Ataxic Dysarthria

Question 1

Definitions of Ataxic Dysarthria

Answer 1

Motor speech disorder often due to damage to cerebellum or its neural pathways

Question 2

Speech errors in Ataxic Dysarthria

Answer 2

Results in speech errors that are primarily articulatory and prosodic, giving speech unsteady, slurred quality

Question 3

Neurologic Basis of Ataxic Dysarthria

Answer 3

Caused by damage to cerebellum or neural pathways that connect cerebellum to other parts of central nervous system

Question 4

Cerebellum

Answer 4

Primary function: coordinate timing and force of muscular contractions. Processes sensory information from all over body and integrates information into execution of movement

Question 5

“Ataxia”

Answer 5

Widespread incoordination; Greek word for “lack of order”

Question 6

Neural Pathways to and from the Cerebellum

Answer 6

Cerebellum
Attached to brainstem
Communicates with rest of CNS through three bundles of neural tracts called cerebellar peduncles

Question 7

Inferior peduncle allows cerebellum to

Answer 7

Receive sensory information from entire body about position of body parts
Recognize what body is doing during movement and whether motor impulse to muscles is accomplishing intended result
Monitor timing and force of movements while performed

Question 8

Middle peduncle allows cerebellum to

Answer 8

Receive preliminary information from cortex regarding planned movements
Coordinate planned movements by integrating sensory information from body with individual’s experience of what appropriate movement should be, smoothing and refining according to current conditions

Question 9

Superior peduncle allows cerebellum to

Answer 9

Have main output to rest of CNS

Send its processed motor impulses to motor areas of cortex, completing corticocerebellar control circuit

Question 10

Cerebellar control circuits

Answer 10

neurons that course through three cerebellar pathways

Not called upper motor neurons because do not synapse with lower motor neurons

Question 11

Two ways cerebellum influences speech movements

Answer 11

1. Through corticocerebellar control circuit

Planned motor impulses of planned speech act sent from cortex to cerebellum
Cerebellum coordinates and refines preliminary movements
Coordinated motor impulses then sent to thalamus for more refinement before sent to motor cortex and then to muscles

2. Through its connections to extrapyramidal system

Makes rapid adjustments in timing and force of movements to compensate for unexpected changes in circumstances of movement

Question 12

Causes of Ataxic Dysarthria

Answer 12

Damage to cerebellum or its control circuits causing difficulties coordinating voluntary movements

Cerebellar ataxia: movement deficits of timing, force, range, and direction

Vermis: midpoint of cerebellum between cerebellar hemispheres upon which speech coordination is highly dependent

Question 13

Degenerative Diseases

Autosomal dominant cerebellar dysfunction of late onset

Answer 13

Hereditary disease usually beginning in middle age

Question 14

Degenerative Diseases

Idiopathic sporadic late-onset cerebellar ataxia

Answer 14

Similar to autosomal dominant cerebellar dysfunction, but does not include as many neurologic symptoms

Question 15

Degenerative Diseases

Friedreich’s ataxia

Answer 15

Progressive hereditary disease affecting spinal cord as well as cerebellum

Question 16

Degenerative Diseases

Olivopontocerebellar degeneration

Answer 16

Progressive cerebellar disorder that runs in families

Question 17

Stroke

Answer 17

Cerebellum has rich arterial blood supply
Arteries serving cerebellum:
Superior cerebellar, anterior inferior cerebellar artery

Ataxic dysarthria can result in:
Blockage to arteries serving cerebellum, ruptured aneurysms, arteriovenous malformations

Cerebellar signs: limb ataxia, problems with balance, visual deficits, ataxic dysarthria

Question 18

Toxic conditions

Answer 18

Most treatable with ataxic dysarthria resolving as toxic levels decrease
Lead and mercury poisoning
Long- and short-term alcohol consumption
Exposure to chemicals such as acrylamide and cyanide
Toxic levels that may not be irreversible
Phenytoin (Dilantin): antiseizure drug

Question 19

Metabolic conditions

Answer 19

Vitamin E or B12 deficiency
Severe cases of hypothyroidism
Hereditary disorders such as Wilson’s disease

Question 20

Traumatic Head Injury

Answer 20

Trauma to cerebellum tends to be diffuse, as with most head injuries
Cerebellar peduncles especially vulnerable to twisting and rotational forces because cerebellum essentially an appendage attached to brainstem

Question 21

Tumors

Answer 21

Extent of ataxic dysarthria depends on location and size of tumor

Tumor can affect cerebellar function by:
Growing in cerebellar tissue, perhaps directly destroying and compressing cerebellum

Growing near cerebellum, thereby compressing cerebellar tissue

Interfering with functions of cerebellar control circuits

Question 22

Metastatic tumors

Answer 22

Among most common

Formed when primary tumor sheds cancerous cells that seed a secondary (metastatic) tumor

Question 23

Low-grade actrocytoms

Answer 23

Slow-growing type of tumor appearing frequently in cerebellum, especially in children

Question 24

Hemangioblastomas

Answer 24

Benign tumors of proliferated blood vessels found occasionally in cerebellum

Question 25

Not common causes

Answer 25

Viral infections invading cerebellum

Infections such as trichinosis, typhus, and syphilis

Bacterial abscess near cerebellum that compresses surrounding brain tissue

Question 26

Speech Characteristics of Ataxic Dysarthria

Answer 26

Movements appear poorly coordinated
Problems controlling timing/force for speech
Slurred, monotonous articulation
Primarily disorder of articulation and prosody

Scanning speech:
Term to describe ataxic dysarthria, describing slow, deliberate production of syllables, with each syllable in word receiving equal stress

Question 27

Articulation

Answer 27

Articulation deficits significant problem

Imprecise consonant production is the most prevalent speech error

Distorted vowels

Imperfect articulation gives ataxic dysarthria slurred quality

Caused by cerebellar damage disrupting timing, force, range, and direction of movements

Irregular articulatory breakdowns: Imprecise consonant and vowel productions vary from utterance to utterance

Decomposition of movement: manifestations of cerebellar dysfunction, where instead of smooth coordinated movements, they are distinct and jerky

Question 28

Prosody

Answer 28

Equal and excess stress is a distinguishing characteristic of ataxic dysarthria

Prolonged phonemes and prolonged intervals between phonemes

Slow movement on both single and repetitive motion tasks; hypotonia

Monopitch and monoloudness

Caused by hypotonia of speech muscles

Question 29

Phonation

Answer 29

Few phonatory deficits noted in ataxic dysarthria

Harsh vocal quality

Caused by decreased muscle tone in laryngeal and respiratory structures, preventing full contraction of these muscle groups

Voice tremor

Question 30

Resonance

Answer 30

Hypernasality
Seldom serious problem in ataxic dysarthria

Hyponasality
Intermittent
Caused by timing errors between muscles of velum and other muscles of articulation

Question 31

Respiration

Answer 31

Uncoordinated movements in respiratory muscles, contributing to speech deficits

Paradoxical movements: movements that occur when muscles work against each other rather than in coordination

Paradoxical movements of intercostal muscles and diaphragm

Leads patient to speak on residual air, which can lead to increased rate of speech, decreased loudness, and harsh vocal quality

Question 32

Key Evaluation Tasks for Ataxic Dysarthria

Answer 32

Speech alternate motor tasks

• Slower than normal, difficulty maintaining steady rhythm with repetition
• Severe cases: speed up abruptly then unexpectedly slow down

Reading, conversational speech, and repeating sentences containing numerous multisyllabic words

Question 33

Treatment of Ataxic Dysarthria

Answer 33

Damage affects speed, force, and timing of movements of articulators, resulting in uncoordinated movement

Most evident speech errors related to articulation and prosody

Question 34

Respiration Treatment

Answer 34

Do not need to address strengthening respiration

Concentrate on controlling airflow more accurately during speech, as uncoordinated movements of respiratory muscles cause speech on residual air, affecting prosody and phonation

Tasks to help improve breath control during speech

• Slow and controlled exhalation
• Speak immediately on exhalation
• Stop phonation early
• Optimal breath group: teaching how may syllables or words can be said clearly on one full inhalation

Question 35

Prosody Treatment

Answer 35

Prosodic problems involve:
Rate, stress, and intonation

By slowing rate, can improve intelligibility
By incorporating more typical stress and intonation into utterances, speech may exhibit more natural quality

Rate control
Slow, irregular rate characteristic of ataxic dysarthria, but may attempt to speak too rapid for speech capabilities
Articulators are not given enough time to reach target positions
Listener not given enough time to assimilate spoken message

Question 36

Articulation Treatment

Answer 36

May improve with slowed rate
Need to concentrate directly on improving production of phonemes

Articulation tasks

• Intelligibility drills
• Phonetic placement
• Exaggerating consonants (overarticulation)
• Minimal contrast drills

Question 37

Speech characteristics include

Answer 37

Imprecise consonant production and irregular articulatory breakdowns

Question 38

Ataxic dysarthria caused by

Answer 38

any process resulting in damage to cerebellum or cerebellar control circuits

Question 39

Common causes include

Answer 39

degenerative diseases and stroke

Question 40

Most significantly affected speech characteristics

Answer 40

Articulation and prosody

Question 41

Treatment concentrates on:

Answer 41

• Controlling respiration for speech
• Increasing articulatory accuracy
• Developing optimal rate and intonation in -Connected speech