title: Voice Mutation During Adolescence in Mangalore, India: Implications for the Assessment and Management of Mutational Voice Disorders.
abstract: BACKGROUND
  The knowledge of vocal mutation is important for speech pathologists in the diagnosis and management of individuals with mutational voice disorders. However, data on vocal mutation in the Indian population are scarce and hence the present study was planned to investigate the age of attainment of vocal mutation in boys and girls from Mangalore, India, in the age range of 8-18 years.
  
  
  METHODS
  A total of 600 participants in the age range of 8-18 years were divided into 10 groups with a 1-year interval. Sustained phonation /a/ and a narration were recorded. Two-way analysis of variance was used to obtain significant difference between the means across age and gender for the fundamental frequency and formant frequency measures.
  
  
  RESULTS
  There was significant main effect of groups for fundamental frequency measure in boys, with post hoc tests revealing statistically significant differences from 14 years of age onward. However, the cutoff criteria of 140 Hz in boys and 240 Hz in girls were attained only by 16 years of age in boys and 15 years in girls, indicating that 16 and 15 years as the ages of onset of vocal mutation in boys and girls, respectively. Results also revealed that first formant frequency undergoes changes from 13 years onward. However, F2 changes from 16 years of age, with no significance observed in F3.
  
  
  CONCLUSIONS
  The results of the present study are useful in the assessment and management of individuals with mutational voice disorders.
authors.affiliation: Department of Audiology and Speech Language Pathology, Kasturba Medical College (Manipal University), Mangalore, Karnataka 575001, India. Electronic address: radheesh_b@yahoo.co.in.
authors.forename: Radish Kumar
authors.initials: RK
authors.lastname: Balasubramaniam
authors.affiliation: Department of Audiology and Speech Language Pathology, Kasturba Medical College (Manipal University), Mangalore, Karnataka 575001, India.
authors.forename: Nikhita
authors.initials: N
authors.lastname: N
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007194:India; D008297:Male; D014831:Voice; D014832:Voice Disorders
keywords: Acoustic analysis; Formant frequency; Fundamental frequency; Mutational voice disorders; Vocal mutation