Auditory and optic neuropathy in Kjer ’ s disease: case report S C HAAKSMA-SCHAAFSMA, P VAN DIJK, F G DIKKERS Department of Otorhinolaryngology/Head and Neck Surgery, University Medical Center Groningen, University of Groningen, The Netherlands Abstract Objective: Description of a female patient with diagnosed Kjer’s disease and sensorineural hearing loss, who specifically complained of a progressive inability to understand speech in noisy situations. Design: Case report. Subject: A 30-year-old, Caucasian woman with Kjer’s disease. Results: Audiological assessment showed low-frequency sensorineural hearing loss and a disproportionate deterioration in speech discrimination. This inconsistency gave rise to suspicion of possible aggravation. Follow-up testing showed that brainstem responses were absent, while clear otoacoustic emissions and cochlear microphonics were present. Hearing aids were fitted but no improvement was shown. Conclusion: This case shows a combination of auditory neuropathy and Kjer’s optic neuropathy. It also illustrates that the combination of unexplained hearing loss and apparently inconsistent audiometric outcomes may be associated with auditory neuropathy. Such unexpected hearing evaluation outcomes may be due to other neurological conditions, such as Kjer’s disease. Key words: Optic Atrophy; Auditory Neuropathy; Auditory Brainstem Response; Sensorineural Hearing Loss; Otoacoustic Emissions; Cochlear Microphonic Potentials Introduction Kjer’s disease is a hereditary autosomal dominant condition causing optic atrophy. It was first described by Batten in 1896, and named Kjer’s optic neuropathy in 1959. 1,2 It involves slowly progressive, bilateral atrophy of the optic nerves, which is characterised by loss of visual acuity, scoto- mas, optic disc pallor and abnormalities of colour vision. 1,3,4 Autosomal dominant optic atrophy is the most common form of hereditary optic neuropathy. 5 The majority of cases are associated with mutations in the OPA1 gene. 6,7 A prevalence of between 1: 10 000 in Denmark and 1: 50 000 elsewhere has been reported. 5,8 In some cases of autosomal dominant optic atrophy, the optic pathology is accompanied by other clinical findings, such as hearing impairment, which can range from subclini- cal to severe and congenital. 4,9 –12 Other neurological and neuromuscular symptoms have also been described, such as ataxia and sensory-motor polyneuropathy. 13,14 Pure tone audiometry may show high- or low-frequency sensorineural hearing loss. Auditory brainstem responses may be absent or severely desynchronised; however, otoacoustic emissions may be completely normal. 12,13,15 These clinical and investigative data agree with the diag- nostic criteria for auditory neuropathy spectrum disorder. 16 This condition encompasses a range of disorders which affect auditory neural function but spare cochlear outer hair cell function. 17,18 Auditory neuropathy spectrum disorder may occur in the absence of any apparent medical problem, or in combination with a variety of other symptoms such as anoxia, hyperbilirubinaemia, infectious processes and immune disorders. 19 The condition can be associated with several genetic diseases and syndromes, including Freidrich’s ataxia, Charcot –Marie –Tooth syndrome, mito- chondrial disorders and optic nerve atrophy. 9,19 In cases with auditory neuropathy, the neural response has a diminished ability to follow fast temporal changes in the stimulus. The primary lesion is presumably located in the inner hair cells, in the synapses between hair cells and the auditory nerve, or in the auditory nerve fibres them- selves. 20 This lesion affects the normal synchronous activity in the auditory nerve, which explains the absence of a normal brainstem response. Patients with auditory neuropathy spec- trum disorder complain of poor speech recognition. This is a result of impairment in temporal processing. 21 Case report A 30-year-old, Caucasian woman presented to the otorhino- laryngology department of our tertiary referral hospital for evaluation. She had already been diagnosed with Kjer’s disease one year previously. She complained of hearing dif- ficulties especially in noisy situations. Her family history included at least four generations suffering from optic atrophy combined with hearing loss. The patient had no Accepted for publication 18 May 2011 First published online 6 October 2011 The Journal of Laryngology & Otology (2012), 126, 309–312. CLINICAL RECORD © JLO (1984) Limited, 2011 doi:10.1017/S0022215111002696