mitchell and Mitchell 2000) and skin wear (Stevens et al 2003) did not contribute to sensory decline. However, in these studies, the skin of the palm was not investigated.…”