Nine researchers from the University of Pennsylvania’s School of Medicine report results of a study into the prevalence and presentation of apraxia of speech (AoS) phenomena in the spontaneous, connected verbal productions of persons with nonfluent/agrammatic primary progressive aphasia (naPPA). The two goals of their investigation were: [1] to assess the types and frequencies of features of AoS in individuals with naPPA, and [2] to study whether or not these features are caused by a motor disorder associated with a additional diagnosis of extrapyramidal disease in these study subjects.
The researchers used picture description tasks to elicit speech samples from three groups — thirty persons with naPPA, twenty two persons with frontotemporal dementia associated with behavioral but not speech-language involvement, and 30 age- and gender-matched neurotypical individuals. The speech samples were examined for such features as unusual segment lengthening, distortions of speech sounds, pauses within and between words, and articulatory groping behaviors during production. The 30 subjects with naPPA were screened for corticobasal syndrome, and further divided into subgroups based on whether or not at least two of AoS behaviors were observed, in order to assess whether speech production deficits were correlated with co-occurring extrapyramidal motor impairments.
Data analyses show that – while lengthening of speech segments was uncommon – other types of distortions and deficits of production were not. For example, 90% of persons with naPPA paused within and between words more often – and for longer – than normal. Articulatory groping characterized production attempts in 20% of this group (6/30), qualitative sound distortions were observed in over a quarter (8/30), and the remaining types of production deficits were observed in 60% (18/30) of this group. Comparison of the contrasting subgroups within these PPA subjects – those presenting with and without cortocobasal syndrome – revealed no signficicant differences in the frequencies of AoS features in their spontaneous speech. Study of these AoS phenomena in the other comparison groups — age- and gender-matched neurotypical individuals, and age- and gender-matched individuals with frontotemporal dementia without speech-language involvement — showed no distortions or deficits of clinical significance. The authors conclude that features of AoS occur with varying frequencies in the spontaneous speech of persons with naPPA, independently of co-occurring motor disorder contributions.
For further reading: S. Ash, N. Nevler, D. J. Irwin et al., 2023,
Apraxia of speech in the spontaneous speech of nonfluent/agrammatic primary progressive aphasia. Journal of Alzheimer’s Disease Reports, 7(1): 589–604
DOI: 10.3233/ADR-220089