Association between attentional function and blink-suppressed pinch strength

We suggested that dual-task achievement, maximum muscle strength maintenance on pinch strength measurement combined with blink suppression for 5 seconds, is associated with attentional function and blink suppression. The subjects of our previous survey consisted of 27 young and 12 elderly persons. As attentional function reduces with aging, the necessity of a survey involving elderly persons was considered. As previously adopted, we used the Trail Making Test Japanese version (TMT): Part A and Part B for attentional function assessment. Since TMT Part B more accurately reflects cognitive function compared to TMT Part A, this survey was performed, hypothesizing that pinch endurance may reduce in subjects requiring a specific time for Part B. The subjects were 24 healthy elderly persons (74.7±8.1 years, 2 males, 22 females). Before pinch strength measurement, each subject was instructed to stop blinking for 5 seconds, and the number of blinks was counted. The pinch strength measurement time was established as 5 seconds, and changes in strength during that time were examined. On the first session of pinch strength measurement, no instruction was given (no suppression). Before the second session of measurement, each subject was instructed not to blink (under suppression). In a group with blinking under suppression, the maximum muscle strength on pinching was exhibited at 2 to 3 seconds in the absence of suppression (p=0.04), whereas it was exhibited at 3 to 4 seconds and at 4 to 5 seconds under suppression (p<0.046). In a group requiring a specific time for Part B, pinch strength persisted for 2 to 4 seconds, and significantly reduced (p≤0.04). Measurement of blink-suppressed pinch strength in healthy elderly subjects showed that a reduction in pinch strength at ≥3 seconds was associated with the time required for Part B. This measurement method was useful as a simple screening method.