Apraxia of Speech Flashcards
What is apraxia of speech?
“Apraxia is a neurologic speech disorder that reflects an impaired capacity to plan or program sensorimotor commands necessary for directing movements that result in phonetically and prosodically normal speech. It can occur in the absence of physiologic disturbances associated with the dysarthrias and in the absence of disturbance in any component of language.”
Apraxia of speech (AOS) is a problem with
the motor programming of speech movements.
Dysarthria is a problem with
muscles/movement.
Aphasia is a
linguistic/language problem.
In apraxia are the muscles damaged?
No
the muscles are OK.
Does Apraxia involve language?
No
doesn’t involve language unless it co-occurs with aphasia and dysarthria.
*co-occurrence is common
Does Dysarthria or Apraxia co-occur with aphasia more often?
Apraxia co-occurs with aphasia more often than dysarthria
Can Oral or limb apraxia co-occur with apraxia of speech?
Yes
Apraxia of Speech is almost always due to what kind of lesion?
Left cerebral hemisphere damage
* so helps in localization of the lesion
What are the Steps in speaking? (4)
- Speaker conceptualizes what is going to be said. This is where the message is determined.
- Speaker formulates the message through selecting semantic, syntactic, morphological, phonological structures for the message.
- The Motor Speech Programmer programs/plans the movements necessary to produce the needed phonemes. It activates a plan for the motor execution needed.
- This program is sent to through the nervous system to produce muscle movement/motor execution
If difficulties occur in the speaker formulating the message through selecting semantic, syntactic, morphological, phonological structures for the message (step 2), the result may be:
aphasia
If difficulties occur in the Motor Speech Programmer programs/plans the movements necessary to produce the needed phonemes. It activates a plan for the motor execution needed (step 3), the result may be:
apraxia
If difficulties occur with sending the program through the nervous system to produce muscle movement/motor execution (step 4), the result may be:
dysarthria
Other names for Apraxia of Speech (AOS) (2):
- speech apraxia
- oral verbal apraxia.
AOS vs Broca’a aphasia:
1 AOS is sometimes confused with Broca’s aphasia because the phonologic impairment seen in Broca’s aphasia may be similar to AOS.
2 Broca’s aphasia may include AOS but involves more than AOS.
3 Individuals with AOS do not have linguistic problems that are seen in Broca’s aphasia.
4 The two have similar sites of lesion.
5 Probably some of the speech problems people with Broca’s aphasia have are due to MSP problems and not always linguistic problems
Why do you need to always assess for both Aphasia and Apraxia?
Because aphasia and apraxia so often co-occur, always evaluate for both in a client suspected of one or the other.
ANATOMY AND BASIC FUNCTIONS OF THE MOTOR SPEECH PROGRAMMER
- The Motor Speech Programmer (MSP) is considered to be responsible for programming speech.
- It transforms the abstract phonemes to a neural code from which the motor programming can occur.
- This neural code determines the specific muscle movements needed.
- It is theorized that the motor speech plans are prepared before the muscle movement begins and that they are held in a buffer area. These plans can be modified before movement begins or during movement. This pre-planning is thought to be what allows us to have rapid speech.
- You have to have linguistic input in order to know what to organize. This linguistic input to the MSP comes mainly from the perisylvian area in the left hemisphere. This includes the temporoparietal cortex, the insula, and the basal ganglia and thalamus.
Some of the specifics of the programming possibly include (we don’t know for sure) (6):
- Duration of movement
- Amplitude of movement
- Acceleration
- Deceleration
- Time to peak velocity
- Timing of speech events.
Where is the MSP thought to be located?
In the left cerebral hemisphere.
It is a theoretical system that involves several interacting structures and pathways in the left cerebrum.
These structures are primarily located in the parietal-frontal and related subcortical circuits.
The insula:
- is a cortical brain area that is buried within the lateral (sylvan) cerebral fissure.
- It is hidden in the folds and can’t be seen unless you separate the temporal and frontal lobes.
(However the latest research done by Dr. Robin and Dr. Wambaugh indicate that the insula might not be involved in apraxia.)
- The insula (?) is an important area in apraxia in that it is a frequent site of lesion for people with apraxia. It can be the only site of lesion but apraxia can occur without lesions in the insula. (Note that this has recently been questioned.)
Specifically the following areas are thought to be primarily involved with the MSP (4):
1 Premotor area (see page 46 figure)
2 Parietal lobe somatosensory cortex and supramarginal gyrus
3 The insula (?)
4 The basal ganglia
Dr. Don Robin (RIC-UTHSC) has found that Brodman’s area 6:
- is an important area in apraxia and that damage in that area is associated with apraxia
Premotor area (see page 46 figure):
o In the Pre-motor area, Broca’s area is especially important for apraxia. People with apraxia are most often found to have lesions in Broca’s area.
o Supplemental motor area is not a common site of lesion for apraxia but may be sometimes involved.
o The premotor areas are linked to the basal ganglia and cerebellar circuits for input. They also send connections to the motor area for impulses to be sent on and put into place by the Motor Speech Program.
Parietal lobe somatosensory cortex and supramarginal gyrus:
are important in integrating sensory information that is needed for skilled motor activity.