University of Texas at Dallas

1. University of Texas at Dallas Callier Center for Communication Disorders

2. Principles of motor learning applied to the treatment of apraxia of speech (AOS) William F. Katz, Ph.D. Thanks also to: Diane Garst, M.S., CCC-SLP June Levitt, ‘A.B.D’ Sneha Bharadwaj, Ph.D.

3. Course overview • Review of AOS – signs, symptoms, theoretical bases • Introduction to motor learning theory (MLT) • EMA – a non-invasive means of tracking speech movement • Experimental use of EMA in treating AOS • Future directions and challenges

4. Course overview • Review of AOS – signs, symptoms, theoretical bases • Introduction to motor learning theory (MLT) • EMA – a non-invasive means of tracking speech movement • Experimental use of EMA in treating AOS • Future directions and challenges

5. Definitions/ Types • Praxis: Performance of an action • Apraxia: “without action” • Major types: • Limb apraxia • Oral apraxia (buccofacial) • Apraxia of speech

6. Ideational vs. Ideomotor Apraxia • Ideational - Inability to use an object or gesture due to loss of knowledge of the object’s function (Conception problem) • Ideomotor - Deficit carrying out the motor plan needed to use an object or make a gesture (Performance problem) 

7. History of Apraxia • H. Liepmann • 1900 report described limb apraxia, difficulty sequencing limb movement • Also, description of speech sequencing difficulties • K. Wernicke • Described nonverbal oralapraxia in 1906 (1863-1925) (1848 -1905)

8. Classic and Contemporary Definitions of AOS • Darley (1967) • Neurogenic-based speech disorder existed that was NOT dysarthria or aphasia • Revisit AOS characteristics to differentiate from clinical neighbors (e.g. dysarthrias and phonemic paraphasias of aphasia)

9. Boston school vs. Mayo Clinic Apraxia of Speech.. Broca’s Aphasia..

10. Apraxia of Speech • Deficit in the ability to smoothly sequence the speech producing movements of the tongue, lips, jaw, and velum. • Primarily affects articulation and prosody.

11. Speech Production Model “The practicing clinician can use a coherent model to put diagnosis, differential diagnosis, and management on a sound theoretical basis” (Van der Merwe, 1997)

12. Speech Sensorimotor Control • Stage 1: Linguistic-Symbolic Planning • Stage 2: Motor Planning • Stage 3: Motor Programming • Stage 4: Execution

13. Stages Disorders

14. Recent definition of AOS(Academy of Neurologic Communication Disorders and Sciences, ANCDS) • A neurogenic speech disorder characterized by • Erroneous production of speech sounds • Reduced rate of speech • Increased time in transitioning between sounds, syllables, and words • Disordered prosody

15. ANCDS definition - cont’d • May be accompanied by: • Articulatory groping • Difficulty initiating speech • Increasing number of sound errors with increasing word length • Motoric perseverations • Severity ranges from a complete inability to speak to minimal disruptions in speech production.

16. Etiology • Most common: • Stroke • Brain Injury • Degenerative disease • Patients often describe: “I know what I want to say, I just can’t get it out.”

17. Other Facts • Usually left hemisphere lesion • Frequently co-occurs with other neurogenic disorders • Mayo Clinic reported cases of AOS 83% with Oral apraxia 81% with Aphasia 31% with Dysarthria • “Pure” AOS is very rare

18. AOS Clinical Characteristics: Primary • Sound distortions • Consonants and vowels • Slow speech rate: • Lengthened segments (vowels and/or consonants) • Lengthened intersegment durations between sounds, syllables, words, phrases: possibly filled with intrusive schwa

19. AOS Clinical Characteristics: Primary – Cont’d • Distorted sound substitutions • Errors are relatively consistent in type (e.g. substitutions, omissions, distortion) and location in repeated utterances • Prosodic abnormalities

20. Clinical Characteristics: Nondiscriminative • Articulatory groping: audible and/or visible and probably distorted relative to the target • Perseverative errors (perseveration of movement pattern) • Increasing errors with increasing word length • Speech initiation difficulties

21. Clinical Characteristics: Nondiscriminative - cont’d • Awareness of errors (self-correction) • Automatic speech better than propositional speech • Islands of error-free speech

22. Course overview • Review of AOS – signs, symptoms, theoretical bases • Introduction to motor learning theory (MLT) • EMA – a non-invasive means of tracking speech movement • Experimental use of EMA in treating AOS • Future directions and challenges

23. Development of Motor Skill Learning Theory Early studies -- (introspection) Developing need/ applications Emergence of theories.

24. Schema Theory(Schmidt, 1975) Generalized Motor Program (GMP) Outcomes Parameters “Write your name” Schema

25. Motor learning is affected by: • type of feedback • amount of repetitive practice • practice schedule • cognitive condition

26. Intrinsic and Extrinsic feedback • Intrinsic The sensory information: natural consequence of producing a movement • Extrinsic “Augmented feedback”: provided from sources outside of the learners’ bodies

27. Extrinsic (Augmented) feedback • Knowledge of Result (KR) KR describes the outcome. “It was correct.” • Knowledge of Performance (KP) KP describes movement quality. “Your arm was too high for this shot...”

28. Kinematic Feedback • “kinematic” = pure motion. • Information about movement that the learner cannot directly perceive. • Instructor’s comments • Display on computer monitor

29. De Nil & Lafaille (2002) Examined whether the presence of visual kinematic feedback differently influences the accuracy of finger and jaw movements (in healthy adults) Limb/speech motor control parallels?Sample evidence Results: KP reduced error for both finger and jaw movements without KP with KP

30. AOS / Motor learning theory ? ? GMP Outcomes Parameters Schema

31. Therapies suggesting a role for awareness of articulatory movement PROMPT ‘Prompts for Restructuring Oral Muscular Phonetic Targets’ Touch-Cue

32. Facial PROMPTS(Square et al., 1986; Freed et al., 1997)

33. PROMPT: Lingual placement

34. Course overview • Review of AOS – signs, symptoms, theoretical bases • Introduction to motor learning theory (MLT) • EMA – a non-invasive means of tracking speech movement • Experimental use of EMA in treating AOS • Future directions and challenges

35. Electromagnetic Midsagittal Articulography (EMA or EMMA) • 2-d recording of articulator position & speed • Midsagittal view - tongue, lips, jaw (and possibly velum) • Accuracy of 0.1 mm • Synchronized speech signal recorded to disk • Measures up to 15 data channels in midsagittal plane

36. EMA - Receiver coil placement

37. Katz, Bharadwaj & Stettler, JSLHR, 49, 3, 1-15, 2006

38. EMA – How it works • Three transmittercoils in helmet • These generate alternating electromagnetic fields at different frequencies • Receiver coils (sensors) are placed on the subject’s articulators along the midsagittal plane. • Induced voltages are sampled at a relatively high frequency • The position of each sensor can be calculated as the point where the radii from thethree transmitters intersect.

39. EMA – Need for exact midsagittal alignment • If a sensor is rotated away from a parallel orientation, then the induced voltage declines -- resulting in over-estimation of the distances. • If in proper parallel alignment but outside the midsagittal plane, then the distance will also be distorted.

40. EMA – sample display

41. Visual Feedback Configuration

42. On-line EMA for kinematic feedback (Screenshot)

43. Biofeedback:Target and Active areas are set for each subject Note: This particular example is from a study of nonspeech (oral) apraxia Target Area 1 (for upper lip) Active Area (home position) Target Area 2 (for lower lip)

44. Initial EMA intervention studies

45. REPORT #1"Electromagnetic articulography treatment for an adult with Broca's aphasia and apraxia of speech" • (1999) Journal of Speech, Language, and Hearing Research, 42, 1355-1366

46. Subject • 63-year-old female • Rt handed, monolingual, native GAE speaker • Large, left MCA CVA • Broca’s aphasia with slight BF apraxia and moderate-to-severe AOS • Had received for 8 years of conventional speech therapy by time of testing

47. Assessment items • Monosyllabic words pick tick pit kit • Polysyllabic words vision fatherly seafood cantaloupe • Short functional phrases Just go. Please show me some.

48. Experimental design • Particular problems noted for the sounds [dZ], [s], [S], [j], and [t]  • Treat [s], [S] with experimental method (EMA) • Treat [d] and [t] with placebo method

49. Experimental Procedure – Supervised motor learning • Subject’s goal was to ‘hit the targets’ shown on the monitor • Each time a target was hit, a tone was heard and a visual reward (a rising balloon) moved on the monitor • Thus, subject received continuous visual (and auditory) augmented feedback during the non-speech gesture task • In each trial, a target zone lit up green, indicating the subject should move the tongue-tip coil into that region • Immediately after this target zone was hit, it turned red, and the alternate target lit up green • Subject was required to hit all target zones displayed on the monitor before being thanked (by the computer) for finishing each task.

50. Experimental treatment (screenshot)