Do reflexes really slow down?

[wgeese]

I always question presuppositions, one of the major ones I hear a lot is "Your reflexes slow down as you get older".

Asking the internet oracle SEARCH ENGINE does not produce more than restatements of the presupposition in question. I'm lacking the hard data to prove GREATER AGE = SLOWER REFLEXES. But even if older people had less reflexes on average (which is true); this doesn't actually prove "greater age = slower reflexes", because we could be dealing with factors that are separate from age and more to do with culminations, common dysfunctions or even culture (Thus; age having nothing to do with reflexes).

Let's have at it! Who knows if Age really has a thing to do with reflexes?

Comments

ANSWERS

[kfharlock]

A 2004 study by Kido, Tanaka, and Stein in volume 82, issue 4 (pages 238-248) of the Canadian Journal of Physiology and Pharmacology titled "Spinal excitation and inhibition decrease as humans age" addresses this very issue.

Let me quote their own summary of their work:
"Although changes in the soleus H-reflex (an electrical analog of the tendon jerk) with age have been examined in a number of studies, some controversy remains. Also, the effect of age on inhibitory reflexes has received little attention. The purpose of this paper was to examine some excitatory and inhibitory reflexes systematically in healthy human subjects having a wide range of ages. We confirmed that both the maximum H-reflex (H_max) and the maximum M-wave (M_max) (from direct stimulation of motor axons) decrease gradually with age. The decrease in H_max was larger so the H_max/M_max ratio decreased dramatically with age. Interestingly, the modulation of the H-reflex during walking was essentially the same at all ages, suggesting that the pathways that modulate the H-reflex amplitude during walking are relatively well preserved during the aging process. We showed for the first time that the short-latency, reciprocal inhibitory pathways from the common peroneal nerve to soleus muscle and from the tibial nerve to the tibialis anterior muscle also decreased with age, when measured as a depression of ongoing voluntary activity. These results suggest that there may be a general decrease in excitability of spinal pathways with age. Thus, the use of age-matched controls is particularly important in assessing abnormalities resulting from disorders that occur primarily in the elderly."