Date of Award


Document Type


Degree Name

Master of Science (MS)


Special Education and Clinical Services

First Advisor

Lori Lombard, Ph.D., CCC-SLP

Second Advisor

David W. Stein, Ph.D., CCC-SLP

Third Advisor

Lisa Hammett Price, Ph.D., CCC-SLP


Measurement of laryngeal diadochokinesis (L-DDK) is used by speech-language pathologists to assess the fine motor function of the vocal folds. To date, research has been conducted using measures of L-DDK as assessment data, but normative data and standardized procedures are scant and inconsistent. Measurement of L-DDK has been found to facilitate early detection of various disorders and laryngeal abnormalities. Thus, normative L-DDK rates are necessary among all age groups in order for it to be used as a meaningful diagnostic tool. The current study focused specifically on the early adult population. Thirty-nine participants, both male and female, between the ages of 20 and 40 years were recruited for the study. Normative values were collected for L-DDK rate for the adductory task /ʌ/ and the abductory task /hʌ/ in adults between the ages of 20 and 40 years. Each participant was required to produce these L-DDK tasks for 7 seconds over three trials. The number of productions in 5 seconds of each trial was divided by five to calculate the rate per second. Rates for males and females are provided. Results also consider if there is a difference in rate between the L-DDK tasks (adductory task /ʌ/ and abductory task /hʌ/) as well as if there are differences in rates between males and females.