Motor speech disorders

Cranial nerves involved in motor speech

CNV (trigeminal): jaw movement, chewing, speech

CNVII (facial): facial expression and lip movement

CNIX (glossopharyngeal): pharyngeal movement

CNX (vagus): phonation and resonance through laryngeal and velopharyngeal control

CNXI (accessory): head and neck

CNXII (hypoglossal): tongue movement

parts of the brain involved in motor speech

• cerebrum: planning, initiating speech

• brainstem: swallowing; midbrain, pons, medulla

• cerebellum: coordinating smooth, well times and appropriately scaled movements

• neurons: transmit signals

Upper motor neurons (UMNs)

• originate in the motor cortex

• travel down through the brain and spinal cord

• initiate and modulate voluntary movement

Lower motor neurons (LMNs)

• begin in brainstem and spinal cord

• pathway to neurons in the muscles

Impacts for motor speech from lesions to the pyramidal system

• lesions above the brain stem result in symptoms on the contralateral side of the body

• lower half of the face and tongue receive contralateral cortical innervation only

• other muscles of speech production receive bilateral motor cortex input

extrapyrmadial system

multisynaptic pathways that connect motor areas of the cerebral cortex to the lower motor neuron

have pitstops via basal ganglia, substantia nigra, red nuclei, subthalamic nuclei

control hypokinetic and hyperkinetic movement

hypokinetic signs

lack of spontaneous movement

• akinesia: inability to complete a motor act, slowness in initiation and execution

• bradykinesia: delayed or false starts in the commencement of movement and slowness once the motor act is initiated

hyperkinetic signs

abnormal involuntary movements

unable to successfully inhibit cortical motor activity

disrupt the rate and rhythm of motor activity

dyskinesia

abnormal involuntary movements

myoclonus

involuntary single or repetitive fast jerking movement

tics

rapid compulsive movements that may be voluntarily suppressed

chorea

purposeless rapid random movement of body part

ballismus

gross abrupt muscular contractions causing flailing movements (stroke)

athetosis

slow purposeless writhing movements (CP)

dystonia

abnormal involuntary movement from simultaneous contraction of agonist and antagonist muscle

tremor

involuntary rhythmic movement of body part

definition of dysarthria, what is it associated with

speech disorders resulting from disturbances in the CNS and/or PNS that control the muscles of speech production

associated with slowness, weakness, incoordination of muscle movements

subsystems which may be affected in dysarthria

respiratory system

phonatory system

articulatory system

resonatory system

7 types of dysarthria

flaccid

spastic

ataxic

unilateral upper motor neuron

hypokinetic

hyperkinetic

mixed

Flaccid dysarthria (lesion, characteristics)

• lesion: lower motor neuron system, between brainstem and SC, cranial nerves

• loss of reflexive, automatic, voluntary control of muscles

• muscle weakness

• breathiness, short phrases, hypernasality, imprecise consonants, harshness, monopitch

unilateral upper motor neuron dysarthria (UUMN)

• lesion: upper motor neurons

• spasticity and incoordination

• unilateral lower facial weakness

• unilateral lingual weakness

• mild and transient speech difficulties

• imprecise consonant production

spastic dysarthria

• lesion: bilateral upper motor neuron damage

• slow effortful and strained speech

• imprecise consonants, distorted vowels and hypernasality

• low pitch, harsh voice, strained

• monopitch, monoloudness

• prosodic excess

ataxic dysarthria

• lesion: cerebellum and/or its connections

• coordination and timing deficits rather than weakness

• prosodic excess

• articulatory inaccuracy

• phonatory-prosodic insufficiency

hypokinetic dysarthria

• lesion: extrapyramidal system

• slowness or movement and/or lack of spontaneous movement

• prosodic insufficiency

hyperkinetic dysarthria

• lesion: extrapyramidal system (basal ganglia)

• chorea or dystonia isolated to the face and larynx

• slow, slurred and effortful speech

• laryngeal tremor or dystonia - shaky or tight voice that closes off when speaking

Huntington’s chorea

• common hyperkinetic disorder

• choreiform movements

• sudden, forced involuntary inspiration/expiration

• random hyperadduction of vocal folds and poor resonatory-phonatory control

• prosodic excess

• phontaroy stenosis (harsh, strained, vocal arrests)

• articulatory-resonatory incompetences

mixed dysarthria and clinical examples

• lesion: more than one level of the nervous system

• ALS, Multiple sclerosis, TBI

Motor speech programmer (MSP)

• a network of interacting structures and pathways that temporally sequences the motor movements necessary for accurate speech

apraxia

• have accessed the correct phonemes initially in the correct sequence

• have the peripheral physical capacity to say the word but cannot find the phonetic shape and/or transitions from sound to sound

Key features and characteristics of apraxia of speech

• articulation disturbances

• fluency disturbances

• rate & prosody disturbances

• task variables influence

articulation distortions in apraxia of speech

• consonant distortions predominate

• distorted anticipatory substitutions

• distorted perseverative substitutions

• distorted additions

• distorted sound prolongations

• distorted voicing distinguishments

rate & prosody disturbances in apraxia of speech

• slow overall rate

• prolonged but variable vowel duration in multisyllabic words/phrases

• prolonged interword intervals

• difficulty altering rate on command

• restricted altered pitch

• altered stress

• halting, effortful and irregular speech characteristics in apraxia

fluency disturbances in apraxia of speech

• multiple attempts to self-correct errors

• false articulatory starts and restarts

• groping for articulation postures

• sound & syllable repetitions

influential task variables in AOS

• error higher for volitional vs automatic utterances

• consonant cluster errors more frequent

• auditory-visual stimuli better than single mode

• speech sequential motion rates (SMRs) “pataka” harder than alternate motion rates (AMRs) “papapa”

intervention targets for aphasia, apraxia, dysarthia

aphasia: language comprehension and expression

apraxia: retraining motor sequences

dysarthria: strength, coordination and tone of muscles

neuroplasticity

the brain’s capacity to reorganise its structure and function in response to experience, learning and injury

Principles of experience-dependent neuroplasticity (8)

Use it or lose it

Use it and improve it

specificity

intensity matters

repetition matters

salience matters

Increase complexity

timing matters

principles of motor learning (practice conditions)

• intensity of sessions

• distribution of sessions

• variability of tasks

• schedule of tasks

• task complexity

principles of motor learning (feedback conditions)

• type of feedback: Knowledge of performance (KP) or Knowledge of results (KR)

• frequency of feedback

• timing of feedback

What is the effect of speech mechanism impairments and examples?

speech mechanism impairments leads to speech that sounds atypical

• speech mechanism impairments: reduced range of movement, reduced speed of muscles, VF hyperadduction, velopharyngeal incompetence

• atypical speech: slurred speech, imprecise consonant production, hypernasality, strained voice)

5 primary and overlapping approaches to the management of dysarthria

• medical

• behavioural

• prosthetic

• augmentative and alternative communication (AAC)

• counselling and support

Goals of treating flaccid dysarthria

• increasing strength and control of muscles

• compensating for weakness to improve intelligibility

interventions for flaccid dysarthria

• increasing respiratory support

• speech breathing practice

• abdominal diaphragmatic breathing

• breathing against resistance

• prosthetic assistance using expiratory boards or biofeedback tools

• articulation therapy to target specific sounds and increase articulatory/phonatory effort

• over articulation

• CPAP for velopharyngeal strengthening

goals for treating spastic dysarthria

• reduce spasticity and to reduce gradual appropximations of a full range of movements

Interventions for spastic dysarthria

• facilitate air flow by increasing respiratory support and coordination with speech

• reduce hyperadduction of VF using muscle relaxation techniques, forward focus, deconstruction exercise, vocal function exercises (sustained ‘eeee’)

• palatal lift

• CPAP

goals for treating ataxic dysarthria

• improving of compensating for deficits of motor control and coordination

intervention for ataxic dysarthria

• establish regular respiratory cycle and adding voice

• starting and stopping voice in one exhalation

• phonatory control

• contrastive intonation and stress drills

• improve consonant imprecision & vowel distortion (isolations)

goals for treating hyperkinetic dysarthria

• reduce excessive and/or abnormal involuntary movements

• surgical and pharmacological management most effective

• behavioural techniques: bite blocks, rate reduction strategies, postural adjustments

interventions for unilateral upper motor neuron dysarthria (UUMN)

• behavioural approaches that target articulation, rate and prosody

intervention for mixed dysarthria

• focusing on subsystems impacted and the nature of presenting impairments

2 examples of evidence-based neuroplasticity based intervention

LSVT

BeClear

summarise what is LSVT LOUD

• focuses on phonation

• concomitant improvement : articulation, rate, overall intelligibility

• intensive program -16 sessions

• max phonatory effort, high therapeutic effort, voice awareness and use

features of LVST LOUD

• Focus on voice

• Focus on high effort

• Focus on intensive treatment

• Focus on calibration

• Focus on quantification (documentation & measurements)

daily tasks in LSVT LOUD (3)

1. maximum duration sustained phonation

2. maximum fundamental frequency range

3. maximum functional speech loudness

hierarchical speech loudness tasks in LSVT LOUD

• structural reading and spontaneous speaking

• increasing in complexity with each week: words, simple phrases → sentences, simple conversation → reading/conversation → conversation

tasks in LSVT LOUD Merthods

• daily tasks (hierarchical by each week)

• homework tasks

• carryover assignments

Goals of BeClear Treatment: Clear speech training

• modifying habitual speech to enhance intelligibility

  • rate reduction

  • overarticulation

principles of neuroplasticity: Be Clear

• specificity: exclusive practice of connected speech tasks

• intensity: 1 hr treatment, 4x per week, for 4 weeks

• Salience: meaningful communication using individualised stimuli

• repetition: high level of repetition within and across treatment sessions

Components of the BeClear Treatment Protocol

1. Extended pre-practice: shaping and instatement, KP feedback & modelling by clinician

2. pre-practice: stimuli randomly selected, KP feedback & modelling

3. practice: functional phrases (everyday; out and about phrases) & functional speech tasks (reading, PDT, conversation); KR feedback

4. Home practice: functional phrases, reading aloud, PDT, conversation

6 guiding principles for management of apraxia of speech (AOS)

1. not all patients will be appropriate for treatment

2. counselling and education of patient and family regarding the nature of AOS and treatment rationale are important

3. repetition and drill are essential - 10 000 reps

4. tasks are hierarchical

5. self-monitoring is essential

6. salient treatment targets

Restorative approaches to AOS intervention

• to improve/restore impairments

  • articulatory-kinematic

  • sensory cueing

  • rate and rhythm control

  • intersystemic facilitation (using other intact motor system to support speech production)

compensatory approach to treating AOS

when not responsive to retraining

• AACL functional communication option AND supports

treatment stimuli for AOS

• to provide greatest benefit or foundation for improvement

• stimulability used but generalisation with complex untested targets

• words and phrases more motivating and functional

• meaningful, self-selected stimuli

• hierarchical

• patient-centred

DIfference between treatment for dysarthria vs apraxia

dysarthria: from underlying pathophysiology

• start at word level

• more collaborative

• keep moving on from errors

apraxia: from severity of speech production

• start at phoneme level

• more clinician-led

• do not accept errors

treatment selection for mild-moderate deficits vs severe deficits in AOS

mild-moderate

• target rate, melodic flow

• multisyllabic level

severe

• postural shaping and production of functional units

• sound-syllable-word level

Which treatment for AOS is considered most evidence based?

articulatory-kinematic approaches

articulatory kinematic approaches (what is articulatory, kinematic, goal and examples)

• articulatory: movement of the lips, jaw, tongue

• kinematic: timing, sequencing, speed and placement

• how the articulators move during speech

• goal is to retrain the brain to plan and execute speech movement more accurately

• e.g. eight-step continuum, sound production treatment (SPT), PROMPT, rate/rhythm approaches

articulatory-kinematic approach: eight step continuum

• WATCH, LISTEN, DO

• progress from phoneme repetition to independent utterance

• maximum support (1-2), fading cues (3-5), independent (6-8)

articulatory-kinematic approach for AOS: sound production treatment (SPT)

• combine eight-step continuum with articulatory placement cueing, phonetic tasks and extensive modelling

• if unable to produce: provide phonemic cards, verbal, visual or tactile cues

Sound production treatment (SPT) for Severe AOS treatment: 3 phases

Phase 1: Sound production - sustained phonation of /ah/ and variations

Phase 2: rehearse automatic responses to experience fluent speech production

Phase 3: phonemic drill and return to volitional speech

Articulatory-kinematic intervention for AOS: PROMPT (Prompts for reshaping oral muscular targets)

• tactile cues

• when patient produces incorrect production of phonemes, SLP will find the correct contact points for relevant phonemes and move the articulators passively. Then the patient will repeat the attempt with SLP moving articulators simultaneously

Articulatory-kinematic intervention for AOS: Rate/rhythm approaches

• slowing speech rate using paced or metred speech

• incorporating intonation, stress, rhythm cues

• Melodic intonation therapy (MIT): incorporating singing

• Contrastive stress drills