Condition · Neural

Bell's Palsy — Serial Monitoring

Tracking facial nerve recovery — the reflex returns as the nerve recovers

The reflex as a recovery marker

In Bell's palsy with a lesion proximal to the stapedial branch, the reflex is absent on the affected probe side during the acute phase. Serial testing during recovery shows the reflex returning — often before, or in step with, the return of visible facial movement — making it a useful objective marker of recovery.

Reading the time course

The key is the trend across repeated tests: a probe-ear column that is absent acutely and then refills is the signature of recovering stapedial-branch function.

The reflex signature

Stim. Right
Stim. Left
Probe Right
Absent
Absent
Probe Left
Present
95 dB HL
Present
90 dB HL
The characteristic four-cell grid for this condition.

An efferent-limb probe-ear pattern acutely; serial testing shows the affected column refilling during recovery.

Reflex decay

0s2s4s6s8s10s0%50%100%50% criterion
Negative (normal) decay — amplitude is well maintained across the 10-second hold. Once a reflex can again be recorded on the recovering side, decay can be assessed; during the absent phase it cannot.

Pure-tone audiogram

0204060801002505001k2k4k8kFrequency (Hz)Hearing level (dB HL)
○ Right ear✕ Left ear
Hearing is typically normal — the auditory pathway is unaffected.

Frequencies plotted: 250, 500, 1k, 2k, 4k, 8k Hz.

References for this page

  1. Mangham CA, Carberry PH, Brackmann DE (1980). Management of intratemporal vascular tumors and the acoustic reflex in facial nerve disorders. Laryngoscope, 90(11), 1813–1819.
  2. Hall JW (2014). Introduction to Audiology Today. Pearson, Boston.
  3. Katz J (Ed.) (2015). Handbook of Clinical Audiology (7th ed.). Wolters Kluwer, Philadelphia.
Want to contrast this with another condition? The comparison tool places any two reflex signatures side by side.