Theory 14/Geriatrics & Frailty

Falls Are a Signal-to-Reserve Problem

The claim

Falls are set by the ratio of sensory noise to postural reserve rather than by either alone, so interventions that reduce noise and interventions that build reserve should have additive effects.

01The mechanism

Balance requires estimating body position from noisy signals and correcting with available strength and reaction time. Error grows with noise and shrinks with reserve.

Falls occur when the combination exceeds the margin, which is why single-factor interventions have modest effects.

02What this is not

Strength-only or vision-only models

Those target one term. This targets the ratio, which predicts additive benefit from both.

03Predictions

P1Fall rate should track the ratio.
P2Combined interventions should outperform either alone.

04Refutation

Fall rate tracking one term at controlled other would favour single-factor models.