CH1-Define,Understand,Categorize MSDs

Question 1

Name the motor speech planning processes

Answer 1

1. Cognitive-linguistic processes
2. Motor speech planning, programming, and control
3. Neuromuscular execution

Question 2

Cognitive-linguistic processes

Answer 2

Organization of communicative intent (verbal intent to express thoughts, feelings, and emotions) into a code that abides by the rules of language.

Question 3

Motor speech planning, programming, and control

Answer 3

• intended verbal message must be organized for neuromuscular execution.
• includes:
  
  • selection
  • sequencing
  • regulation
    
    • of sensorimotor “programs” that activate speech muscles at appropriate times, durations, and intensities.

Question 4

Neuromuscular execution

Answer 4

• The neural and neuromuscular transmission and subsequent muscle contractions and movements of speech structures
  
  • CNS and PNS activity must combine to executes speech motor programs
  • innervates breathing, phonatory, resonatory, and articulatory muscles in manner that generates an acoustic signal that reflects the goals of the programs.

Question 5

Motor Speech Disorders

Answer 5

• speech disorders resulting from neurologic impairments affecting the planning, programming, control or execution of speech.
• includes :
  
  • Dysarthrias
  • Apraxia of Speech

Question 6

Dysarthria definition

Answer 6

• group of neurologic speech disorders that reflect abnormalities in :
  
  • strength
  • speed
  • range
  • steadiness
  • tone
  • accuracy
    
    • of movements needed for the breathing, phonatory, resonatory, articulatory, or prosodic aspects of speech production.
• includes :
  
  • weakness
  • spasticity,
  • incoordination,
  • involuntary movements,
  • excessive or variable muscle tone.

Question 7

Describe Dysarthria

Answer 7

1. neurologic in origin
2. disorder of movement
3. categorized into different types
   
   1. each type is characterized by distinguishable perceptual characteristics and underlying neuropathophysiologic factors
   2. ability to categorize has implications for localization of causal disorder

Question 8

Apraxia of Speech Definition

Answer 8

• neurologic speech disorder
• reflects impaired capacity to plan or program sensorimotor commands necessary for directing movements
• results in phonetically and prosodically disordered speech.
• can occur in absence of physiologic disturbance in any component of language.

Question 9

Speech disturbances distinguishable from MSDs

Answer 9

• Other neurologic speech disturbances
  
  • e.g. neurogenic stuttering, palilalia, echolalia, foreign accent syndrome, aprosodia associated with r. hemisphere dysfunction, some forms of mutism
• Cognitive, Linguistic, and Cognitive-Linguistic disturbances
  
  • changes in verbal expression from language and other cognitive deficits (e.g. aphasia, akinetic mutism, other cognitive disturbances that inhibit speech)
  • sometimes difficult to distinguis from MSDs due to co-occurance –> complicates examination & diagnosis.
• Sensory Deficits
  
  • effects of deafness on speech development in childhood, and degradation of speech in adult acquired deafness
  • Hearing loss effects on speech production are distinguishable from MSDs.
  • Tactile, kinesthetic, proprioceptive sensation disturbances implicated in certain MSDs.
• Nonneurologic Disturbances
  
  • Musculoskeletal Defects (e.g. laryngectomy, cleft lip & palate, fractures, abnormal variants of cavity size & shape.
  • Nonneurologic and nonpsychogenic voice disorders (e.g. dysphonias associated with head/neck neoplasms, vocal abuse, hormonal disturbances)
• Functional (psychogenic) & related nonorganic speech disorders
  
  • changes from abnormal psychological states (e.g. schizophrenia, depression, conversion disorder, subconcious learning or maladaptive compensation) can be in people who are otherwise psychologically healthy.
  • can be difficult to distinguish from organic, structural neurologic disease; can accompany organic neurologic abnormalities.
• Normal variations in Speech Production
  
  • Age-related changes in speech - normal aging causes changes in pitch, voice quality, stability, loudness, breathing, rate, fluency, prosody and fine motor control; can be similar to those associated with dysarthria
  • Gender- differences in men/women can influence detection of abnormalities
  • Variations in style - variations of personality, emotional state, and speaking role must be considered for differential diagnosis and treatment decision making.

Question 10

2 Categories of Methods for

Studying Motor Speech Disorders

Answer 10

1. Perceptual Methods - relies primarily on auditory perceptual attributes of speech
   
   • *Gold Standard - for clinical differential diagnosis, judgements of severity, management decisions, and assessment of meaningful temporal change.
2. Instrumental Methods - 3 categories - acoustic, physiologic, and visual imaging
   
   • not widely used; may be due to lack of widely accepted standards and normative data, limited experience
   • contributes to description and understanding of MSDs & need for systematic research.

Question 11

Perceptual Methods for studying MSDs

Answer 11

• Gold Standard
• relies on auditory perceptual attributes of speech
• subject to unreliability among clinicians, difficult to quantify, cannot directly test hypotheses about pathophysiology underlying perceived speech abnormalities
• Evaluations of speech disorder always begins with perceptual judgement –> unlikely to be replated by other methods.
• Darley, Aronson, and Brown (DAB) pioneered modern use of auditory-perceptual assessment to characterize the dysarthrias and id clusters of salient perceptual characteristics associated with lesions in different portions of CNS and PNS.
  
  • referred to DAB approach or Mayo approach

Question 12

Instrumental Methods of studying MSDs

Answer 12

1. Acoustic - visually display and numerically quantify frequency, intensity, and temporal components of speech signal.
2. Physiologic- moves “upstream” towards sources of activity that generate & control speech to establish relationship between pathophysiology and acoustic perceptual attributes of MSDs.
3. Visual Imaging - instruments used for visually imaging parts of upper aerodigestive tract during speech; videodflouroscopy, nasoendoscopy, laryngoscopy, and videostroboscopy

Question 13

Acoustic Methods for studying MSDs

Answer 13

• can visually display and numerically quantify frequency, intensity and temporal components of speech signal.
• tightly linked to auditory-perceptual judgements of speech because use same data (the speech signal)
• Auditory speech signal important part of speech motor control –> strong justifications for use of acoustic methods in children and adults
• Quantitatively confirms/supports perceptual judgements of :
  
  • speech rate (slow)
  • voice characteristics (breathy, contains tremore or interrruptions)
  • pitch and loudness variability
  • resonance (hypernasal
  • articulation (imprecise
  • speech diadochokinetic rates (irregular)
• Instruments are affordable, accessible and efficient.
  
  • Rhythm metrics, envelope modulation spectra
  • can distinguish apraxia from normal speech and aphasia
• can provide quantifiable data for baseline, stability, improvement or deterioration over time & visual feedback for therapy.

Question 14

Physiologic Methods for studying MSDs

Answer 14

• examines sources of activity that generate and control speech.
  
  • provides different explanation for disordered speech.
• Focuses on one or more of the following:
  
  • Muscle contractions that generate movement
  • movements of speech structures and airflow
  • relationships among movements at different levels of the musculoskeletal speech system
  • temporal parameters and relationships among central and peripheral neural and biomechanical activity
  • temporal relationships withing and among CNS structures and networds during the planning, programming, and control of speech.
• Crucial in establishing relationship between pathophysiology (e.g. weakness, spasticity, incoordination) and acoustic & perceptual attributes of MSDs.
• Most common methods used - study movemnt of air and peripheral structures
  
  • electromyography, kinematic measures (electroglottography, magnetometry) and aerodynamic measures (spirometry, nasal accelerometry).
  • methods for imaging physiologic activity in CNS
    
    • fMRI - functional magnetic resonance imaging
    • PET - positron emission tomography
    • SPECT- single-photon emission computed tomography
    • EEG - multichannel electroencephalography
    • TMS - transcranial magnetic stimulation
    • MEG - magnetoencephalography
• has challenged perceptually based explanations for pathophys. of certain MSDs by clarifying whether disorders reflect weakness, spasticity, incoordination, reduced range of movement, etc.

Question 15

Visual Imaging Methods for studying MSDs

Answer 15

• Instruments used to visually image parts of upper aerodigestive tract during speech
• straddles boundary between perceptual and physiologic measures
• widely used for clinical purposes
• common methods: (all can be recorded, saved & analyzed)
  
  • videofluoroscopy
  • naseoendoscopy
  • laryngoscopy
  • videostroboscopy
• used to evaluate swallowing and velopharyngeal and laryngeal functions for speech.
• can strongly influence diagnosis and management recommendations when used in combination with auditory perceptual analysis.
• can be subject to challenges of reliability

Question 16

Clinical Salience of Perceptual Analysis

of Motor Speech Disorders

Answer 16

1. Evaluation of suspected MSD begins with perceptually based speech assessment.
   
   • instrumental assessments that follow is directed and motivated by results of perceptual assessment.
   • if descriptive/diagnostic errors are made at perceptual entry point, what follows can be misguided or misleading to diagnosis and management.
2. Perceptually based methods should be the foundation of clinical practice.
   
   • usefulness of perceptually based differential diagnosis is relative to contribution to localization and diagnosis of neurologic disease & has been established
     
     • other methods contributions to or modify usefulness is not yet clear.
     • need to include adequate description of salient perceptual speech characteristics in any research that examines the acoustic or physiologic attributes of MSDs.
3. standard for judging functional outcomes of management of MSDs is most often based on auditory perceptual judgements of speech & its intelligibility, comprehensibility, and efficiency.

Question 17

Categorizing MSDs

Answer 17

Variables relevant to neurologic and etiologic perspectives include:

1. Age at onset - congenital (developmental) or acquired
2. Course -
   
   • congenital ( cerebral palsy)
   • chronic or stationary ( cp in adults; plateau after stroke)
   • improving (during spontaneous recovery from a stroke or closed head injury)
   • progressive or degenerative (amyotrophic lateral sclerosis or PD)
   • exacerbating - remitting ( multiple sclerosis)
3. Site of Lesion - lesions associated with MSDs can include :
   
   • neuromuscular junction
   • peripheral and cranial nerves
   • brainstem
   • cerebellum
   • basal ganglia
   • pyramidal or extrapyramidal pathways
   • cerebral cortex

• establishing lesion site is primary goal of neuro evaluations
• knowledge of lesion site can predict certain speech deficits, raise doubts with incompatibility of findings and lesion sites, or suggest presence of additional lesions or different diseases.

4. Neurologic diagnosis - broad categories include:

• degenerative
• inflammatory
• toxic-metabolic
• neoplastic
• traumatic
• vascular
  
  • more specific diagnoses are applied within categories
  • Types of MSDs are found commonly in some neurologic diseases and rarely in others. (PD = hypokinetic dysarthria)

5. Pathophysiology - presence of certain speech abnormalities or combinations of them suggest one or more pathophysiologic disturbances and vice versa.
   * underlying pathophysiology (weakness, spasticity) determines distinctive pattern of speech deficits associated with each MSD.

Question 18

Major types of motor speech disorders

and their

localization and neuromotor bases

Answer 18

Question 19

Flaccid Dysarthria

localization & neuromotor bases

Answer 19

• Type - Flaccid
• Localization - lower motor neuron (final common pathway, motor unit)
• Neuromotor Bases (general) - Execution
• Neurologic (specific) - Weakness

Question 20

Spastic Dysarthria

localization & neuromotor bases

Answer 20

Type - Spastic

Localization - bilateral upper motor neuron (direct and indirect activation pathways)

Neuromotor Bases (general) - Execution

Neurologic (specific) - Spasticity

Question 21

Ataxic Dysarthria

localization and neuromotor bases

Answer 21

Type - Ataxic

Localization - Cerebellum (cerebellar control circuit)

Neuromotor Bases (general) - Control

Neurologic (specific) - Incoordination

Question 22

HypokineticDysarthria

localization and neuromotor bases

Answer 22

Type - Hypokinetic

Localization - Basal ganglia control circuit (extrapyramidal)

Neuromotor Bases (general) - Control

Neurologic (specific) - Rigidity; reduced range of movement; scaling problems

Question 23

Hyperkinetic Dysarthria

localization and neuromotor bases

Answer 23

Type - Hyperkinetic

Localization - Basal ganglia control circuit (extrapyramidal)

Neuromotor Bases (general) - Control

Neurologic (specific) - Involuntary movements

Question 24

Unilateral Upper Motor Neuron Dysarthria

localization and neuromotor bases

Answer 24

Type - Unilateral Upper Motor Neuron

Localization - Unilateral Upper Motor Neuron

Neuromotor Bases (general) - Execution/control

Neurologic (specific) - Upper motor neuron weakness, incoordination, or spasticity

• occurs commonly in patients with unilateral cerebral lesions
• often occurs with aphasia and apraxia of speech
• considered a sign (sometimes only sign) of unilateral stroke by neurologists

Question 25

Mixed Dysarthria

localization and neuromotor bases

Answer 25

Type - Mixed

Localization - More than one

Neuromotor Bases (general) - Execution and/or control

Neurologic (specific) - More than one

• includes all possible combinations of single types, each mix having various predictable/unpredicatble relationships with neurologic diseases.

Question 26

Undetermined Dysarthria

localization and neuromotor bases

Answer 26

Type - Undetermined

Localization - ?

Neuromotor Bases (general) - ?

Neurologic (specific) - ?

• included to recognize explicitly that perhaps not all perceptually distinct dysarthria types have been formally recognized & subcategorization of already recognized dysarthrias may someday be justified.
• recognizes a speech disorder may be recognized as dysarthria, its manifestations may be subtle, complicated, or unusual to lead to a clinical diagnosis of undetermined.

Question 27

Apraxia of Speech

localization & neuromotor bases

Answer 27

Type - Apraxia of Speech

Localization - Left (dominant) hemisphere

Neuromotor Bases (general) - Motor planning/programming

Neurologic (specific) - planning/programming errors