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2016-10-16 - Colloque/Présentation - poster - Anglais - 1 page(s)

Verhaegen Clémence , Delvaux Véronique , Fagniart Sophie , Huet Kathy , Piccaluga Myriam , Harmegnies Bernard , "Phonetic and/or phonological paraphasias in aphasia: an acoustic study of speech output in two aphasic patients" in 54th academy of aphasia conference, Llandudno, Royaume-Uni, 2016

  • Codes CREF : Psycholinguistique (DI5321), Phonétique (DI5312), Logopédie (DI3355), Traitement du langage (DI4299), Phonologie (DI5311)
  • Unités de recherche UMONS : Métrologie et Sciences du langage (P362)
  • Instituts UMONS : Institut de recherche en sciences et technologies du langage (Langage)
Texte intégral :

Abstract(s) :

(Anglais) In aphasia, the phonological or phonetic origin of language production errors affecting phonemes is often discussed. However, the distinction between phonological and phonetic paraphasias is generally based on perceptual analyses that could be influenced by the experimenter’s perceptual system and/or expectations (Marczyk & Baqué, 2013). In our study, in order to distinguish between these paraphasias, by means of evidence-based procedures, we conducted acoustic analyses of the productions of two French-speaking aphasic patients, CL (aged 65) and TM (aged 62). Both patients were non fluent and produced errors affecting phonemes on a picture description and a picture naming task. We mainly focused on the analyses of voice onset time (VOT) in stop consonants, a reliable cue of motor speech control that may be affected in patients with phonemic impairment (Laganaro, 2015). We assumed that in case of phonetic deficits, patients would experience difficulties to coordinate their articulators and to maintain both voicing and supra-glottal closure, especially for French voiced stops that have a long and negative VOT (as defined by Lisker & Abramson, 1964). Therefore, we may observe a great tendency to devoice voiced stops in these patients or VOT values that fell between the voiced and voiceless categories in French. On the other hand, in case of phonological deficit, patients would experience difficulties to select phonemes within the phonological system, leading to no clearly-established tendency in voicing errors (Blumstein, Cooper, Goodglass, Statlender, & Gottlieb, 1980; Nespoulous, Baqué, Rosas, Marczyk & Estrada, 2013). Patients’ VOT durations were analyzed in a repetition task of 84 CVCV non-words, including the six French stop consonants /p,t,k,b,d,g/ combined with the three cardinal vowels /a,i,u/. VOT was estimated for each CV couple. Table 1 shows VOT values for each patient in consideration of the expected type of consonant (voiced or voiceless). The presence of voicing in the consonant was evidenced by the observation of periodicity in the spectrogram. The binary decision (voiced/voiceless) was taken on the basis of numerical criteria involving zero-crossing and HNR ratios, allowing to put emphasis on discrete and possibly infra-clinic attempts of voicing. The results showed voicing difficulties in both patients suggesting phonetic impairment. For instance, as indicated on Table 1, CL showed a great tendency to devoice voiced stops while TM presented shorter VOT values for voiced stops (Laeufer, 1996). Moreover, we also observed great diversity in the manifestations of the patients’ difficulties as well as palliative strategies used by the patients to compensate for their voicing difficulties in voiced stops. These mechanisms suggest that our patients correctly selected the target phoneme within the phonological system but had difficulties to produce it at the phonetic level. Our results reveal the importance of conducting acoustic analyses in order to distinguish between phonetic and phonological errors. Moreover, the great diversity in the patients’ production highlights the need to use multiple acoustic measures and indexes to objectify the observed phenomena.

Mots-clés :
  • (Anglais) phonological errors
  • (Anglais) aphasia
  • (Anglais) phonetic errors