Laryngeal Diadochokinesis Across the Adult Lifespan.

Diadochokinetic tasks provide valuable clinical information regarding neuromuscular control and coordination. Laryngeal diadochokinesis (LDDK) has the potential to provide insight into the neuromotor functioning of the larynx, but interpretation is limited because of sparse normative data. This study provides normative data for LDDK tasks across the adult lifespan in men and women. Neurologically and vocally normal women (n = 216) and men (n = 188), ages 20–89 years, produced rapid repetitions of /ʔʌ/ and /hʌ/ to assess adductory and abductory laryngeal articulatory coordination, respectively. Outcome variables included average rate and regularity (% jitter) from a 5-second sample using a commercially available data acquisition and analysis system and verified by hand. Analyses of variance examined the data for task, sex, and age by decade. LDDK rate decreased significantly with age (F[6,390] = 10.67, P < 0.001) but variability did not differ systematically across age (F[6,390] = 0.595, P = 0.734). Neither LDDK rate nor variability differed significantly between the sexes (F[1,390] = 0.938, P = 0.334; F[1,390] = 0.050, P = 0.824, respectively). The tasks differed in that LDDK for /ʔʌ/ was significantly faster than for /hʌ/ (F[1,390] = 7.237, P = 0.007), but they did not differ significantly for variability (F[1,390] = 0.695, P = 0.405). No significant interactions were revealed. Normative data for LDDK tasks can be combined across the sexes. Separate norms should be used across age groups, especially for adults in their 20s and 80s, and across the two LDDK tasks. [ABSTRACT FROM AUTHOR]