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Speech error analysis in isolated Apraxia of Speech may reveal subtypes: evidence from two stroke case studies

Claudia Cramer1*, Naianna Robertsson1, 2, Stephanie J. Forkel1 and Marco Catani2*
  • 1 Natbrainlab, United Kingdom
  • 2 Natbrainlab, Department of Forensic and Neurodevelopmental Sciences and The Sackler Institute for Translational Neurodevelopment, United Kingdom

Apraxia of Speech (AOS) is a motor speech disorder characterised by incoordination of the speech musculature (Wertz et al., 1984). AOS typically arises following stroke, often co-occurring with aphasia and dysarthria, making differential diagnosis challenging (Darley et al., 1975). Diadochokinetic (DDK) rate is a principal assessment used to detect AOS by examining incoordination of tongue movements (Wertz et al.,1984). However, incoordination of other elements of speech production, such as phonatory sequencing for voiced/voiceless contrasts, have not been assessed with DDK. In this study speech errors of two acute stroke patients with isolated AOS were analysed to explore quality of errors, sensitivity of DDK in its current form and consequently, to infer potential functional specificity of lesion sites based on error types. METHOD: CW (age 60, right-handed female) and BF (age 25, left-handed male) were recruited during the acute stage of stroke. Routinely-acquired clinical scans (CT, MRI) were collected for both patients to determine lesion site. AOS was assessed using the Motor Speech Evaluation (MSE): Oro-motor exam and DDK (Wertz et al., 1984), Western Aphasia Battery-Revised (WAB-R) repetition subtest (Kertesz, 2007), Rainbow passage (connected speech sample generated through reading; Fairbanks, 1960) and the Cinderella Story (spontaneous speech sample). Aphasia (WAB-R) and dysarthria (MSE) were ruled out and a Speech and Language Therapist conducted all assessments. Speech errors were phonetically transcribed and categorised by type (e.g. articulatory substitution, phonatory substitution, addition etc.). RESULTS: Lesion sites: CW, left posterior inferior frontal gyrus focal haematoma. BF, left frontal operculum infarct extending superiorly towards the pre-central gyrus. MSE: Both patients had impaired DDK sequencing, where production of isolated phonemes was preserved. Oro-motor exams were unremarkable and thus both patients were classified as having isolated AOS. Speech error analysis: CW produced errors consisting mainly of articulatory substitutions (50%) across both speech samples and was more likely to produce omission errors in spontaneous speech (25% as compared to 13.6% in connected speech) and addition errors in connected speech (27.3% as compared to 8.3% in spontaneous speech). BF produced errors consisting mainly of vowel distortions (28% in spontaneous speech; 35% in connected speech) and was more likely to produce phonatory substitutions in connected speech (21.4%) than in spontaneous speech (3.9%). Unlike CW, BF displayed syllable segmentation behaviours throughout both speech samples. Both patients were more likely to self-correct their errors in connected speech (percentage of errors corrected - CW, 59.1%; BF, 28.57%) compared to spontaneous speech (percentage of errors corrected -CW, 29.2%; BW, 3.9%). This suggests that self-monitoring is improved during oral reading. CONCLUSION: Our preliminary findings show that speech error analysis reveals different presentations of AOS that were not detected by DDK, supporting the notion of AOS sub-types (Josephs et al., 2013). DDK assessments that analyse articulation and phonation incoordination may be more useful in interpreting AOS presentation. Moreover, our findings suggest that oral reading could influence the type of errors produced and increase self-monitoring behaviours as compared to spontaneous speech. Analysis into type of substitution errors may also reveal a functional specificity for lesion site in relation to tract pathways and could explain why past research has identified numerous regions in the left hemisphere associated with AOS (Hillis et al., 2004; Dronkers, 1996; Duffy, 1995; Peach and Tonkovich, 2004; Rueckert et al., 1994; Josephs et al., 2014). Future studies with greater participant numbers are needed to establish the validity and sensitivity of these findings.

References

Darley, F. L., Aronson, A. E., & Brown, J. R. (1975). Motor speech disorders. Philadelphia: Saunders.

Dronkers, N. F. (1996). A new brain region for coordinating speech articulation. Nature, 384, 6605, 159-61.

Duffy, J. R. (1995). Motor speech disorders: Substrates, differential diagnosis, and management. St. Louis: Mosby.

Fairbanks, G. (1960). Voice and articulation drillbook. New York: Harper.

Hillis, A. E., Work, M., Barker, P. B., Jacobs, M. A., Breese, E. L., & Maurer, K. (2004). Re-examining the brain regions crucial for orchestrating speech articulation. Brain, 127, 1479-87.

Josephs, Keith A., Duffy, Joseph R., Strand, Edythe A., Machulda, Mary M., Senjem, Matthew L., Lowe, Val J., Jack, Clifford R., ... Whitwell, Jennifer L. (2013). Syndromes dominated by apraxia of speech show distinct characteristics from agrammatic PPA. Neurology, 81, 4, 337-345

Josephs, Keith A., Duffy, Joseph R., Strand, Edythe A., Machulda, Mary M., Senjem, Matthew L., Gunter, Jeffrey L., Schwarz, Christopher G., ... Whitwell, Jennifer L. (2014). The evolution of primary progressive apraxia of speech. Brain, 137; 2783–2795
Kertesz, A., & Raven, J. C. (2007). WAB-R: Western Aphasia Battery-Revised. San Antonio, TX: PsychCorp.

Peach, R. K., & Tonkovich, J. D. (2004). Phonemic characteristics of apraxia of speech resulting from subcortical hemorrhage. Journal of Communication Disorders, 37, 1, 77-90.

Rueckert, L., Appollonio, I., Grafman, J., Jezzard, P., Johnson, R., Le Bihan, D., & Turner, R. (1994) Magnetic resonance imaging functional activation of left frontal cortex during covert word production. J Neuroimaging, 4, 2, 67-70.

Wertz, R. T., LaPointe, L. L., & Rosenbek, J. C. (1984). Apraxia of speech in adults: The disorder and its management. Orlando: Grune & Stratton.

Keywords: apraxia of speech, Motor speech disorder, Stroke, diadochokinesia, speech error analysis

Conference: 54th Annual Academy of Aphasia Meeting, Llandudno, United Kingdom, 16 Oct - 18 Oct, 2016.

Presentation Type: Poster Sessions

Topic: Academy of Aphasia

Citation: Cramer C, Robertsson N, Forkel SJ and Catani M (2016). Speech error analysis in isolated Apraxia of Speech may reveal subtypes: evidence from two stroke case studies. Front. Psychol. Conference Abstract: 54th Annual Academy of Aphasia Meeting. doi: 10.3389/conf.fpsyg.2016.68.00058

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Received: 29 Apr 2016; Published Online: 15 Aug 2016.

* Correspondence:
Ms. Claudia Cramer, Natbrainlab, London, United Kingdom, claudia.cramer@kcl.ac.uk
Dr. Marco Catani, Natbrainlab, Department of Forensic and Neurodevelopmental Sciences and The Sackler Institute for Translational Neurodevelopment, London, United Kingdom, marco.1.catani@kcl.ac.uk