The Effect of Ageing Upon Physiological Tremor

It is a matter of common observation that the standard of motor performance declines with advancing years. There are several factors which may be associated with this. The conduction velocity in human peripheral motor nerve fibres has been shown to decrease by about 15 % between the third and ninth decades (Wagman and Lesse, 1952; Norris, Stock, and Wagman, 1953). On the sensory side, the perception of vibration applied to the lower limbs is impaired in an increasing pro-portion of apparently normal people after the age of 50 years (Pearson, 1928; Cosh, 1953), and ischaemic and post-ischaemic paraesthesiae are likewise experienced less constantly (Poole, 1956). Reflex activity is also impaired more than can be