foundation · clinical case

Mild unsteadiness, age 72

Vignette

A 72-year-old woman has mild unsteadiness without falls. She has no acute vertigo. SHA shows gain of 0.18 at 0.01 Hz (below the normal band of 0.25–0.55 at that frequency) but normal gain from 0.04–0.64 Hz, with normal Tc and symmetric responses.

RCT pattern

Gain · eye / chair00.601.200.010.020.040.080.160.320.64frequency (Hz, log)Phase lead · degrees-2030800.010.020.040.080.160.320.64frequency (Hz, log)Symmetry · %-500500.010.020.040.080.160.320.64frequency (Hz, log)
Three-panel SHA summary. Shaded green = published normal band. Solid marker = patient/archetype curve; dashed = overlaid reference if shown.

Question

What does this pattern most likely represent?