Treating Motor Speech Disorders: A Model-Driven Approach
Heather M. Clark, Ph.D. CCC/SLP
Foundations of Approach
 Address impairment, activity, and participation
 Impairment level treatment is based on sound neurophysiological principles
 Activity level treatment is based on principles of motor learning
 Participation level measurement and/or treatment is incorporated throughout management to validate benefits
Key Issue: Assessment
 Effective treatment depends on accurate assessment
 Identification of underlying impairments
 Strength
 Tone
 Range
 Coordination
 Differential diagnosis
 Dysarthria (type), AOS, Aphasia
Designing an intervention plan
 Functional goals
 Activity level targets
 Participation level targets
 Behavioral objectives
 Impairment level targets
 Activity level targets
Impairment Level Targets
 Tone
 Strength
 Range
 Coordination (best addressed at activity level)
Strength Training: A principled approach
 Issues to consider
 Does underlying weakness contribute to speech (and swallowing) problems?
 Can strength be improved by training?
 Will increased strength result in improved function?
Physiology review: Motor Units
 Motor unit: motoneuron and the muscle fibers it innervates
 Specific motor units are recruited for any given movement
 Force
 Speed
 Direction
Principles of strength training
 Goals
 Strength
 Endurance
 Power
 Overload
 Hypertrophy of muscle tissue
 Increased motor unit recruitment
Specificity of training
 The effects of strength training are highly specific to the trained behaviors
 This is primarily related to motor learning and motor unit recruitment
Factors subject to specificity
 Force
 Contraction velocity
 Duration
 Dynamics
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 Direction of load
 Kinematic chain
Force
 Low force: Type I units
 High force: Type II units
 If exercise is completed to the point of fatigue, both Type I & II are trained
Contraction velocity
 Power increased by
 Increasing resistance while maintaining contraction velocity
 Increasing velocity while maintaining resistance
 Combination of above
 Exercises should closely match speed of desired outcome
Dynamics
 Isotonic: muscle changes length while maintaining tension
 Isometric: muscle changes tension while maintaining constant length
 (principles apply to length of muscle, hence “range”)
Direction of Load
 Concentric: Resistance applied as muscle shortens
 Eccentric: Resistance applied as muscle lengthens
Kinematic Chain
 Open: distal segment moves freely
 Closed: body moves around fixed distal segment
Other issues
 Frequency: amount of time allowed for recovery between training sessions
 Progression: systematic increase of resistance, contraction velocity, and/or duration
Contra-indications for strength training
 Hypertonia
 Fatigue Susceptibility
 Absence of weakness
Issues
 Key descriptors in the oral system
 Direction of movement
 Force
 Speed
 Integration?
 Recovery
 No data are available regarding the optimal frequency of training sessions for oral-pharyngeal musculature
 Progression
 Increase resistance
 Increase repetitions or duration
 Increase contraction velocity
Strength-training as intervention
 Clearly identify treatment target
 Strength, endurance, power
 Direction, duration, and range
 Match exercise as closely as possible to desired movement outcome
 Be mindful of overload and progression
 Be mindful of contra-indications
Other Impairment-level Targets
 Tone
 Range
Tone
 Hypertonicity
 Goal is to decrease tone
 Inhibit stretch reflex
 Hypotonicity
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Goal is to increase tone
 Facilitate stretch reflex
Oral Motor Tasks Designed to Influence Tone or Range
 Slow stretch
 Fast stretch
 Massage
 Heat
 Cold
 Vibration
 Electrical Stimulation
Slow stretch

Description
 May be active, passive, or assisted
 Movements are slow and beyond typical ROM

Physiologic impact
 May inhibit stretch reflexes
 Loosens connective tissue and adhesions

Indications
 Generally employed to reduce spasticity

Contra-indications and cautions
 May not have same effects in orofacial system
 Inappropriate stretching can cause discomfort and swelling

Support: none
Fast stretch

Description
 Usually passive
 Movements are quick and non-sustained

Physiologic impact
 Intended to elicit stretch reflex

Indications
 Generally employed to increase tone

Contra-indications and cautions
 May not have same effects in orofacial system
 Inappropriate stretching can cause discomfort and swelling

Support: none
Massage

Description
 Stroking and/or application of pressure
 Effleurage, petrissage, friction, tapotement

Physiologic impact
 Loosens connective tissue adhesions, facilitate blood & lymph flow
 Central and peripheral relaxation
 Stimulate muscle spindles

Indications
 Generally employed to reduce spasticity (deep friction), increase tone (tapping), or improve ROM related to
scar tissue

Contra-indications
 May not have same effects in orofacial system
 Should not be employed without thorough understanding of tissue morphology

Support: Sullivan et al (1997) reported improved phonatory function
Heat

Description
 Heat applied to tissue
 May be deep or superficial

Physiologic impact
 Increases pain threshold

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Increases blood flow

Indications
 Generally employed to reduce pain associated with ROM

Contra-indications and cautions
 Should not be used on inflamed tissue
 Should not be used on patients with reduced ability to report pain

Support: none (TMJ?)
Cold

Description
 Application of cold to superficial tissues

Physiologic impact
 May reduce spasticity by decreasing conduction velocities
 Increases blood flow

Indications
 Generally employed to reduce spasticity

Contra-indications and cautions
 Should not be used on patients with reduced ability to report pain or discomfort

Support: none

Note: thermal stimulation affects sensation, not movement
Vibration

Description
 Low or high frequency vibratory stimulation

Physiologic impact
 TVR: stimulates muscle spindle; facilitates agonist & inhibits antagonist

Indications
 May be used to increase or decrease tone

Contra-indications and cautions
 May not have same effects in orofacial system
 Produces heat
 May damage skin, particularly around the face
 Should not be used in cerebellar or extrapyramidal lesions

Support: none
Electrical stimulation

Description
 Low voltage electrical currents applied to muscle fibers

Physiologic impact
 Causes contractions of muscle fibers

Indications
 Generally employed to improve strength and tone

Contra-indications and cautions
 May not have same effects in orofacial system
 Recruits MU in different order than volitional contractions; limits motor learning

Support: Swallowing: Park et al (1997); Freed et al (2001)
Impairment Level Targets
 Increase tone
 Strength training
 Fast stretch*
 Brief cold*
 Electrical stimulation
 Vibration to agonist*

*may not have same effects in oral system
 Decrease tone



Slow stretch*
Sustained cold*
Vibration to antagonist*
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 Increase ROM
Active or passive ROM / stretch
Heat
Specific Examples by Subsystem
 Respiration
 relaxation or posture adjustment to reduce tone
 Phonation
 laryngeal adduction exercises addressing vocal cord paralysis
 Laryngeal massage addressing spasticity and/or spastic dysphonia
 Resonation
 CPAP to train velar elevators
 Articulation
 Tongue strengthening to improve articulation
 Lip stretch to improve ROM
Activity Level Targets: Speech
 Disorders
 Dysarthria
 Apraxia
 Articulation, Voice, Fluency
 Any intervention focusing on improving integrated movement patterns during speech
Specific Examples by Subsystem
 Respiration
 Adequate use of available breath support
 Improved phrase grouping
 Phonation
 Easy onset phonation during connected speech
 Effortful phonation
 Resonation
 Appropriate oral/nasal resonance
 Articulation
 Exaggerated articulation of consonants and vowels during speech
 Intelligibility
 Prosody
 Slowed rate
Principles of Motor Learning
 Applies to any change in movement behavior related to changes in central motor unit recruitment
 Relevant to the learning of any skilled movement
Some definitions
 Acquisition
 Practice (therapy)
 When recruitment patterns are being established
 Specificity can be exploited
 Learning
 The game (retention and transfer)
 Recruitment patterns are being refined and generalized
 Specificity should be overcome
In general…
 Variables that exploit specificity facilitate acquisition but deter learning
 Variables that confound specificity prolong acquisition but result in better learning
Why?
 Recall and evaluation strategies play a role in motor learning
 Schema theory (Schmidt, 1998)
 Getting practice “recalling” movements and “evaluating” movements improves ultimate retention and transfer
Variables impacting motor learning
 Pre-practice variables
 Practice conditions
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 Feedback
Pre-practice variables
 Motivation
 Elicitation
 Instructions
 Models
Practice conditions
 Scheduling
 Massed vs distributed practice
 Variability
 Constant vs variable
 Target, context, etc
Feedback
 Type
 Knowledge of results (KR)
 Information about outcome
 Critical for learning
 Knowledge of performance (KP)
 Information about movement execution
 Most important to guide acquisition
 Temporal Locus
 Pre KR interval
 Post KR interval
 Frequency
 High frequency speeds acquisition
 Low frequency promotes learning
Motor Learning in Intervention
 Acquisition: Exploit specificity
 Blocked practice
 Consistent practice
 Frequent, specific feedback (KP)
 Learning: Overcome specificity
 Distributed practice
 Variable practice
 Reduced feedback, focus on KR
Motor Learning in Intervention
 Always!
 Treatment activities should closely match intended movement outcome
 TONS of practice
 Avoid verbose instructions & feedback
 When giving KP, have client attend to perceptual information (biofeedback)
Additional Implications
 When learning strategies are integrated into practice, acquisition will slow
 Outcome assessment must take place outside of practice (therapy) and should incorporate activity and
participation measures
Case studies
Flaccid dysarthria
 49 year old s/p resection of medullary tumor resulting in flaccid dysarthria of CN X, XI, XII and significant
oropharyngeal dysphagia
Predicted impairments?
Assessment strategies?
Functional goals?
Treatment targets?
Intervention plan?
Spastic dysarthria
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 27 year old man s/p viral encephalitis resulting in severe spastic quadriplegia and spastic dysarthria. Speech
limited to undifferentiated vowels. He is married with 3 preschool children and he and his wife own and
manage and flower distribution business
Predicted impairments?
Assessment strategies?
Functional goals?
Treatment targets?
Intervention plan?
Hypokinetic Dysarthria
 Let’s get Mikey!
 40ish male with early onset Parkinsons disease. Symptoms are primarily in limbs but speech deficits are
noticed in “off” cycles of meds. Professional actor by training but now focuses on public speaking events
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Predicted impairments?
Assessment strategies?
Functional goals?
Treatment targets?
Intervention plan?
Ataxic Dysarthria
 49 year old female s/p cerebellar stroke leaving her with severe ataxic dysarthria. She has 3 teenage sons.
Prior to her stroke she was a community leader, serving on the school board, teaching Sunday School, and
directing the local scholarship pageant
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Predicted impairments?
Assessment strategies?
Functional goals?
Treatment targets?
Intervention plan?
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