Study of the peripheral and central auditory pathways in patients with mucopolysaccharidosis

Objective: To investigate the peripheral and central auditory pathways in mucopolysaccharidosis (MPS) individuals. Method: The research sample comprised 15 individuals (one female and 14 males), aged 8 to 46 years. The following procedures were used: medical history survey, otoscopy, speech and puretone threshold audiometry, acoustic immittance measures, and central auditory pathway assessment with brainstem auditory evoked potentials (BAEP) and long-latency auditory evoked potentials (LLAEP). Results: The pure-tone audiometry identified hearing loss in 13 individuals, and more than 90 % of the hearing loss was sensorineural. The degree of hearing loss was between mild to moderately severe with descendent configuration. Type A tympanogram predominated, and acoustic reflexes were present according to the types and degrees of hearing loss. Among the individuals with abnormal BAEP, longer wave III and V absolute latencies were the main findings. In addition, the unilateral absence of wave I was observed in two cases. In the LLAEP, longer latencies were observed in 14 individuals, and the most impaired components were the P1 and P3 in children and adolescents and the P2, N2 and P3 in adult individuals. Conclusion: The peripheral auditory pathway assessment revealed a predominantly sensorineural hearing loss, affecting mainly high frequencies, and in the central pathway was observed abnormal brainstem and cortical auditory processing in individuals with MPS.