Establishing Diagnostic
Possibilities
list of diagnostic possibilities can be generated if speech is abnormal. List can grow out of answers to questions:
- Is the problem neurologic?
- If not, is it organic? or psychogenic?
- is it recently acquired or long-standing?
- If neurologic, is it an MSD or some other neurologic communication disorder (e.g. aphasia, akinetic mutism)? If MSD is present, is it dysarthria or apraxia of speech?
- If dysarthria is present, what is its type?
Establishing
a
Diagnosis
possibilities can be ordered from most to least likely.
Then analyzed
Example, if not psychogenic, and dysarthria of undetermined type = existance of organic process and places lesion within motor networks of nervous systemm
if not flaccid dysarthria = lesion is further localized to CNS
–> certain diagnoses can be eliminated or considered unlikely
Purposes of
Motor Speech
Examination
varies; sometimes priority to establish implications of speech diagnosis for localization and neurologic diagnosis; other times formulating treatment reccommendations takes precedence.
Relevant goals to diagnosis:
Description
Establishing Diagnostic Possibilities
Establishing a Diagnosis
Establishign Implications for localization and disease diagnosis
Specifying Severity
Description
Characterizes features of speech & structures and functions that are related to speech.
represents data on which diagnostic & treatment decisions are made
Bases for description come from:
Patient’s history
Description of problem
Oral mech examination
perceptual characteristics of speech
results of standard clinical and instrumental tests.
after description –> SLP decides whether normal or abnormal.
abnormal = interpret meaning
differential diagnosis- process of narrowing diagnostic possibilities and arriving at a specific diagnosis
Differential
Diagnosis
process of narrowing diagnostic possibilities and arriving at a specific diagnosis
Establishing Implications
for
Localization and
Disease Diagnosis
when MSD is identified, address explicitly its implications for localization.
Ex. spastic dysarthria, it is appropriate to state that it is usually associated with bilateral upper motor neuron (UMN) involvement.
if diagnosis already made = appropriate to address compatibility of speech diagnosis with it.
Ex. Parkinsons disease but patient has mixed spastic-ataxic dysarthria = not compatible with PD.
Myasthenia
Gravis
Flaccid Dysarthria that emerges only with speech stress testing and recovers rapidly with rest has very strong association with myasthenia gravis (MG)
Specifying
Severity
Severity of MSD should always be estimated.
Important for 3 reasons:
- can be matched against patient’s complaints
- it influences prognosis and management decision making
- it is part of baseline data against which future changes can be compared.
part of descriptive process
once established, approprite to address implications of findings for prognosis & management.
Guidelines for
Examination
Motor Speech Examination has 3 essential components:
- History
- Identification of Salient Speech Features
- Identification of Confirmatory Signs
Diagnosis made, recommendations formulated & results communicated to patient, referring professionals & others
History
- reveals the time course of complaints
- patient’s observations about disorder
- puts contextual speech on display at a time when anxiety is generally less than formal examination
- when patient may not feel speech is subject of scrutiny
- when physical effort, task comprehension & cooperation are not essential
- 90% of neurologic diagnosis depends on patient’s history
- most clinical neurologic diagnoses are based on speech in its content or manner of expression
- difficult to argue that spoken history provided by patient is less than important to speech evaluation and diagnosis
Salient
Features
- Salient features - those that contribute most directly and influentially to diagnosis
- includes : deviant speech characteristics & their presumed substrates
- 6 features of neuromuscular activity that influence speech production
- Strength
- Speed of movement
- Range of Movement
- Steadiness
- Tone
- Accuracy
Strength
muscles:
- sufficient strength - normal functions
- reserve (excess) strength - permits contraction over time without excessive fatigue; contraction against resistance
Muscle weakness:
- weak muscles cannot contract to desired level
- may fatigue more rapidly
- contraction can be attained but ability to sustain is difficult & decreases quickly
- can affect all 3 major speech valves
- laryngeal
- velopharyngeal
- articulatory
- can be apparent in all components of speech production
- speech breathing
- phonation
- resonance
- articulation
- prosody
- most apparent & dramatic in LMN lesions &t therefore flaccid dysarthrias.
- consequences can be inferred from:
- perceptual & acoustic analyses
- visually at rest
- during speech
- detected during oral mech exam
- measured physiologically
- Abnormalities associated w/ MSDs:
- reduced, usually consistently but sometimes progressively
Speed
- movements during speech are rapid, especially laryngeal, velopharyngeal and articulatory movements that modify expired air to produce multiple phonemes per second for conversational speech
- Excessive speedh is uncommon in MSDs, but can occur with hypokinetic dysarthria.
- excessive speech rate in dysarthria is nearly always associated with decreased range of motion (ROM)
- Slow movements = common in MSDs.
- can be slow to start
- slow in their course
- slow to stop or relax
- single & repetitive movements can be slow
- reduced speech can occur at any of speech valves and during any component of speech production.
- strongly affects prosodic features of speech cause normal prosody is so dependent on quick muscular adjustments that influence rate of syllable production & pitch & loudness variability
- effects of reduced speed most apparent in spastic dysarthria but also present in other dysarthria types
- Abnormalities associated with MSDs
- reduced or variable (increased only in hypokinetic dysarthria)
Phasic speech
movements
- quick, unsustained, & discrete movements needed for conversational speech
- can be produced as single contractions or repetitively
- begins promptly, reaches targets quickly, & relaxes rapidly
- mediated through direct activation UMN pathway input to alpha motor neurons.
Range
- distance traveled by speech structures is precise for single & repetitive movement
- variation in range of repetitive movement is normally present but usually small.
- excessive ROM during voluntary speech is not common in neurologic disease.
- decreased range is common and may occur in context of slow, normal or excessively rapid rate.
- hypokinetic dysarthria is often associated with decreased ROM & sometimes excessively rapid rate.
- other times can be variable & unpredictable.
- abnormal variability in range is common in ataxic & hyperkinetic dysarthrias.
- hypokinetic dysarthria is often associated with decreased ROM & sometimes excessively rapid rate.
- Abnormalities in ROM -
- has major influence on prosodic features of speech = restricted or excessive prosodic variations
- occurs at all of the major speech valves & all components of speech production.
- can be inferred from perceptual and acoustic analyses of speech, speech & nonspeech movements of articulators & measured physiologically.
- Abnormality with MSDs
- reduced or variable (predominantly excessive only in hyperkinetic dysarthrias)
Steadiness
- visible physiologic tremore can occur with extreme fatigue, under emotional stress, or during shivering.
- break downs in neurologic disease categorized by:
- involuntary movements - tremor most common; repetitive, rhythmic oscillations of a body part
- can occur at rest (resting tremor)
- postural tremor - when structure is maintained against gravity
- action tremor - during movement
- terminal tremor - toward end of a movement
- effects most easily seen during vowel production, during speech, oral mech exam
- Dystonias, Dyskinesias, Chorea, Athetosis -
- involuntary movements
- with random, unpredictable, adventitious movements that can vary in speed, duration, and amplitude.
- can be present at rest, during sustained postures or movement
- can affect major speech valves and speech production.
- can affect accuracy & alter prosody & rate.
- primary source of abnormal speech in hyperkinetic dysarthrias.
- involuntary movements - tremor most common; repetitive, rhythmic oscillations of a body part
- hyperkinesias
- Abnormalities associated with MSDs
- unsteady, either rhythmic or arrhythmic
Tone
- in neurologic disease:
- can be excessive or reduced
- fluctuate slowly or rapidly in regular or unpredicatble ways
- can occur at any speech valves and level of speech production
- Abnormal tone = associated with
- flaccid dysarthrias –> consistently reduced
- spastic or hypokinetic dysarthrias –> when consistently increased
- hyperkinetic dysarthrias –> variable.
- Abnormalities associated with MSDs -
- increased, decreased or variable
Accuracy
- the outcome of well-timed & coordinated activities of all teh other neuromuscular features
- if strength, speed, rangle, steadiness, and tone have been properly regulated, speech movements should be accurate.
- innacurracies + normal neuromuscular performance = linguistic plan or ideational content is defective –> source of problem is outside motor system
- force + excessive ROM = structures may overshoot targets
- force + ROM decreased = target undershooting
- Timing is poor - directions & smoothness of movements would be faulty & rhythm of repetitive movements maintained poorly
- inaccuracies can occur in any of speech valves & any level of speech production
- perceived most easiy in articulation & prosody
- can occur in all dysarthrias:
- inadequate timing/coordination = usually ataxic dysarthria or AOS
- random or unpredictable involuntary variations in movement = hyperkinetic dysarthria
