Contralateral influences on patellar tendon reflexes in young and old adults.
In an effort to more fully investigate age-related changes in spinal reflex parameters, we measured force-time characteristics of the patellar tendon reflex in aged subjects and contrasted these with data obtained from college-age individuals. We also conditioned the tendon jerk with a tap to the contralateral tendon. The results showed a marked tendon reflex enhancement in the old group, consisting of greater overall reflex force produced by the quadriceps. In both groups, the contralateral conditioning stimulus produced a short-latency inhibition (at 25 msec) followed by a longer-latency facilitation (beginning at 75 msec). Both the early inhibition and the later reflex enhancement were greater in the aged subjects. We suggest that some age-related change may occur at the spinal level to compensate for decrements in more complex motor functioning.
Kamen
G
G
Department of Physical Therapy, Boston University, MA 02215.
Koceja
D M
DM
D000125:Achilles Tendon / Q000502:physiology; D000293:Adolescent; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology*; D007839:Functional Laterality; D006801:Humans; D012026:Reflex, Stretch; D013997:Time Factors