Speech Disorders Unit 3

Motor Speech Disorder Definition

A disorder of speech resulting from neurological impairment affecting the motor programming or neuromuscular execution of speech

Motor Speech Disorders Types/Impairments

Includes dysarthria and apraxia of speech

Other oral movements may be impaired, including chewing and smiling

May co-occur with language impairments

Speech disorder resulting from weakness, paralysis, or incoordination of the muscles of the speech mechanism

Dysarthria Definition

Speech disorder which results from an impairment in (sensori)motor programming for volitional speech

• No problems with the muscles themselves, just the programming

Apraxia Definition

Motor Speech Disorders Causes

Acquired: stroke, TBI, degenerative diseases

Developmental: cerebral palsy, developmental disabilities

Upper and Lower Motor Neurons

Upper: motor areas of cerebral cortex & some subcortical structures

• Initiate voluntary movement

Lower: connect brain & spinal cord to muscle fibers

• “Final common pathway”: nerve impulses = contraction of muscle fibers

Types of Dysarthria

Flaccid

Spastic

Ataxic

Hypokinetic

Hyperkinetic

Mixed (1/3 of patients)

Lesion Site: Lower Motor Neuron

Primary Defect: Weakness

Flaccid Dysarthria

Lesion Site: Upper Motor Neuron

Primary Defect: Spasticity

Spastic Dysarthria

Lesion Site: Cerebellum

Primary Defect: Incoordination

Ataxic Dysarthria

Lesion Site: Basal Ganglia Circuit

Primary Defect: Rigidity, Reduced ROM

Hypokinetic Dysarthria

Lesion Site: Basal Ganglia Circuit

Primary Defect: Involuntary Movement

Hyperkinetic Dysarthria

Lesion Site: More than one of above

Primary Defect: Multiple

Mixed Dysarthria

Flaccid Dysarthria Causes

Uni/bilateral LMN stroke (brainstem stroke)

Myasthenia gravis

Muscular dystrophy

Flaccid Dysarthria Signs

Muscle weakness

Reduction of muscle reflexes

Loss of muscle tone

Atrophy of muscles

Fasciculations

Damage to nerves VI and VII

Clear speech with very little facial movement

Moebius Syndrome

Problem at neuromuscular junction: fluctuating muscle weakness and fatigue

ACh is attacked by antibodies so muscle can’t contract

Speech Sample: Slurred/imprecise speech, resonance problems, difficultly chewing & swallowing

Myasthenia Gravis

Muscular Dystrophy

Genetic

Degenerative & progressive

Diffuse, chronic effects

• Main symptom is muscle weakness

Over 30 types but 9 major forms

• Duchenne

• Becker

• Myotonic

Spastic Dysarthria Signs

Spastic paralysis (stiff, contracted muscles)

Hyperactive and pathological muscle reflexes

Strained/harsh voice, slow & labored speech

Ataxic Dysarthria Causes

Cerebellar lesions

Coordinates and sequences speech movements

Integrates sensory feedback into revised production

Ataxic Dysarthria Signs

Inaccurate/irregular movements

Impaired prosody

Can sound “drunk”

Hypokinetic Dysarthria Cause

Basal ganglia damage

• Reduces movement or leads to failure to inhibit involuntary movement

Depletion/insufficiency of dopamine = reduced movement

Prototypical example: Parkinson’s disease

Hypokinetic Dysarthria Signs

Most evident in voice, articulation, and prosody

Reduced loudness

Short rushes of speech

Reduced respiratory movement

Medical Management

Levadopa (L-DOPA): precursor to dopamine, can cross blood-brain barrier whereas DA cannot

Given with another drug to prevent the peripheral synthesis of dopamine from L-DOPA

Side Effects of L-DOPA

Akinesia/dyskinesia

Rigidity/stiffness

“On-Off Response”: Phases of immobility and incapacity associated with depression alternating with jubilant “thaws”

Extreme emotional state (anxiety, hypersexuality), confusion, hallucinations

Hyperkinetic Dysarthria

Basal Ganglia Damage

Huntington’s Disease

Types of Involuntary Movements

• Tardive Dyskinesia

Tardive Dyskinesia

Repetitive, involuntary, jerky, purposeless movements

Often a side effect of medication

Mixed Dysarthria

Amyotrophic Lateral Sclerosis (ALS): mixed flaccid/spastic

Cerebral Palsy: several types

CP Overview

Non-progressive (symptoms may change with age)

Muscles are weak, stiff, and/or uncoordinated

Most common childhood movement disability in US

1/3 of people DO NOT have cognitive impairment

Initial Signs of CP

Maintenance of primitive reflexes

• Asymmetric tonic neck reflex

• Positive supporting reaction: leg muscles contract in a straight standing position when balls of feet make contact with solid surface

• Moro reflex: reaction to loss of support/feel of falling

• Sucking, rooting, and biting reflexes

Delayed developmental milestones

Classifications of CP

Spastic

Dyskinetic (athetoid)

Ataxtic (dystonic)

Mixed

Mild Case

Acquired Apraxia of Speech

Result of brain injury

Impaired motor planning/programming

Difficulties only with voluntary movement for speech. Non-speech tasks remain unaffected

Prosody and articulation are disrupted

Articulation in Apraxia Patients

Slow/effortful

Initiation difficulty

Inconsistent errors (close to target)

Errors increase with complexity

Movement in Apraxia Patients

Groping Articulators

Silent Posturing

Prosody in Apraxia Patients

Due to compensation

Impaired stress, slow/effortful rate, prolonged phonemes, odd pauses

Apraxia of Speech: Fluency

Restarts and repeated attempts at producing a word or sound, and syllable repetitions

Articulatory groping, sometimes with facial grimacing

Initiation of utterances especially problematic

Not the same as stuttering!

Concomitant Apraxia

Oral apraxia

Limb apraxia

Oral Apaxia

Problems with voluntary oral nonspeech movements

e.g., blowing a kiss, smiling, etc.

Movements are okay when they are reflexive

Limb Apraxia

Problems with voluntary arm movements

Evaluation Components

History

Oral Motor Examination

Perceptual Assessment

Intelligibility Assessment

Acoustic & Physiological Measures

Dysdiadochokinesis

Measure how quickly and accurately a person can produce alternating and sequential articulatory movements

AMR: alternating motion rate

• Say “pa-pa-pa-pa…” as fast as you can

SMR: sequential motion rate

• Say “pa-ta-ka-pa-ta-ka…” as fast as you can

Speech Intelligibility Measure

Measure in connected speech, not single words most of the time

Two primary approaches to measuring intelligibility

• Word-identification approaches

• Scaled ratings

Differential Dx: Dysarthria, Spastic

Strained-strangled phonation, hypernasality, imprecise consonants, impaired stress

Differential Dx: Dysarthria

Flaccid

Breathy, imprecise consonants, hypernasal

Differential Dx: Dysarthria

Hypokinetic

Decreased loudness, poor vocal quality, imprecise consonants

Differential Dx: Dysarthria

Hyperkinetic

Involuntary movements, variable rate, strained phonation, hypernasality, imprecise consonants

Differential Dx: Dysarthria

Ataxia

Irregular articulatory breakdowns, impaired prosody

Differential Dx: Apraxia of Speech

Phonetic Complexity

Test along a hierarchy of phonetic complexity

• rain → train → strain

• come → compute → computer → computation → computational

Differential Dx: Apraxia of Speech

Cueing for Response

Test along a hierarchy of cues (no feedback → visual → tactile)

Test along a hierarchy of timing between cue and response (simultaneous → immediate → with delay)

Differential Dx: Apraxia of Speech

Length of utterance

Test along a hierarchy of lengths

• I → I eat → I eat lunch and so on

Differential Dx: Apraxia of Speech

Linguistic complexity

Test along a hierarchy of linguistic load

• Repetition → Conversation → Picture Description → Narrative

Management Approaches for Dysarthria

1. Medical Management

   1. Surgical management

   2. Pharmacologic management

   3. Prosthetic management

2. Behavioral Management (speech therapy)

Surgical Management

Deep Brain Stimulation

Thyroplasty

Pharyngeal Flap Surgery

Pharmacologic Management

Usually directed at relieving symptoms of the larger disease/disorder

Improvement in general function may not be accompanied by commensurate change in speech function

Know the drug the client is taking and for what

Begin other therapy when the effects are stable

Prosthetic Management

Includes the use of any device to improve function

• Palatal lift prosthesis, amplification system, AAC, pacing board, DAF, biofeedback devices

• ACC can be used to replace or supplement existing speech

• Consider surgery, prosthetics before behavioral therapy if possible

Behavioral Management

1. Improve impaired system(s)

2. Teach compensatory strategies

Therapy can be: speaker-oriented or communication-oriented

Establish alternative form of communication if needed in early stages

Begin with a feature which can be modified readily and with minimal instruction

Speaker-Oriented Therapy

Focus on changing the speaker behavior (improve function or compensations)

Communication-Oriented Therapy

Focus on changing the behavior of listeners or the environment

Progressive neurodegenerative disorder that affects nerve cells in the brain and spinal cord, leading to loss of muscle control

Muscle weakness, twitching, cramping, difficulty speaking, swallowing, and breathing, paralysis and significant respiratory issues

ALS/Lou Gehrig’s Disease

Neurodegenerative disorder caused by the loss of dopamine-producing neurons in the substantia nigra

Resting tremors, muscle rigidify and stiffness, bradykinesia, postural instability, cognitive decline in later stages

Parkinson’s Disease

Genetic disorder leading to the progressive breakdown of neurons, especially in the basal ganglia

Involuntary jerking, or writhing movements (chorea), cognitive decline, psychiatric symptoms, loss of motor control

Huntington’s Disease

Deep Brain Stimulation

Surgically implanting electrodes into specific brain regions to deliver controlled electrical impulses to help regulate abnormal neural activity

Dysarthria or Apraxia of Speech

• Motor speech execution disorder

Dysarthria

Dysarthria or Apraxia of Speech

• Motor speech programming disorder

AOS

Dysarthria or Apraxia of Speech

• Muscles have reduced range, strength

Dysarthria

Dysarthria or Apraxia of Speech

• Consistent errors

Dysarthria

Dysarthria or Apraxia of Speech

• No island of clear speech

Dysarthria

Dysarthria or Apraxia of Speech

• Consonants imprecise

Dysarthria

Dysarthria or Apraxia of Speech

• No weakness or paralysis

AOS

Dysarthria or Apraxia of Speech

• Inconsistent errors

AOS

Dysarthria or Apraxia of Speech

• Island of clear speech

AOS

Dysarthria or Apraxia of Speech

• Errors increase with complexity

AOS

Trigeminal Nerve (V)

Jaw Movements

Facial Nerve (VII)

Facial and lip movement

Vagus Nerve (X)

Larynx, pharynx, velopharynx

Controls phonation, resonance, and swallowing

Hypoglossal Nerve (XII)

Tongue movement

Prenatal Causes of CP

Genetics, agenesis, viruses, anoxia

Perinatal Causes of CP

Anoxia due to cord compression, blockage of the airways, aspiration pneumonia, hypoxia due to use of narcotics during birth

Postnatal Causes of CP

Brain injury, high fevers, meningitis encephalitis