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Why is speech rate slow in nonfluent/agrammatic primary progressive aphasia?
Poster A3 in Poster Session A, Thursday, October 6, 10:15 am - 12:00 pm EDT, Millennium Hall
Sharon Ash1, Naomi Nevler1, Murray Grossman1; 1Perelman School of Medicine of the University of Pennsylvania
BACKGROUND: The diagnostic criteria for nonfluent/agrammatic primary progressive aphasia (naPPA) include “effortful, halting speech…” but the features that constitute such speech are not specified. It is well known that individuals with naPPA pause more while speaking than healthy individuals do, but other durational characteristics of naPPA speech are less well characterized. In this study, we examined durational features of individual words as well as pauses in connected speech to contribute to the understanding of slowed speech rate in naPPA. METHODS: We analyzed spontaneous, connected speech elicited by descriptions of the Cookie Theft scene in individuals with naPPA (N=30), behavioral variant frontotemporal degeneration (bvFTD) (N=22) as a brain-damaged control group, and healthy controls (HC) (n=16), matched for age, education, and sex. The two patient groups were also matched for disease duration. We automatically measured the durations of all words and pauses between words. We compared the durations of identical words spoken by the participants and the frequency and durations of pauses ≥ 150 msec occurring between words within independent clauses and their associated dependent clauses. Words were sorted by part of speech to investigate the possible effect of grammatical category on variation in word duration. RESULTS: The mean (±SD) speech rates in words per minute of individuals with naPPA, bvFTD, and HC were 61±27, 94±40, and 143±33, respectively. naPPA patients were significantly slower than both bvFTD and HC (p<.01), and bvFTD patients were slower than HC (p<.01). The durations of identical words in naPPA compared to both bvFTD and HC were significantly greater for all nouns (N=29, e.g., cookie), verbs (N=32, e.g., see), pronouns (N=15, e.g., she), determiners (N=9, e.g., the), and prepositions (N=17, e.g., of) (p<.01 for all comparisons). For adverbs (N=10, e.g., very), the duration for naPPA vs. bvFTD and HC was also significantly greater (p<.05). For the few identical adjectives (N=2, e.g., open) and conjunctions (N=4, e.g., and) that could be compared among the 3 participant groups, naPPA showed the longest durations but the differences between naPPA and the other groups were not significant. There were no significant differences in word duration between bvFTD and HC for any of the words that could be compared among groups. The mean duration of pauses between words was greatest for bvFTD (1307±1469 msec) but was not significantly different from the mean duration of pauses in naPPA (894±402 msec) or HC (697±266 msec). The mean frequency of pauses between words in naPPA was 36.3±17.8 per 100 words, compared to 12.6±6.3 per 100 words in bvFTD and 9.3±4.1 in HC. This frequency of pauses between words in naPPA was significantly greater than that in both bvFTD and HC (p<.01). CONCLUSIONS: Speech rate in naPPA is slowed by overall lengthening of the duration of words, which occurs regardless of grammatical category. The lengthening of word duration is unique to naPPA, in contrast to bvFTD and HC. In addition, naPPA speech is slowed by a higher frequency of pauses between words compared to other groups, but not by a greater duration of pauses.
Topic Areas: Language Production, Disorders: Acquired