AOS defined
- motor speech disorder “resulting from impairment, as a result of brain damage, of the capacity to program the positioning of speech musculature and the sequencing of muscle movements for the volitional production of phonemes
- no significant weakness, slowness, or incoordination in reflex or automatic acts
- prosodic alterations may be associated with the articulatory problem, perhaps in attempts to compensate
Overview of AOS
- neurological deficit in the production of speech sounds
- occurs in the absence of muscle weakness, abnormal muscle tone, reduced ROM, or decreased muscle steadiness
- a deficiency in the ability to accurately sequence the movements needed to produce speech sounds
- probably should be referenced as dyspraxia as there is “disordered action” not a lack of movement
- HALLMARK- inconsistency
- No tone issues if there is it could be spasticity, flaccidity, or mixed
- No weakness, nothing wrong with the muscle, no incoordination (incoordination makes us think of ataxia (cerebellar)
Two forms of AOS
[1] ideational apraxia
[2] ideomotor apraxia
Ideational Apraxia
- inability to make use of an object or gesture because the individual has lost the knowledge (or idea) of the object’s or gesture’s function
- disturbance in the conception of an object/gesture
- uncommon disorder that typically results from damage to the left parietal lobe
- often goes undetected masked by other disorders (i.e., aphasia)
- difficult to detect as it resolves quickly when caused by a stroke
- ideational (disconnect with idea) they don’t know how to use the object (motor plan it)
- Roof of lichtim’s diagram- thoughts and concepts, disturbance in the conception of an object or gesture
Ideomotor apraxia
- disturbance in the performance of the movements needed to use an object, make a gesture, or complete a sequence of individual movements
- AOS is one of the ideomotor apraxias
- typically affects the voluntary movements more so than the automatic movements
- there are at least three (3) subcategories of ideomotor apraxia
[1] limb apraxia- bilateral or unilateral
[2] nonverbal oral apraxia
[3] AOS
- When you think of apraxia think of inconsistency, groping, prosody issues
Limb Apraxia
- inability to sequence the movements of the arms, legs, hands, or feet during a volitional action
- often results from left hemisphere damage
- affects both the right/left limbs, although hemiplegia may hide its effects on one side of the body
Nonverbal Oral Apraxia
- aka: oral apraxia, buccofacial apraxia, facial apraxia or lingual apraxia
- deficit in the ability to sequence nonverbal voluntary movements of the tongue, lips, jaw, and other associated oral structures
- individuals will grope for the correct position, delay performing the action, add extra unnecessary movements
- commonly seen in those suffering left hemisphere damage; can co-occur with aphasia
- can co-occur with AOS or verbal apraxia of speech
- Difference between nonverbal oral apraxia- can’t do oral motor tasks (you will see groping, and inconsistencies- you ask them to protrude their tongue and they pop their lips- can’t motor plan)
AOS
- deficit in the ability to sequence the motor commands needed to correctly position the articulators during voluntary production of phonemes
- usually caused by damage to the left frontal lobe, especially when damage occurs near Broca’s area
- Duffy suggests it can co-occur with UUMN dysarthria
AOS etiologies
- AOS is typically the result of injury to the perisylvian area of the left hemisphere of the brain
- injuries to the insula and the basal ganglia have also been know to cause AOS
- specific etiologies: CVA, degenerative disease, trauma, tumor
— most common is CVA (58%)
— degenerative disease: Alzheimer’s, PPA, Creutzfeldt-Jakob disease (16%)
— trauma (15%); typically surgical trauma
(11%) were tumor related
Speech Characteristics of AOS
- AOS is primarily a disorder of articulation and prosody
- the other sub-systems may be impacted as well
AOS (Articulation) 1
- substitutions of one phoneme for another are more common (may be distortions of the target phoneme though)
- placement errors are the most frequent type of substitution error followed by manner, voicing, and oral-nasal errors
- substitution of a voiceless phoneme for a voiced phoneme is more common
- fricatives and affricates are more often in error than stops, nasals, semivowels or vowels
- consonant clusters are more likely to be in error
AOS (Articulation) 2
- initial position deficits are more likely than medial or final consonant positions
- articulation is more accurate on real words than on nonsensical words
- errors are more common on multisyllabic words
- the > the distance b/w articulatory contacts the higher the rate of b/d
—- “puh, puh, puh” vs. “puh, tuh, kuh”; think about AMRs vs. SMRs
- Puh, puh, puh- AMRs and puh,tuh,kuh- SMRs
- errors will be inconsistent during repeated utterances of the same word
AOS (Prosody)
[1] rate of connected speech is slower than normal
[2] equal stress is often placed on all syllables in an utterance
[3] silent pauses may occur at the initiation of a word or b/w syllables; may be the result of articulatory groping
[4] the normal variations in pitch and loudness in an utterances may be reduced
AOS (Respiration)
- some individuals with AOS may not be able to take a deep breath when asked to do so on command
- will demonstrate halting, effortful movements
- this is voluntary; reflexive respiration is not affected by AOS
AOS (Phonation)
- usually phonation is not impacted when the AOS is mild or moderate
- suspected difficulties is really related to the articulation issue where the Pt is struggling for the correct articulator placement
- in severe AOS though, the Pt may be unable to prolong a vowel for both spontaneous and voluntary tasks
— Duffy suggests that this usually occurs in the first 1-2 wks following the onset of the apraxia
Differential Diagnosis (AOS or Aphasia)
[1] does the Pt have pure AOS?; aphasia without AOS?; aphasia and AOS
[2] is the deficit true AOS or a type of paraphasia seen in Pt’s with some aphasias?
[3] is the deficit AOS or just nonfluent language errors associated with a Broca’s aphasia?
AOS therapy basics
- Use of a mirror
- Slow down
- Use easy onset
- Pick words that will give them some success but also challenge them
- Building block towers
- Look at articulation section for Dworkin
