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Changes in cutaneomuscular reflex responses in relation to normal ageing in man
Martine A Nadler1, Linda M Harrison, John A Stephens
1Department of Physiology, Gower St., University College London, London WC1E 6BT, UK.
Experimental Brain Research
|August 23, 2002
Summary
Elderly adults show reduced spinal reflex responses (CMRs) in hand muscles during finger movements compared to younger individuals. Transcortical reflex components were less affected by aging.
Area of Science:
- Neuroscience
- Gerontology
- Human Physiology
Background:
- Cutaneomuscular reflex responses (CMRs) are crucial for motor control.
- Understanding age-related changes in neuromuscular function is vital for maintaining mobility and preventing falls in older adults.
Purpose of the Study:
- To investigate age-related differences in cutaneomuscular reflex responses (CMRs) in the first dorsal interosseous (1DI) hand muscles.
- To compare spinal and transcortical reflex components between elderly and young adults during specific hand tasks.
Main Methods:
- Surface electromyography (EMG) was used to record muscle activity from the 1DI muscles of 23 elderly and 11 young adults.
- Participants performed index finger abduction and a grip task while digital nerves of the index finger were stimulated.
- Analysis focused on spinally-mediated (E1) and transcortical (I1, E2) components of the CMRs.
Main Results:
- The spinally-mediated E1 component of CMRs was significantly smaller in elderly subjects compared to young subjects for both tasks.
- Transcortical components (I1 and E2) did not show significant age-related changes in size.
- The incidence of the I1 transcortical component was significantly reduced in the elderly group.
Conclusions:
- Normal aging is associated with diminished spinal reflex excitability in hand muscles.
- Age-related changes in transcortical reflex pathways may differ from spinal pathways, with reduced participation rather than altered magnitude.