Defining Motor Speech Disorders Flashcards
Neurologic process of speech production involves (3):
- Cognitive-Linguistic Process (Aphasia)
- Motor Speech Programming (apraxia)
- Neuromuscular Execution (dysarthria)
Cognitive-Linguistic Process –
the aspect of speech production involving an intention to communicate which is organized into the verbal symbols that follow the rules of language. (Aphasia)
Motor Speech Programming –
the intended communication has to be executed by the neuromuscular system. To do this the speaker selects and organizes the sensorimotor programs that cause the appropriate speech muscles to be activated at the right time. This is the speech programming process. (apraxia)
Neuromuscular Execution –
The CNS and PNS innervate the necessary muscles of respiration, phonation, articulation and resonance to produce desired words. (dysarthria)
Motor Speech Disorders:
Disorders of speech resulting from neurologic impairment affecting the motor programming or neuromuscular execution of speech (2):
- apraxia of speech
- the dysarthrias
Types of Motor Speech Disorders (2)
Dysarthria & Apraxia
Dysarthria:
Collective name for group of motor speech disorders resulting from disturbances in muscular control over the speech mechanism due to damage of the CNS or PNS.
Can result in paralysis, weakness, or incoordination of speech musculature.
Dysarthria can affect which speech subsystems (5)?
All speech subsystems:
- Respiration
- Phonation
- Resonance
- Articulation
- Prosody
Site of lesion for Dysarthria:
CNS
or
PNS
Types of Dysarthria – developed by Darley, Aronson & Brown (6)
- Flaccid
- Spastic
- Ataxic
- Hypokinetic
- Hyperkinetic
- Mixed
Apraxia:
Neurogenic speech disorder resulting from impairment of the capacity to program sensorimotor commands for the positioning and movement of muscles for volitional production of speech.
Occurs in the absence of weakness.
Can apraxia and dysarthria co-occur with aphasia?
Yes, both apraxia and dysarthria can co-occur with aphasia
BUT apraxia more commonly co-occurs with aphasia
Apraxia of speech can affect which subsystems of speech (2)?
- Articulation – may be inconsistent errors (?), difficulty with initiating speech
- Prosody – due to starting and stopping in self-correcting
Does the course of motor speech disorders depends on etiology?
Yes
Course of disease for motor speech disorders (5):
- Transient – symptoms don’t last, they disappear completely
- Improving – things are improving but some symptoms are still there – just not as severe.
- Progressive – symptoms don’t get better, they continue to get worse or new symptoms appear.
- Exacerbating-remitting – symptoms occur, then get better, then occur again; gets worse, then better, etc.
- Stationary – symptoms remain unchanged after they have reached maximum severity.
Treatment of motor speech disorders…
varies depending on type of dysarthria
i.e. for progressive course goals will be different than for developmental or transient
How do symptoms develop for motor speech disorders?(3 types)
- Acute – comes on quickly within minutes
- Subacute – comes on within days
- Chronic – comes on within months
Most motor speech disorders are associated with…
chronic disorders
The Central Nervous System includes:
- Brain
- Cerebrum
- Brain stem
- Cerebellum
- Spinal cord
* areas encased by bone
4 Lobes of the cerebrum:
Frontal lobe
Parietal lobe
Temporal lobe
Occipital lobe
The cerebrum is made up of:
Cortex – outer layer (bark)
Gyri – ridges
Sulci - valleys
The Cerebellum’s job:
Modifing cortical activity
The 3 lobes of the cerebellum are:
- anterior
- posterior
- flocculonodular
- Has 2 hemispheres, right and left
- Vermis – midportion
3 Parts of the brain stem:
Midbrain – links cerebrum to brain stem page 41
Pons – bridges to cerebellum
Medulla – controls respiration
Midbrain (place):
links cerebrum to brain stem
Pons (place):
bridges to cerebellum
Medulla (function):
controls respiration
Are the bones of the skull separated or fused?
Fused -protective device- also hampers at times when expansion needed
4 anatomic levels of the CNS:
- Supratentorial
- Posterior
- Spinal
- Peripheral
Supratentorial level of the CNS:
Made up of anterior & middle fossae
Contains the paired frontal, temporal, parietal & occipital lobes AND basal ganglia, thalamus, hypothalamus & cranial nerves I & II
Posterior level of the CNS:
Made up of posterior fossa
Contains brainstem, cerebellum & cranial nerves III-XII.
Fossae –
3 cavities in base of skull
Fossa – ditch
Foramina
Holes in fossae where cranial nerves exit skull
Where do cranial nerves II-XII originate?
In brain stem at the posterior fossa level
Where do cranial nerves I + II originate?
In the supratentorial level
Cranial nerves important for speech originate at this level, but are part of the PNS.
Are cranial nerves part of the CNS or the PNS?
PNS
but, they originate at the supratentorial (I + II) or Posterior level (III-XII) of the CNS
Spinal level of the CNS:
Spinal cord begins at lower end of medulla, surrounded by bony vertebral column
Spinal cord ends at first lumbar vertebrae.
Peripheral level of the CNS:
12 pairs of cranial nerves
31 pairs of spinal nerves
exit skull through foramina.
Why is it important for speech to have pairs (left + right) of cranial nerves?
Protection
Where do cranial nerves emerge from?
base of brain (brainstem) and penetrate skull through foramina to reach sensory - motor targets
Meninges (covering of the CNS) consist of 3 layers:
- Dura mater-outer membrane -2 layers fused together
- Arachnoid mater - below dura, loosely covers brain
- Pia mater-innermost layer, closely attached to surface of brain
Spaces around the meninges (3):
- Epidural space-between dura and bone
- Subdural space-beneath dura (infection can develop in these 2 spaces due to trauma, blood & pus pool here)
- Subarachnoid space-beneath arachnoid –filled with CSF, connected to inner part of brain via ventricular system
Neurologic Systems (6):
- Ventricular
- Vascular
- Neurochemical systems
- Consciousness system
- Motor system
- Sensory system
Ventricular Neurologic System:
Also called Cerebrospinal system
Ventricles are cavities filled with CSF (cushions brain) produced by choroid plexuses (structures in each ventricle)
Consist mainly of - paired lateral ventricles in each hemisphere, third ventricle between the 2 thalami & 4th ventricle
Vascular Neurologic System:
Involves blood vessels-provides oxygen and nutrients to structures & removes waste.
Brain receives blood from 2 arterial systems, carotid and vertebral basilar system These join at Circle of Willis at base of brain. Vascular disturbances can cause motor speech disorders
Neurochemical systems:
Influences all anatomic levels of nervous system.
Includes amino acids, ACH, neuropeptides, etc.
Consciousness system:
Important for maintaining consciousness, attention & awareness of environment.
Structures involved in this level include those found at supratentorial & posterior fossae level.
Damage can result in motor speech disorders.
Motor system:
Responsible for all motor activity including that of speech.
Includes efferent connection to cortex, basal ganglia, cerebellum, CNS/PNS pathways.
Damage here can cause motor speech disorders.
Sensory system:
Includes peripheral receptor organs
Structural elements of Neurons
- Dendrites
- Axons
- Cell body (soma)
Dendrites:
Transmit sensory information toward the soma