Effect of Stimulus Length on Nasalance Scores

OBJECTIVE: Nasalance measures were compared for speech stimuli of four different lengths. DESIGN: The standard for comparison was a 44-syllable passage. The 44-syllable passage was compared to a 17-syllable passage, a 6-syllable sentence, and a 2-syllable word. All stimuli were devoid of nasal consonants and were composed only of low pressure consonants and vowels. SETTING: Academic and clinical craniofacial center. SUBJECTS: The subjects were 20 children at risk for velopharyngeal dysfunction and 5 children without history of communication disorder. MAIN OUTCOME MEASURE(S): The main outcome measures were the nasalance scores associated with speech samples of different lengths. RESULTS: The results showed that comparable measures of nasalance can be obtained using stimuli as short as a six-syllable sentence. Both the 17-syllable and the 6-syllable stimulus achieved high criterion validity, indicating that stimuli of that length could be substituted for the longer 44-syllable passage. The two-syllable word, however, had significantly lower criterion validity and could not be used to obtain valid estimates of nasalance. CONCLUSION: Valid assessment of nasalance can be achieved with speech samples as short as six syllables.