Foundation

A 6-year-old reviewed after grommet insertion

A 6-year-old who had ventilation tubes (grommets) placed two months ago is brought for routine review. The parents report hearing has improved. Otoscopy shows a tube in place and appearing patent.

Investigations

Audiogram

0204060801001202505001k2k4k8kFrequency (Hz)Hearing level (dB HL)[[[[[[○ air conduction[ bone conduction

Tympanogram

-400-300-200-10001002000.00.51.01.52.02.53.0Ear-canal pressure (daPa)Admittance (mmho)

Flat tympanogram with an abnormally LARGE equivalent ear-canal volume. Near-normal hearing on the audiogram.

What does the flat trace with a large ECV indicate here?