de Boer Gillian, Bressmann Tim
Cleft Palate Craniofac J. 2014 Jan;51(1):90-7. doi: 10.1597/12-202. Epub 2013 Apr 3.
The study had the goal of comparing the new Nasometer 6450 to the older model 6200 using synthetic test sounds and control participants. A particular focus of the investigation was on the test-retest variability of the instruments.
The Nasometers 6200 and 6450 were compared using square wave test sounds. Six repeated measurements of oral, balanced, and nasal test stimuli were recorded from 25 female participants over an average of 35 days.
The synthetic test sounds demonstrated that the two nasometers obtained similar results for a range of frequencies. The results for the clinically normal participants revealed that nasalance scores from the two instruments were within 1-2 points, depending on the test sentence. Variability in scores increased with the proportion of nasal consonants in the sentence. Test-retest variability was between 6 and 8 points for more than 90% of the participants. Participants with higher nasalance scores for oral stimuli had higher between-session variability.
The Nasometers 6200 and 6450 should yield comparable results in clinical practice. Depending on the phonetic content of the test materials, clinicians should allow for a 6- to 8-point between-session variability when interpreting nasalance scores.
