Page 90 - Clinical variability in Noonan syndrome with emphasison ear and eye

CHAPTER 6
Sensorineural hearing impairment is a common feature in NSML, which appears in 15-20% of all cases (16,17). Hearing impairment is also associated with NS. Sharland et al. reported that the incidence of hearing impairment in 146 patients with NS by 1992 was 40%. In 3% of these cases, hearing impairment was sensorineural and in the remaining patients it concerned a conductive hearing impairment. A majority of the conductive hearing impairment is attributable to otitis media (4).
Recently, van Trier et al. described 34 patients with Noonan syndrome and hearing impairment. Nine patients had a sensorineural hearing impairment, two a permanent conductive hearing impairment, two other patients had a mixed hearing impairment and 20 patients had a conductive hearing impairment in the past caused by otitis media with effusion (18). The sensorineural hearing impairment varied between a mild high- frequency hearing impairment and a profound (uni- and bilateral) hearing impairment that was progressive in three patients (18).
Counseling and special care make it possible for a majority of the patients with NS and NSML to function normally in adulthood (6). Because hearing is very important for development, a cochlear implant (CI) plays a major role in the rehabilitation of patients with bilateral severe sensorineural hearing impairment. Limited information is known concerning the outcome of cochlear implantation in patients with NS and NSML. Therefore, the aim of the present study was to report the outcomes of five children with NS or NSML who were using a CI due to a severe to profound hearing loss.
Patients and methods
This case series describes four NS patients and one NSML patient, all with a mutation in PTPN1 and a severe to profound hearing loss, using a CI. The data for this study were gathered retrospectively. The clinical characteristics of all patients are described. The audiological data used concerned the outcome of the neonatal hearing screening (with Oto Acoustic Emissions) and the objective hearing threshold data obtained by Brainstem Evoked Response Audiometry (BERA) or Auditory Steady State Response (ASSR). Additionally, we used sound field audiometry (VRA; Visual Reinforcement Audiometry) and pure tone audiometry to evaluate the hearing loss pre- and post-cochlear implantation. Post-implantation speech perception was assessed using the child- friendly lists of the NVA test, a standardized Dutch monosyllable test (Dutch consonant- vowel-consonant [CVC] list, Bosman 1992). Speech perception score was expressed as the percentage of correct repeated phonemes. In all of the experiments, the speech was presented at a 65 dB Sound Pressure Level (SPL). The mean hearing loss, referred to as pure tone average (PTA), was the average hearing threshold at 1, 2 and 4 kHz as
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