title: Assessment of hearing loss by pure-tone audiometry in patients with mucopolysaccharidoses.
abstract: BACKGROUND
  Patients with mucopolysaccharidoses (MPS) often have hearing loss. However, the characterization of hearing loss by pure-tone audiometry (PTA) in this rare disease population and its relationship to age and treatment is limited.
  
  
  METHODS
  PTA was performed in 39 patients with MPS (29 males and 10 females; 3 with MPS I, 21 with MPS II, 9 with MPS IVA, and 6 with MPS VI; median age, 11.9 years; age range, 4.4-34.2 years). The degree of hearing loss was classified by the age-independent World Health Organization (WHO) clinical guidelines.
  
  
  RESULTS
  Hearing loss by PTA was present in 85% (33/39) of patients and was categorized as mild (26-40 dB) in 18%, moderate (41-60 dB) in 36%, severe (61-80 dB) in 23%, and profound (≥81dB) in 5%. Among the patients with hearing loss, 33% were classified as mixed type (conductive and sensorineural), 30% as pure conductive type, 27% as pure sensorineural type, and 9% were undefined. The means of the right and left ear hearing thresholds at 2000 and 4000 Hz by air conduction (AC) and at 500, 1000, 2000, and 4000 Hz by bone conduction (BC) were all positively correlated with age (p<0.05). In the 6 patients with MPS II or VI who underwent follow-up PTA after ventilation tube insertion and enzyme replacement therapy for 1.9 to 8.5 years, all showed improvements in AC and BC of the better ear, as well as in the air-bone gap.
  
  
  CONCLUSIONS
  Hearing impairment is common in MPS. Early otolaryngological evaluation and intervention are recommended. These findings and the follow-up data can be used to develop quality of care strategies for patients with MPS.
authors.affiliation: Department of Medicine, Mackay Medical College, New Taipei City, Taiwan; Department of Pediatrics, Mackay Memorial Hospital, Taipei, Taiwan; Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan; Mackay Junior College of Medicine, Nursing and Management, Taipei, Taiwan; Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Hsiang-Yu
authors.initials: HY
authors.lastname: Lin
authors.affiliation: Department of Medicine, Mackay Medical College, New Taipei City, Taiwan; Division of Gastroenterology, Department of Internal Medicine, Mackay Memorial Hospital, Taipei, Taiwan.
authors.forename: Shou-Chuan
authors.initials: SC
authors.lastname: Shih
authors.affiliation: Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan; Medical College, Fu-Jen Catholic University, Taipei, Taiwan; Institute of Biotechnology, National Taipei University of Technology, Taipei, Taiwan.
authors.forename: Chih-Kuang
authors.initials: CK
authors.lastname: Chuang
authors.affiliation: Department of Medicine, Mackay Medical College, New Taipei City, Taiwan; Mackay Junior College of Medicine, Nursing and Management, Taipei, Taiwan; Department of Otorhinolaryngology, Mackay Memorial Hospital, Taipei, Taiwan; Department of Audiology & Speech Language Pathology, Mackay Medical College, New Taipei City, Taiwan.
authors.forename: Kuo-Sheng
authors.initials: KS
authors.lastname: Lee
authors.affiliation: Department of Medicine, Mackay Medical College, New Taipei City, Taiwan; Department of Pediatrics, Mackay Memorial Hospital, Taipei, Taiwan; Mackay Junior College of Medicine, Nursing and Management, Taipei, Taiwan.
authors.forename: Ming-Ren
authors.initials: MR
authors.lastname: Chen
authors.affiliation: Department of Medicine, Mackay Medical College, New Taipei City, Taiwan; Department of Otorhinolaryngology, Mackay Memorial Hospital, Taipei, Taiwan; Department of Audiology & Speech Language Pathology, Mackay Medical College, New Taipei City, Taiwan.
authors.forename: Hung-Ching
authors.initials: HC
authors.lastname: Lin
authors.affiliation: Department of Pediatrics, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
authors.forename: Pao Chin
authors.initials: PC
authors.lastname: Chiu
authors.affiliation: Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Pediatrics, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Dau-Ming
authors.initials: DM
authors.lastname: Niu
authors.affiliation: Department of Medicine, Mackay Medical College, New Taipei City, Taiwan; Department of Pediatrics, Mackay Memorial Hospital, Taipei, Taiwan; Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan; Mackay Junior College of Medicine, Nursing and Management, Taipei, Taiwan; Department of Infant and Child Care, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan. Electronic address: zsplin14@gmail.com.
authors.forename: Shuan-Pei
authors.initials: SP
authors.lastname: Lin
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D034381:Hearing Loss / Q000150:complications* / Q000175:diagnosis* / Q000453:epidemiology; D006801:Humans; D008297:Male; D009083:Mucopolysaccharidoses / Q000150:complications*; D015995:Prevalence; D055815:Young Adult
keywords: Enzyme replacement therapy; Hearing loss; Mucopolysaccharidoses; Pure-tone audiometry