Comparison of short-term and long-term variability in nasalance scores

To evaluate long-term nasalance score variability while accounting for short-term variation associated with subject performance and headgear change variability. STIMULI: Turtle and Mouse Passages.

Short-term immediate test-retest nasalance score variability was assessed with no headgear change (NCHG) and with change of headgear (CHG). Long-term variability was assessed with scores obtained in the morning and afternoon of the same day, 1 day apart, and 1 week apart. Scores from the long-term conditions necessarily reflect variability associated with headgear change plus variability, which may be attributed to time.

Twenty-six adults (19 to 70 years of age) with normal speech and resonance.

Forty-six nasalance scores per subject.

Mean nasalance difference scores across conditions were compared. Three contrasts were significantly different, each involving comparison of nasalance difference scores in the NCHG condition to difference scores from a CHG condition. Overall, long-term variability was slightly greater than short-term variability. For the Turtle Passage, in the short-term CHG condition, 92% of repeated scores were within five points. In the long-term conditions, 83% to 89% of scores were within five points. For the Mouse Passage, 88% of repeated scores in the CHG condition were within five points. In the long-term conditions, 81% to 83% of scores were within five points.

Nasalance scores obtained over time showed slightly greater variability than scores obtained in immediate test-retest conditions; however, variability did not increase as the length of time between measures increased.