Acquired Apraxia of Speech: SF Lectures 2024 PDF

ACQUIRED APRAXIA OF SPEECH: NATURE AND ASSESSMENT SENIOR FRESHMAN 2024 JESSICA MOLLOY CLINICAL SPECIALIST SPEECH AND LANGUAGE THERAPIST, ST JAMES’ HOSPITAL, DUBLIN [email protected] LECTURE OUTLINE  Assessment of AOS  Introduction...

ACQUIRED APRAXIA OF SPEECH: NATURE AND ASSESSMENT SENIOR FRESHMAN 2024 JESSICA MOLLOY CLINICAL SPECIALIST SPEECH AND LANGUAGE THERAPIST, ST JAMES’ HOSPITAL, DUBLIN [email protected] LECTURE OUTLINE  Assessment of AOS  Introduction  Principles of assessment  Nature of Apraxia of Speech (AOS):  Case history  Definition of AOS  Oro-motor assessment  History of AOS  Speech tasks  Presentation of AOS  Features  Formal assessments  Severity  Functional assessments  Overlap with other communication disorders  Differential diagnosis  Etiology and neurobiology of AOS  Theories and models of AOS  Reading list and references  Non-discriminatory features of AOS JESSICA MOLLOY 2020 INTRODUCTION: LIVING WITH APRAXIA OF SPEECH I could say one I can’t even word just fine, remember… what it …what happens is I know then still say it was like to talk without what I want to say, but again five really having to think my mouth can’t make minutes later about certain things the sound fast enough and it’s messed up I can now say Sometimes I can make all of the it through an entire sounds… so sentence and have it be now I start to just fine, but then I get work on to a word that has a lot making myself of syllables… sound more JESSICA MOLLOY 2020 like me Haley et al., 2016, p. S693 DEFINITION OF APRAXIA OF SPEECH (AOS)  “AoS is broadly defined as an acquired disorder of learned volitional actions associated with breakdown in the planning or programming of the movements needed for speech” (Miller and Wambaugh, 2017, p. 493). JESSICA MOLLOY 2020 Sometimes called “verbal apraxia” or “dyspraxia” in the literature but AOS is the preferred terminology DEFINITION IN MORE DETAIL AOS: AOS:  Is acquired  Is not developmental – like “childhood apraxia of speech” or “developmental verbal dyspraxia”  Does not affect reflexive movements, e.g.  Affects volitional movements coughing  Does not affect non-speech movements e.g. smiling, blowing – if these are affected this is  Affects movements for speech known as “oral apraxia” or “bucco-facial apraxia”  Breakdown is not in expressive or receptive  Breakdown is in planning or language (aphasia) or oro-motor strength or programming movements needed for sensation (dysarthria) speech JESSICA MOLLOY 2020 HISTORY OF APRAXIA  The term “apraxia” was initially used to describe problems moving limbs, i.e. arms and legs.  Liepmann (1900a) described a patient who was unable carry out movements, in the absence of any paralysis (weakness) or ataxia (incoordination).  This led Liepmann to develop an influential theory about how our brain sends instructions to our limbs to carry out movements. When this process is disrupted – the result is an “apraxia”.  This disorder known as “apraxia” can affect limb movements (as described above); eye movements (“ocular apraxia”); facial movements (“oral/bucco-facial apraxia”, or it can affect the ability to carry out movements using objects- known as “ideational apraxia”. JESSICA MOLLOY 2020 “STORMY” HISTORY OF APRAXIA OF SPEECH (DUFFY, 2013: P. 270) Darley (1969): described a Further patient “Linda” Wertz et al. changes to who presented Challenged by criteria criteria in with an many authors formalised by 2006 articulatory and debated Dabul (1986) (Wambaugh disorder he for many in the Apraxia et al.) and called “apraxia years – does Battery for 2015 (Ballard of speech” it even exist? Adults (ABA) et al.) Disordered ability New definition AOS redefined to program and and by McNeil et sequence the diagnostic al. (1997): movements for features kernel volitional speech proposed by features production, without Wertz et al. which could deficits in speed, (1984) differentially strength, diagnose AOS coordination from aphasia JESSICA MOLLOY 2020 (Johns and Darley, 1970) FEATURES OF AOS CORE SPEECH SYMPTOMS FOR AOS DIAGNOSIS JESSICA MOLLOY 2020 CURRENT DIAGNOSTIC CRITERIA FOR AOS Kernel features of AOS Sound distortions/substitutions “Substitutions” = speaker has selected or accessed Diagnosis of AoS is based on a “perceptually derived incorrect phonemes and articulated these normally cluster of behaviours” (McNeil et al., 2017, p. 201) (e.g in phonemic paraphasia) “Distortions” = correct phoneme was accessed, but “Kernel features” (McNeil et al., 1997; 2004; 2009) articulated in an imprecise or unusual way (e.g. in Sound distortions (including distorted substitutions) AOS, dysarthria) Extended segment* durations “Distorted substitutions” = the impression that both Extended intersegment durations phoneme selection and articulatory accuracy are Prosodic deficits incorrect – most common error type in AOS Most common distortions in AOS: length, voicing, tongue placement JESSICA MOLLOY 2020  Other features may also be seen in AOS but shouldn’t be used to “KERNEL” FEATURES OF AOS discriminate between AOS and other disorders Extended (inter)segment durations Prosodic deficits “Extended segment durations” = lengthened  May see restricted alteration of pitch, production of consonants and vowels  rate intonation, loudness – may sound monotonous of speech is perceived as slower overall  Slow rate of speech is common – this may be due to increased segment and intersegment “Extended intersegment durations” = durations lengthened pauses between sounds and  Equal lexical stress between words  speech sounds segmented  Individuals with AOS are highly likely to May also be referred to as “syllabification” produce more equal lexical stress (i.e., over- May insert “intrusive schwa” in between segments stress the initial weak syllable) in multi- syllabic words (Ballard et al., 2016)  No longer sound like themselves/unnatural JESSICA MOLLOY 2020 *Segment = smallest unit of sound sounding e.g. a consonant or syllable  Can very occasionally sound like a foreign FEATURES OF AOS  Discriminatory “kernel” features ? Non- discriminatory features  Sound distortions/distorted substitutions ? Articulatory groping  Extended segment durations ( realised as  ? Perseverative errors slow rate) ? Increasing errors with word length  Extended intersegment durations (realised ? Speech initiation difficulties as  syllabification) ? Awareness of errors  Prosodic deficits ? Automatic speech > propositional ? Islands of error free speech  Not a feature of JESSICA MOLLOY 2020 AOS SEVERITY OF AOS  You may encounter different presentations of AOS in the clinic depending on which combination of these symptoms are present together, and how severe each of the symptoms are.  This results in a wide scale of AOS severity from those who have mild difficulty speaking in conversation, to those who cannot say single words. slightly slow segmented slow, speech with lots of complete relatively sound errors and inability to fluent disturbed prosody speak speech JESSICA MOLLOY 2020 SEVERE AOS – MINIMAL OR NO SPEECH OUTPUT  In some cases, the difficulty planning or programming the movements for speech is so severe that it is hard for the person to produce any speech sounds, in any context (reading, repeating/imitating, spontaneous speech)  These clients may sometimes be described as “non-verbal”  In other severe cases, a client might be able to produce one or two speech sounds or syllables, (usually when imitating the SLT) but have difficulty stringing syllables together to make words It is difficult to reliably diagnose AOS in a client who has very little speech output, because this does not allow you to observe the core features of AOS. You might reach a tentative diagnosis of “probable” or “suspected” AOS but you may also need to consider other diagnoses such as aphasia. Being unable to produce any verbal output can also be caused by aphasia. JESSICA MOLLOY 2020 OVERLAP WITH OTHER COMMUNICATION DISORDERS  AOS almost always co-occurs with aphasia ? in over 90% of cases AOS  It sometimes co-occurs with dysarthria  This makes assessment and diagnosis more tricky  Cases of pure AOS are rare; only a handful Dysarthri have been described Aphasia a  Researchers continue to look for pure cases as they are helpful for understanding the disorder, but you are unlikely to come across many in practice… JESSICA MOLLOY 2020 ETIOLOGY OF AOS  Acute AOS:  Primarily caused by stroke – typically left hemisphere; most often frontal and parietal lobes; most often larger strokes  Can also be caused by head injury (traumatic brain injury or TBI) or a brain tumour/brain surgery  Primary progressive AOS (Josephs et al., 2006):  Isolated progressive motor speech deficit can be the first sign of a progressive neuro- degenerative disease, such as: Cortico-basilar degeneration (CBD); Progressive supranuclear palsy (PSP); Motor neurone disease (MND)/Amyotrophic lateral sclerosis (ALS) JESSICA MOLLOY 2020 NEUROBIOLOGY OF AOS  Pinpointing a singular brain region associated with AOS has been controversial, with many different lesion sites proposed, including: the left insula; Broca’s area/left inferior frontal gyrus; the pre-central gyrus and post-central gyrus i.e. primary motor and somatosensory areas) and the pre-motor cortex (Basilakos et al., 2015; Graff-Radford et al., 2014)  Why is it hard to say where AOS lesions occur?  Our current understanding is that speech is likely organised across a wide network of structures with different roles including: parts of Broca’s area, precentral gyrus, postcentral gyrus, anterior insula, subcortical structures (basal ganglia, cerebellum)  Stroke/TBI can affect multiple areas of the brain  The organisation of speech in the brain may change after stroke/TBI due to neuroplasticity and cortical reorganisation therefore we don’t know whether different structures have taken over different roles in the person with AOS  Moser (2016) reported on 2 people with similar cases of AOS who had very different brain damage locations when brain imaging (MRI scan) was used suggesting there may not be one area specific to AOS  Research studies have often used differing diagnostic criteria to identify AOS (due to the controversies about diagnostic symptoms) and this makes it hard to compare and collate results of different experiments JESSICA MOLLOY 2020 MODELS AND THEORIES OF AOS AOS is a breakdown in motor planning  There are two dominant theories: How does motor  Van der Merwe 4-stage model planning  DIVA/GODIVA model work? What goes wrong with motor planning in AOS? JESSICA MOLLOY 2020 WHAT’S IN A MOTOR PLAN OR PROGRAMME? Teeth Tongu e Lips Alveol Articulator When Palate s ar ? ridge How fast? What? With how much force? /p/ /b/ 18 VAN DER MERWE (1997) Conceptual- Motor Planning Motor Programming Linguistic Strategy of action Muscle-specific Pre-motor stage Spatial specifications programs selected Intention to speak (place and manner) and sequenced Execution Message Temporal Spatial and temporal constructed: syntax, specifications dimensions: tone, semantics, (timing) direction, force, rate morphology   Core motor plans Phonological plan = goals of (phonemes) movement Dysarth Aphas ria AOS JESSICA MOLLOY 2020 ia WHAT GOES WRONG WITH MOTOR PLANNING IN AOS? We don’t know for definite yet and researchers continue to try to answer this question. There are several possible ways in which motor planning/programming can possibly go wrong after a stroke/TBI which might explain the types of the errors we see in AOS: ? The brain mis-selects the incorrect motor programme (i.e. the opening or closing settings or sequences for the articulators) for the intended production target (e.g. selects the programme for /p/ when the target was /d/) ? The brain can no longer access stored programmes for the intended target, or the quality of these stored programmes has deteriorated ? There is interference in the brain between competing motor programmes (e.g., competition between the tongue tip vs. dorsum raising in target /’take’/  dorsum raising “wins”  may lead to what the listener hears as /‘cake’/ ? The correct programme is selected, but the programme is applied to the wrong articulator (e.g., closing gesture applied to tongue dorsum instead of lips for the target /m/ would result in production of /ng/ instead) We also still don’t know what size these programmes in the “speech sound map” are – sound/syllable/word/phrase? (Ziegler, et al., 2012) JESSICA MOLLOY 2020 (Miller and Wambaugh, 2017 – see p. 504 re: “derailments to motor DIRECTIONS INTO VELOCITIES OF ARTICULATOR (DIVA) MODEL http://sites.bu.edu/guentherlab/research-projects/the-diva-model-of-speech-mot or-control/  This model suggests that we have a “speech sound map” believed to be located in the left frontal cortex  This “map” area is believed to be made up of “mirror neurons” (Hickock, 2012) which are activated both when a sound is produced and heard  These neurons in this area are thought to be responsible for motor planning/programming by sending out “feedforward” commands to the articulators, and receiving “feedback” from auditory and sensory routes  Researchers have tested this theory with speech- generating computer software – when they disable this “map” area in the computer model- the result is speech that replicates AOS i.e. sound distortions, JESSICA MOLLOY 2020 prosodic disturbance (Guenther, 2006) FEEDFORWARD & FEEDBACK IN MOTOR PLANNING / 1. A movement goal is identified (e.g. producing ahai/ syllable) 2. A motor program or command for that movement is activated and initiated Feed forwar 3. Simultaneously an efference copy of that command is generated, i.e. a prediction of the d expected sensory feedback from the issued motor command Is this 4. As the movement unfolds, the actual sensory consequences are compared to right? the prediction 5. If a mismatch is detected, error signals arise and corrective motor commands are Feed generated to modify the ongoing movement back 6. The error signals are also used to update the “stored” motor programs, thereby improving the accuracy of future attempts to perform that motor task  this is motor learning JESSICA MOLLOY 2020 (Ballard, Tourville and Robin, 2014) OTHER FEATURES OF AOS NON-DISCRIMINATORY FEATURES JESSICA MOLLOY 2020 NON-DISCRIMINATORY FEATURES These signs are often seen in AOS but are not considered core or “kernel” features of the disorder  Groping, effortful speech, difficulty initiating speech  Awareness of errors and self-correction  Variability of errors  Increasing errors with word length  Automatic speech better than propositional speech e.g. counting 1-10 easier than counting 10-1  Islands of error free speech  These can also be seen in aphasia; they are not unique to AOS and therefore not reliable for diagnosis of AOS on their own. JESSICA MOLLOY 2020 GROPING/EFFORTFUL SPEECH/DIFFICULTY INITIATING SPEECH  “Articulatory groping” frequently occurs in AOS  Gives the impression that the speaker searches for articulatory postures, recognizes inaccurate postures, and attempts to self-correct  Groping may be audible, or silent but visible  It is not a discriminatory sign for AOS as it also occurs in aphasia  Effortful speech, difficulty initiating speech, dysfluent speech also often described in both AOS and aphasia  “Effort” of speaking is difficult to define but may be self-reported as a symptom (see Jennifer Shafer’s reports in Haley et al 2016) “I can’t even remember at this point what it was like to talk without JESSICA MOLLOY 2020 having really to think about certain things.” AWARENESS OF ERRORS AND SELF-CORRECTION  Awareness of errors in own speech was historically considered a clinical feature of AOS in original early definitions  This is not well supported by recent studies:  PWAOS vary greatly in their ability to judge their errors (Deal & Darley, 1975; Wambaugh et al., 2016; Mauszycki et al., 2017)  PWAOS under-predict how many errors they will make on single words (Marquardt et al., 2010)  PWAOS are likely to judge their productions overly positively (Wambaugh et al., 2016)  Error awareness and ability to self-correct is thought to be important for therapy however studies have not yet proven that (Wambaugh et al., 2017)  It can also be argued that too much self-correction can result in reduced fluency of speech which may negatively affect listener perception JESSICA MOLLOY 2020 ERROR VARIABILITY: A MATTER OF CONTROVERSY error location: error type: whether the Dog  Dog  whether an error same error is made dod dok occurs on the same within the same Dog  Dog  target sound within location of a word dok dok a word across across repeated trials Dog  Dog  repeated trials doj  Historically, AOS was considered to be characterised by highly variable errors (Johns dok and Darley, 1970)  Diagnostic criteria for AOS were later changed to include: “relatively consistent errors in error location and type” (McNeil et al., 2004; Wambaugh et al., 2006)  More recent findings do not support relative error consistency, or inconsistency, as effective criteria in the differential diagnosis of AOS and aphasia (Haley et al., 2013; Bislick et al., 2017 for detailed discussions)  Duffy (2013) suggested that individuals with AOS with more severe impairment demonstrate more consistent and predictable errors compared with those with milder deficits due to their more limited sound repertoire JESSICA MOLLOY 2020 INCREASING ERRORS WITH INCREASING WORD LENGTH  AOS presence has recently been shown to be strongly associated with increased errors on words of increasing length (Ballard, 2016)  Emerging research is suggesting that this speech feature may be useful for distinguishing between aphasia and AOS but more evidence is required  Multisyllabic words require motor planning of several phoneme and syllable units at a time, as well as variations in relative duration and amplitude of movements across adjacent units to achieve the correct stress contrast  they require significantly increased motor programming and thus are likely more challenging for people with AOS JESSICA MOLLOY 2020 ASSESSMENT OF AOS PRINCIPLES AND PRACTICE JESSICA MOLLOY 2020 PRINCIPLES OF ASSESSMENT  Remember you are assessing for treatment planning, not for the sake of assessment  your goal is to obtain information that will help you to plan a therapy approach (Ballard et al., 2002).  Assessment of AOS relies largely on perceptual assessment i.e. listener (SLT) judgment of speech in single words and connected speech tasks. There is still some debate about whether this method is reliable, and there is ongoing research into whether SLTs or other listeners can consistently agree, or reach the same judgement, after listening to a speech sample (Mumby et al., 2007). However it is currently the best tool we have for diagnosis of AOS.  Other methods of assessment which have been used in research include acoustic and physiological methods, but these are often not accessible or practical in the clinic (see McNeil et al., 2016, pp. 205- 208; and Duffy, 2013 for discussion of these methods). JESSICA MOLLOY 2020 1. CASE HISTORY What do you need to find out ? How will you find all of this out?  Baseline speech – developmental stutter; pre-existing aphasia, dysarthria; inter-dentalisation  Baseline literacy – important for assessment and therapy Patie Famil  Native language nt y  Lesion location; left hemisphere associated with AOS (see slide 14)  Hearing? Vision (pre- and post-lesion)? Medi  Other neuro issues post-lesion: Hemiparesis? Limb apraxia? Ideomotor apraxia? cal MDT JESSICA MOLLOY 2020  Social history: family, occupation, roles, interests, chart personality 2. ORO-FACIAL EXAMINATION  Apraxia of speech may be present in the absence of any oro-motor weakness, incoordination or altered sensation.  There may be inability to imitate or follow commands to perform non-speech volitional movements of speech structures (Duffy, 2013) – the client can often perform the same movement reflexively  This is known as non-verbal oral apraxia (NVOA) - also called “bucco-facial apraxia”  While AOS and NVOA frequently co-occur (in at least 40% of PWAOS) – there is also evidence that they can dissociate i.e. a person can have AOS without NVOA, and vice versa  NB: presence of NVOA does not imply person has AOS  We do not know if speech and non-speech movements are localised to the same part of the brain…this has implications for using non-speech movements in therapy JESSICA MOLLOY 2020 (see Duffy, 2013 for detailed discussion re: oro-facial examination in AOS and 3. DDK RATE  Assessment of diadochokinesis = ability to make antagonistic movements in quick succession  Alternating Motion Rates (AMRs): "/ppppp//ttttt//kkkkk/  Sequential Motion Rates (SMRs) : /ptk/ptk/ptk/ptk/  Observe for:  Accuracy of articulation, speed and correct sequencing  SMRs will typically be worse than AMRs in AOS because they require increased motor planning JESSICA MOLLOY 2020 4. PERCEPTUAL SPEECH TASKS  Automatic speech tasks (e.g. counting 1-10, days of the week)  Repetition/imitation of:  monosyllabic words  multisyllabic words  words of increasing length (see slide 27)  sentences  Elicit multiple repetitions of each word to assess variability – see slide 26  Narrative/discourse sample (e.g. picture description task)  Reading aloud JESSICA MOLLOY 2020 See Duffy (2013) for speech tasks/screening tool LOOK FOR PATTERNS OF ERRORS  Transcription: what types of errors are occurring? Distortions? Substitutions? Distorted substitutions?  Is the rate of speech normal? Slow? Are there extended (inter)segment durations? Volitional and  Prosody: Is the intonation pattern typical? Is there equal stress? propositional speech tasks require more  Compare automatic vs. volitional speech motor planning and  e.g. count from 1-5 versus count from 5-1, days of the week backwards are likely to be more difficult than  Which do you expect will be hardest/easiest for person with AOS? automatic tasks or  Compare repetition vs. propositional speech vs. reading repetition/reading  Which do you expect will be hardest/easiest for person with AOS?  Ask the client to speak at a faster rate– is this when errors appear? Inability to maintain accuracy with increased rate is often suggestive of AOS JESSICA MOLLOY 2020 OTHER ASSESSMENTS  Assess overall speech intelligibility – this is often a useful outcome measure to complete pre- and post-therapy  Ask the client to provide a self-rating of their speech or of the effort required to speak  May need to provide visual supports, e.g. visual analog scale, numberline from 1-10  Expressive and receptive language assessments should be completed if indicated  Is there aphasia present- what type? How severe is it?  Cognitive assessments/non-verbal reasoning – liaise with OT, Psychology and medical colleagues  Written language assessment – establishing written language ability is important if AAC is needed to supplement verbal output Consider  Can the person understand written words? Can they write? vision and limb JESSICA MOLLOY 2020 function ASSESSING SEVERITY  There is no standard method of assessing severity of AOS  Severity is typically rated subjectively by clinicians based on judgement of speech  When rating severity, you may consider factors like intelligibility test scores, frequency of errors in speech, percentage of sounds correct in a sample, subjective degree of effort of speaking JESSICA MOLLOY 2020 APRAXIA OF SPEECH RATING SCALE (ASRS)  The ASRS: recently published tool designed for description and quantification of characteristics indicative of AOS  5-point scale which describes presence or absence of particular speech characteristics, and their severity  16 items organized according to whether they:  are considered to be discriminative of AOS;  can be apparent in patients with AOS but may also be exhibited by patients with aphasia  can be apparent in AOS but may also be seen in patients with dysarthria  can be apparent in AOS but may also be present in aphasia or dysarthria  Should be scored during and/or after listening to the individual’s speech during conversational speech, picture description, word and sentence repetition and speech-like AMR and SMR tasks  NB: Currently only standardised on people with progressive AOS, not stroke-related AOS (underway) JESSICA MOLLOY 2020 (Strand et al., 2014) JESSICA MOLLOY 2020 FORMAL ASSESSMENTS  Apraxia Battery for Adults (ABA) (Dabul, 1986, 2000)  Uses a range of tasks to elicit speech features considered characteristic of AOS… BUT based on diagnostic criteria which were developed in1980s  Updated diagnostic criteria have been published since, which have undermined the usefulness of this as a reliable way of diagnosing AOS, however it contains useful tasks and stimuli for assessment  See further discussion in McNeil et al., 2004, p. 394.  You can adapt formal assessments from other fields depending on what aspect of speech you want/need to assess  e.g. Assessment of Intelligibility of Dysarthric Speech (AIDS, Yorkston and Beukelman, 1981) JESSICA MOLLOY 2020 ASSESSING BEYOND IMPAIRMENT Tools for measuring activity and  Look beyond impairment level only participation, quality of life:  What is the impact of AOS on the person’s  Dysarthria Impact Profile (DIP) (Walshe, activities and participation? 2009)  What is the impact on their quality of life?  Visual Analogue Self-Esteem Scale (VASES) (Brumfitt and Sheeran, 1999)  LaTrobe Communication Questionnaire (Douglas et al., 2000) International Classification of Functioning, Disability and Health JESSICA MOLLOY 2020 (WHO, 2001) DIFFERENTIAL DIAGNOSIS OF AOS, APHASIA, DYSARTHRIA JESSICA MOLLOY 2020 DIFFERENTIAL DIAGNOSIS OF APHASIA AND DYSARTHRIA AOS vs. dysarthria AOS vs. aphasia  Errors in dysarthria tend to be more predictable than  Significant overlap with phonological errors in AOS (typically the same error on the same aphasia, with many common features sound e.g. /p/  /b/ on every production of /p/)  There is little variation with task in dysarthria i.e.  Sound distortions are present in both but similar error profile on reading, spontaneous speech, much more frequent in AOS than aphasia repetition whereas in AOS some tasks will be easier/harder with more/less errors  Prosody typically not affected in aphasia  More likely to see oro-motor deficits in dysarthria but core feature of AOS (which match to speech errors – e.g. lip weakness  See McNeil et al. (2004, p. 399 table) and resulting in difficulty with plosives, tongue weakness affecting lingual sounds) Miller and Wambaugh (2017, p. 501 table) JESSICA MOLLOY 2020 RECAP  Acquired, neurogenic disorder of motor planning and programming of volitional movements for speech  Ranges in severity from inability to speak to mildly imprecise or unnatural sounding speech  Results from a variety of usually left hemisphere lesions  Frequently co-occurs with aphasia and less frequently with dysarthria  Debate continues about how best to assess and differentially diagnose this condition but perceptual identification of a cluster of features is currently best practice  Assessment should consider performance on a battery of speech tasks, as well as examining the functional and psychosocial impact of disordered speech JESSICA MOLLOY 2020 KEY READING/CORE TEXTS  Duffy, J. R. (2013). Examination of Motor Speech Disorders. In Motor Speech Disorders: Substrates, Differential Diagnosis, and Management (pp. 61-93). St Louis, MO: Elsevier Mosby.  Duffy, J. R. (2013). Apraxia of Speech. In Motor Speech Disorders: Substrates, Differential Diagnosis, and Management (pp. 269–292). St Louis, MO: Elsevier Mosby.  Haley, K. L., Shafer, J. N., Harmon, Tyson, G., & Jacks, A. (2016). Recovering with acquired apraxia of speech: the first two years. American Journal of Speech-Language Pathology, 25(November), 1–15. https://doi.org/10.1044/2016  McNeil, M. R., Ballard, K. J., Duffy, J. R., & Wambaugh, J. (2016). Apraxia of Speech Theory, Assessment, Differential Diagnosis, and Treatment: Past, Present, and Future. In P. Van Lieshout, B. Maasen, & H. Terband (Eds.), Speech Motor Control in Normal and Disordered Speech: Future Developments in Theory and Methodology (2nd ed., pp. 195–222).  Miller, N., & Wambaugh, J. L. (2017). Acquired Apraxia of Speech. In I. Papathanasiou & P. 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