Presentation on theme: "Rosemary Varley Division of Psychology & Language Sciences"— Presentation transcript:
1 Building therapies on neurobiological principles Word-level therapy for apraxia of speech Rosemary VarleyDivision of Psychology & Language SciencesUniversity College London
2 Collaborators Sandra Whiteside & Patricia Cowell (HCS, Sheffield) Core research teamLucy Dyson; Lesley Inglis; Abigail RoperAdditional assistance from:Andrew Harbottle; Jenny Ryder; Vitor ZimmererAdditional collaboratorsSLTs across South Yorkshire, & in particular Rotherham NHSCatrin Blank (Clinical Neurology, NHS Sheffield)Tracey Young (ScHaRR, Health Economics, Sheffield)FundersThe Health Foundation; BUPA Foundation: University of Sheffield/HEIF4 knowledge transfer grants
3 Conflict of Interest Statement Sword Software Software program is commercially available‘Inventors’ Varley, Whiteside & Cookmartin receive share of royalties from sales
4 Post-Stroke Speech Production Impairments AnomiaLexical-semanticApraxia (AOS)Phonology-phoneticDysarthriaPhonetic
5 Generative-Computational Models of Speech & Language Minimise storage, maximise computation‘Elegant’, ‘Parsimonious’Phonology: store small number of units (phonemes, distinctive features e.g. [+ voice]) & large combinatorial mechanism to create syllablese.g., Shattuck-Hufnagel’s (1979) slots and fillers model
7 Apraxia of Speech (AOS) Under C-G view, underlying impairment:Inaccessible segmental plansImpairment of allocating segment to slotClassical apraxia therapy: microstructural (also articulatory-kinematic or sound production therapy)Rebuilding segmental plansPractice in generating cohesive syllables through combination of segmental plansi.e., subcomponents & generative mechanism
8 Example AOS & Microstructural Therapy Articulatory errors; Altered durational characteristics; Loss of speech automaticity; non-fluent, effortful, struggle & groping.
9 Evidence-Base for Microstructural Therapy Wambaugh, J. et al. (2006). J. Medical Speech-Language Pathology, 14(2), xv-xxxiii Treatment Guidelines for Acquired Apraxia of Speech: A Synthesis and Evaluation of the EvidenceMajority of research on articulatory therapiesLearning of targeted gesture/syllablePoor generalisation of learningExpensiveCochrane Review (2009): “No evidence was found for the treatment of AOS.”Therapists view as hard-to-treat condition.
10 Generative Models Under Attack At all levels of structural linguistic processing (phonology, morphology, syntax) generative-computational models under attackSyntax: I + am + go + ing + to + ____vs.Morphology: un + fortunate + lyPhonology y+e+s+t+er+d+ayNeurocognitive implausibility“human memory capacity is quite large” Bybee (2006: 717)I’m going to ____unfortunatelyyesterday
11 Alternative Model Usage/frequency-mediated models of processing Sequences which are frequently repeated become stored as complete units (complete words/ phrases/clauses)
12 Shattuck-Hufnagel’s puzzle & Levelt’s and paradox Shattuck-Hufnagel (1979): “perhaps [the] most puzzling aspect is the question of why a mechanism is proposed for the one-at-a-time serial ordering of phonemes when their order is already specified in the lexicon.”Levelt (1992) :“Why would a speaker go through the trouble of first generating an empty skeleton for the word, and then filling it with segments? In some way or another both must proceed from a stored phonological representation, the word’s phonological code in the lexicon. Isn’t it wasteful of processing resources to pull these apart first, and then to combine them again (at the risk of creating a slip).”
13 Re-thinking AOS via Frequency-mediated Account High frequency constructions stored as complete plans.Speech control (Crompton, 1982; Whiteside & Varley, 1998; Varley & Whiteside, 2001): frequently used output stored as complete phonetic plans.Biologically more plausible, and capable of delivering fast, cohesive and error-free movements.
14 Building Therapies on Neurobiological Principles (Varley 2011. Int. J Building Therapies on Neurobiological Principles (Varley Int. J. SLP)Frequency-mediated vs. computationalTherapy focuses on whole wordsProcedural vs. declarative learningInterconnectivity of processing systemsErrorless learning/error-reducing strategiesTherapy intensity (‘Dose’)- Illustrate with reference to AOS therapy
15 Procedural vs. Declarative Learning ‘Doing vs. Talking about doing’ Some speech/language interventions involve giving patient explicit knowledge of how (we think) speech/language systems operate i.e., metalinguistic knowledgeAssumption that patient will assimilate this explicit knowledge & ‘re-boot’ the automatic/procedural systems that govern listening & talkingIn the case of AOS, clinician shares explicit knowledge of articulatory phonetics – patient becomes patient becomes a ‘mini-phonetician’.But notice, most healthy speakers produce speech fluently without any awareness of phonetics
16 Procedural vs. Declarative Learning ‘Doing vs. Talking about doing’ Some speech/language interventions involve giving patient explicit knowledge of how (we think) speech/language systems operate i.e., metalinguistic knowledgeAssumption that patient will assimilate this explicit knowledge & ‘re-boot’ the automatic/procedural systems that govern listening & talkingIn the case of AOS, clinician shares explicit knowledge of articulatory phonetics – patient becomes patient becomes a ‘mini-phonetician’.But notice, most healthy speakers produce speech fluently without any awareness of phonetics
17 Procedural vs. Declarative Learning ‘Doing vs. Talking about doing’ Wulf et al (2001) Quarterly J Expt. Psych. Internal focus of attention leads to less automaticity in complex motor skill learning.Ballard et al (2011) Motor Control. Poorer retention of a novel speech movement in healthy speakers within kinematic feedback, than those without constant kinematic feedback.Possible link to learned misuse & constraint therapies: by making patient consciously aware of articulatory movements may result in learned non-use of usual automatic/procedural mechanisms of fluent speech control.
18 Interconnected of sensory-motor systems AOS therapy often uses nonsense syllables & pure production therapy (modules/autonomy)Observing movement results in sensory-perceptual activation, and ‘mirror’ activation in motor cortex (‘mirror neurons’, e.g. Wilson et al NatNeurosci).Fridriksson et al (2009, Stroke): therapy consisting of word-picture match + observing video of mouth resulted in improved word production in non-fluent aphasia.
22 Errorless Learning/Error-reduction Strategies (Whiteside et al. 2012 Errorless Learning/Error-reduction Strategies (Whiteside et al JNeuroRehab.)Errorful vs. Errorless/error reduction techniques.Errorless learning may be particularly important in procedural/motor learning. Errors prevent formation of stable movement memories.Therapy designed to minimise errors :Priming output via sensory-perceptual phaseImagined movement (Page et al. 2005)Immediate – Delayed Repetition – Independent production
23 Therapy Structure (Output: 7 modules) Observe video of speaker saying target wordImagined production of wordsImmediate repetition of words delayed repetitionRepetition with audio-recording & playbackPractise of target words in sentence framesProduction of word in isolation, with cue support if needed
25 Therapy Dose Pulvermüller & Berthier, 2008. Aphasiology. Neuronal plasticity & Hebbian learningHebb (1949) described how connections between synapses alter as a result of learning:“any two cells or systems of cells that are repeatedly active at the same time will tend to be become ‘associated’, so that activity in one facilitates activity in the other.” (1949, p. 70).Computer therapy cost-effective means of achieving necessary ‘dose’.
26 Therapy Study Therapy based on neurocognitive principles Computer therapy, allowing participants to self-administer intervention with potential to achieve high doseAdvised to use program regularly for short periods (‘little and often’)Program records user interactions50 participants with single therapy protocolSpeech intervention contrasted to sham/placebo computer intervention
28 Participants 50 participants with AOS (+ aphasia) recruited; 25 female: 25 maleMean age = 65 years>5 months post-LH-stroke (Mean = 22 months)44 participants completed studyVarying levels of computer experience (novice to expert).Participants randomly assigned to:Speech first (speech program – sham program) or,Sham first (sham program – speech program)No significant differences at baseline between two groups
29 Study Design Two period cross-over design (Cowell, et al. 2010 Study Design Two period cross-over design (Cowell, et al Frontiers in Human Neuroscience)Baselines 1-23-4 weeksPeriod 1Treatment 16 weeksRest4 weeksPeriod 2Treatment 26 weeksMaintenance8 weeksRestMaintenanceSham-FirstSHAMSPEECHSpeech-FirstSPEECHSHAM
30 Measures of BehaviourWord Production (35 in each set)Treated: ‘dog’Phonetically-matched, untreated: ‘door’Frequency-matched, untreated: ‘game’Performance measured in naming & repetitionAlso collected spontaneous speech samples at baseline & maintenanceUntreated behavioursWritten word-picture matching (PALPA 48, Kay et al., 1992)Spoken sentence-picture matching (CAT, Swinburn et al., 2004)Health Economic Assessment
31 Speech Analysis Word-level Repetition accuracy (0-7 scale) & word duration (fluency, cohesiveness of articulatory routines)7 = error-free, response latency <2 sec; normal word duration6 = error-free, response latency >2sec or slowed duration4 = one segment error2 = two segment error + groping0 = no response or off-targetNaming communicative adequacy (0/1) (would a naive listener understand the intended meaning?)
32 Blinding‘Open-label’ trial as not possible to blind clinician or participant to treatment being administered.Rater for word-level outcome measures blind to randomisation to speech-first/sham-first allocation.Inter-rater reliability check by further rater blinded to phase & rater 1 measurement (10% data).MeasureCorrelationRepetition accuracySpearman r=.892, p<.001Repetition durationPearson r=.956, p<.001NamingSpearman r=.912, p<.001
34 Compliance with ‘little and often recommendation’ Program use (hours:mins in 42 day period)Speech program: 3:32 – 50:29; M=16:48Sham program: 0:41 – 50:09; M=14:54No significant difference between sham/speech-first groups in level of use of either program11 participants completed entire speech program; 33 completed word-level production tasks.50 hours = 8 hours/week
35 Outcomes Summary Baseline behaviour was stable Untreated behaviours showed no significant change over course of studySpoken sentence-picture match (t(43)=-0.113, p=.911)Written word-picture match (t(42)=-1.017, p=.315)No spontaneous change in behaviourSham program had no influence on word production scores.Any treatment effect was not placebo
36 Results Format Sham-First Speech-First Post-Tx1 Baselines Post-Tx2 Maintenance
37 * Sham-First * Speech-First Naming Communicative Adequacy (Treated Words)*Sham-FirstSpeech vs. Sham program F(1,39)=14.486, p=0.0001)Treatment X Sequence interaction approached significance F(1,39)=4.006, p=0.052*Y axis: speech first 65% accuracy at baseline to 78% accuracy after speech intervention , 75% at maintenance.Speech-First
38 Repetition Accuracy - Treated *Speech>Sham program F(1,39)=4.562, p= No interaction with sequence*Speech first average score at baseline 5.3, post speech 6, maintenance 5.9.
39 Correct/Fluent scores across word sets (repetition) ns*Treated ‘dog’ns*nsFrequency-matched ‘game’Phonetically-matched ‘door’
40 Error/Struggle scores across word sets (repetition) *nsTreated ‘dog’nsnsFrequency-matched ‘game’Phonetically-matched ‘door’
41 High users (over 25 hours) Delta/change scoresBaseline = 0Post-tx = 7Delta 0 – 7 = -7High users (over 25 hours)Low users (under 10 hours)Low – under 10 hours: AOS hoursHigh – over 25 hours: 35 & 41 – 81 hours in total
42 Results Summary (1)Group level: significant improvement in naming & repetition accuracy of treated words following speech program, & improvements maintained weeks after withdrawal of therapy.Evidence of generalisation to phonetically-matched words.Pattern of response of speech-first group generally better than that of sham-first.
43 Results Summary (2) Individual differences in response Some high users showed improvement on both treated and untreated wordsOther high users responded but little generalisationSome lower users showed good response (‘super learners’)
44 Participants’ Attitudes Generally positive regarding model of service delivery, when combined with therapist support.Those with family members who could support use of computer were more positive.Many found the repetitive stimulation ‘boring’ & likely to be factor in low compliance in some participantsPositive responses from carers:“I felt I could leave him, knowing he had something useful to get on with.”“I got more gardening done that summer.”
45 Why impairment therapies sometimes don’t work (Varley, 2011. IntJSLP) Based on biologically implausible computational modelsLow dose.Focus on conscious, metalinguistic, declarative knowledge vs. Implicit/procedural knowledge.Insufficient practice of ‘getting it right’.Focus on isolated level (module/level of representation) & ignore interconnectedness of information processing & neural system.
46 Summary & ConclusionsIntervention study with larger sample of patients, administered single treatment protocol.Self-administered, IT-based therapy may represent cost-effective way of resolving dosage problem.Word-level therapy for AOS is effective.Effects most evident on treated word forms, with maintenance of therapy gains.Unlike microstructural therapies, evidence of generalisation to untreated words if phonetically similar.Sub-groups may provide insight into those individuals who benefit most from therapy
48 Macrostructural Therapy for AOS Macrostructural (whole word/utterance) therapies used in AOS e.g. Key word therapy (Square-Storer, 1989) & Melodic Intonation Therapy.Intervention study: whole words, self-administered computer therapy.Self-administered computer therapy allows users to deliver intervention at times/locations convenient to them & without therapist being present.Potential to achieve high dose therapy.Computers ideal for delivering repeated stimulation necessary to stimulation reorganisation of damaged neural system (Bhogal et al., 2003; Pulvermüller & Berthier, 2008; Varley, 2011).
50 Segments & Speech Control Segmental models built upon evidence of switch errors (Jeremy Hunt, the culture secretary).But these errors rare in novice users of speech production mechanism (appearing after 7 yrs Stemberger, 1989), & rare in acquired speech disorders (Varley & Whiteside, 2001).Influenced by word frequency, occurring on lower frequency words.
51 Background Assessments Screens for:Prognostic indicatorsSeverity of aphasiaAuditory processingDysarthriaNon-word repetitionPresence of oral apraxiaRepetition primingSeverity of AOSCloze/isolated productionHealth economic assessmentPsycholinguistic battery
52 Data Analysis (Cowell, et al. 2010. Frontiers in Human Neuroscience). Cross-over designs typical in drug trials.Small number in cog-behavioural interventions (e.g. Fillingham, 2005; Raymer et al, 2010).Avoids ‘resentful demoralisation’ of randomisation to sham in open-label RCT.But semi-permanence of successful cog-behav. therapy creates statistical problem: setting of new baselines across phases.Use of delta scores; lambda statistic to determine if possible to join 2 phases of trial.Accuracy score: Test 1 20/35; Test 2 30/35; delta =-10Word duration: Test 1 400ms; Test 2 300ms; delta = +100
Your consent to our cookies if you continue to use this website.