Increased Single-Fiber Jitter Level Is Associated With Reduction in Motor Function With Aging.
Tae Chung, Yanli Tian, Jeremy Walston and 1 others
PMID 29498943WHAT IT FOUND
In mice, timing variability in nerve-to-muscle signals was linked to weaker grip and poorer standing.
Overall nerve-muscle electrical response did not track strength. This is animal data, not a human finding.
Key findings
01Old mice had significantly lower forelimb and all-limb grip strength than young mice.
02Higher single-fiber EMG jitter was inversely correlated with grip strength and standing activity, while CMAP did not correlate with these measures.
03When age was included in the analysis, jitter no longer predicted grip strength.
STILL TO COME
How it was doneWhat they found
Read the rest of this summary
You get three full summaries a month, free, and we do not ask for a card. Search, the TL;DRs and your library stay unlimited either way.
What it does not show
The study used mice, so it cannot tell how this applies to human patients. Only 6 young and 9 old mice were studied, which limits confidence. The researchers compared only two age groups, not a range of ages. The findings are associations, not proof that jitter causes weakness. After age was included, jitter did not predict grip strength independently. The study did not measure motor unit number or test an intervention.
Declared interests
No author conflict-of-interest declaration is included in the supplied text. The publication types indicate NIH extramural research support.
The easy way to misread this
Do not conclude that this identifies a cause of human age-related weakness. The study was in mice, showed correlations, and jitter did not predict grip strength after age was included.