Where hearing difficulties exist despite a normal hearing test, consider the presence of an underlying subclinical disorder or a developing problem.
CASE HISTORIES Case 1A 50-year-old woman presented with a 3-month history of hearing difficulty in her left ear. This was related to a sudden feeling of blockage in her left ear with perceived distortion. The sensation of blockage cleared initially, but then recurred and persisted. Audiometrically her hearing was normal. An initial diagnosis of King-Kopetzky syndrome was made and further hearing tests were organized. Her transient-evoked otoacoustic emissions were poor. As the perception of sound can be affected by both peripheral and central auditory processing disorders, central speech tests were performed and found to be normal. Her hearing difficulty persisted, as did the sensation of blockage in her left ear. It was felt her symptoms were now suggestive of endolymphatic hydrops or a variant of Menière's disorder rather than King-Kopetzky syndrome. Her symptoms initially improved with diuretic use. A low salt diet had not been helpful. Nineteen months after her initial presentation her hearing had deteriorated. She now had a low frequency sensorineural loss ( Figure 1) but with good speech recognition. A magnetic resonance imaging scan of her internal auditory meati and brain was normal. This evolving picture supported the diagnosis of Menière's disorder.
Case 2A woman aged 53 reported a hearing loss in her left ear after an upper respiratory tract infection, although she had initially felt it recovered completely. She had no noted tinnitus or dizziness, nor any neurological problem. Audioscan audiometry and distortion product otoacoustic emissions were normal. She reattended 4 years later complaining of progressive hearing loss, tinnitus, numbness of the left side of her face and a mild disturbance of balance over the preceding year. She was noted to have reduced facial sensation in the area supplied by the mandibular branch of the left trigeminal nerve and a reduced left corneal reflex. Pure tone audiometry (Figure 2) showed a marked deterioration in her hearing thresholds. Magnetic resonance imaging (Figure 3) demonstrated a partly cystic, partly solid extra axial mass extending into a widened left internal auditory meatus and displacing the fifth cranial nerve at its root entry zone. Radiologically this was consistent with a large vestibular Schwannoma. Peroperatively this mass was found to be a facial neuroma. Postoperatively she had a persisting profound left hearing loss, a seventh lower motor nerve palsy and ataxia.
Case 3A 23-year-old medical student on an ENT attachment reported having been aware of hearing difficulties since sheA u g u s t 2 0 0 6Welsh Hearing Institute, University Hospital of Wales, Cardiff CF14 4XW, UK