MSD Quiz 1

Speech is a

complex motor act

generates multimodal feedback more than any other routine motor behavior

Motor speech disorder

impairment caused by lesion or dysfunction of motor speech centers in PNS, CNS, or both. resulting in inability to regulate movements required for speech.

Motor speech disorders are speech disorders resulting from…

neuro impairments affecting planning, programming, and control or execution of speech.

MSDs may be

congenital or acquired

static, improving, degenerative

associated in lesions of various CNS or PNS structures

caused by numerous diseases'/conditions

Paresis

partial or incomplete paralysis

plegia

paralysis

Monoparesis/monoplegia

weakness/paralysis of one limb

hemiparesis/hemiplegia

weakness/paralysis of one side of body

Paraparesis/paraplegia

weakness/paralysis of both lower extremities

Quadriparesis/quadriplegia

weakness/paralysis of all 4 limbs

Anarthria

extreme form of dysarthria

Terms referring to childhood MSDs

Childhood dysarthria (CD)

Developmental verbal dyspraxia (DVD)

Childhood apraxia of speech (CAS)

Dysarthria

reflects abnormalities in strength, speed, steadiness, tone, accuracy of movements required for breathing, phonation, resonation, articulation, prosody of speech

each type has different auditory perceptual characteristics

accurate identification has implications for localization and medical diagnosis, provides cues for diagnosis/management/treatment

Diagnosis of dysarthria

made by neurologist and SLP

symptoms should coincide with neuro diagnosis

can affect any of speech production subsystems

abnormal movement described subjectively by SLP

Causes of dysarthria

CVA, TBI, brain tumor, conditions that cause facial paralysis or weakness, degenerative disorders, pharmacological agents (sedatives, narcotics)

Clinical challenges diagnosing dysarthria in children

must be differentiated from other conditions that cause dev. communication disorders

Clinical challenges diagnosing dysarthria in adults

must be differentiated from AOS, lang deficits, cog deficits

Flaccid dysarthria

Location: LMN- Myasthenia Gravis

Primary Deficit: Weakness

Spastic dysarthria

Location: UMN- unilateral

Primary Deficit: Spasticity

Ataxic Dysarthria

Location: Cerebellar control circuit- Friedrich’s ataxia

Primary Deficit: Incoordination

Hypokinetic dysarthria

Location: Basal ganglia control circuit- Parkinson’s disease

Primary Deficit: Rigidity, decreased ROM

Hyperkinetic dysarthria

Location: Basal ganglia control circuit-Huntington disease

Primary Deficit: Involuntary movements

Unilateral UMN dysarthria

Location: Unilateral UMN

Primary Deficit: Weakness, incoordination, spasticity

Mixed dysarthria

Location: more than 1- ALS

Primary Deficit: More than 1

Apraxia

disruption in ability to voluntarily sequence complex movements accurately

problem sequencing steps of complex movement that have been planned by higher brain centers

Not result of muscle weakness or decreased ROM

Oral apraxia

problems doing nonverbal movements on command

hesitations, groping, revisions displayed when attempting to perform nonverbal movements

may or may not coexist with AOS

sometimes referred to as buccofacial apraxia in adults

Apraxia of speech

disruption of sequencing voluntary movements for speech production

groping, schwa at end, can do things reflexively not on command

errors of sequencing when saying multisyllabic words

automatic and emotional words are free of errors

Apraxia in children

impaired ability to execute voluntarily the expected motoric and programing gestures required for speech in absence of muscular disturbance of speech mech

Apraxia in adults

disorder of artic and prosody

aphasia and dysarthria may coexist but muscle strength and endurance deficits don’t account for errors

errors are inconsistent, trial+error responses are prevelant

Mild apraxia

individual artic gestures are largely preserved

Moderate apraxia

automaticity of coartic will be impaired

Severe apraxia

impairment of ability to position articulators time after time

Psycholinguistic stage and description- Ideational level

generation of thoughts and desire to express them

Psycholinguistic stage and description- language planning level

semantic-syntactic knowledge is activated

Psycholinguistic stage and description- motor planning level

specific phonemes are selected

Psycholinguistic stage and description- motor programming

selected phonemes transformed into neuromuscular commands

Psycholinguistic stage and description- execution

movement of articulators

Psycholinguistic theory of speech motor control

not concerned with site of lesion

shows psychological process that underlie speech processing

early stage of model described as co-linguistic

planning+programming early in speech processing

motor execution at later stage

apraxia- disorder of planning+programming

Dysarthria- disorder of execution

Neurological model

places verbal apraxia disturbances at higher-level of cerebral functioning

lesions that cause AOS are highest level of motor integration

lesions in adults with AOS are left hemi

dysarthria is more peripheral

Dysarthria is result of disturbances in lower level motor integration

Social perspective of MSDs

MSDs associated with long-term conditions

model of the consequences of chronic disorder is helpful in clinical perspective

Social model of disability and dysarthria

developed by the disabled people based on their own experience

Social model of disability

impairment-functional limitation within the individual caused by physical, mental, or sensory impairment

Disability- loss or limitation of opportunities to take part in “normal” life on equal level due to physical/social barriers

Nature of barriers: info, peer support, housing, technical aids, personal assistance, transportation+mobility access

There may be additional barriers to those with MSDs

Time barriers

not allowing enough time for person to express themselves

Time to be scheduled that enable to participate

Organizational barriers

time for equality and ease in communication

allowing time to fully listen

use variety of communication aids/techniques

Identity+Self Expression Barriers

expressing ones own sense of self-dev. through interpersonal experiences

sense of self is constructed through interactions with others

Dysarthric speech introduces inequality in interaction process

Typical speech can gain dominance

Personal Experiences

Deep internal frustration

Effects on Working Lives

Acceptance of AAC

limitations regarding job performance

Motor control system

speech system composed of sensory and motor regulators

cog, lang, and neural reps are not the emphasis

theoretical basis of Notsell’s view derived from discussions that contrast primate and human oral mech

reflexes, values, oscillators combine to produce speech

different mech control speech and feeding movements

practice needed to activate specialized neuronal connections that control fine motor speech movements

Motor Control System therapeutic implications

clinical approach based on how regulators evolved for speech purposes

speech system viewed as finite set of interconnected functional unites capable of fine motor movements

movements manifested by performance in strength, endurance, ROM, speech

Goal of SLP to evaluate functional resources of each component of speech system

Respiratory subsystem

speech production requires airflow

pulmonary airstream mech; pushes air out of lungs through trachea to produce airflow

ingressive-inhalation

egressive-exhalation

Exhalation cycle- needs to be extended in time (for completion of utterance) and modulation(to reflect stress)

Phonatory Subsystem

vocal production+intonation

includes various muscles and structures in larynx, regulates production of voice and intonational aspects

VF adduct and airflow builds up (subglottal pressure) to set VF into vibration(undulation)

VF are stretched lengthwise to manipulate frequency or pitch

Resonatory System

regulates vibration of the airflow as it moves from pharynx into oral and nasal cavity

manipulates shape and size of vocal tract for maintaining normal sound quality

manipulates velopharyngeal port for determining nasality of sounds

• oral vs nasal sounds

Articulatory subsystem

controls articulators to manipulate airflow

major structures: lower jaw, lips, tongue

Tongue: intrinsic muscles (fine tuned movements) and extrinsic muscles (coarse movements)

• protrusion, retraction, elevation, depression

muscles contract to create constrictions in oral cavity to produce varying sounds

Perceptual Measures

Perceptual judgement of intelligibility, accuracy, and speech production

Acoustic measures

visual rep of speech sound wave (spectogram) for more detailed and objective view of speec

Physiological measures

measurement of physiologic aspects of speech motor system not easily perceived otherwise (muscle strength)

CNS

brain and spinal cord

center of integration and control

PNS

nervous system outside of brain and spinal cord

consists of: 12 cranial nerves (carry info to and from brain), 31 spinal nerves (carry info to and from spinal cord)

The brain

most complex part of nervous system

all nervous system activity originates in or processed by brain

composed by wrinkled, pinkish gray tissue

Surface anatomy of brain includes

cerebrum-composed cerebral hemispheres

cerebellum

brain stem

Cerebrum

largest most conspicuous portion of brain

2 hemispheres connected by corpus collosum (goes front to back)

outer cortex of grey matter surrounding interior white matter

surface marked by ridges called gyri+ separated by grooves called sulci

Cerebral Cortex

Cortex- superficial gray matter; accounts for 40% of brain mass

• consists of neuron cell bodies, dendrites, unmyelinated axons, no fiber tracts

Conscious mind

it enables sensation, communication, memory, understanding, voluntary movements

hemispheres are not equal in function

Lobes of the cerebrum

four lobes- parietal, frontal, temporal, occipital

Central sulcus- separates frontal and parietal

Precentral gyrus- primary motor area

Postcentral gyrus- primary somatosensory area

Deep sulci divide hemispheres into 4 lobes

Motor areas

control voluntary movement

Sensory areas

conscious awareness of sensation

Association areas

intergrate diverse info

Primary cortex 4 areas

primary auditory cortex

primary visual cortex

primary sensory cortex

primary motor cortex

Primary motor cortex

location: frontal lobe anterior to central sulcus

Contains motor neurons that send axons to skeletal muscles

Function: initiation and coordination of movements for fine motor skills,postural coordination

3 areas in frontal lobe involved in motor movement

Primary motor cortex

premotor cortex

supplemental motor area

Association cortex

any of the expanses of cerebral cortex that aren’t sensory or motor but are associated with advanced stages of sensory info processing, multisensory integration, or sensorimotor integration

Areas: temporal, frontal, parietal, visual

Cortical level

contains sensory and motor areas that are critical to normal voluntary movements

Functional stages:

• Motor planning, motor programming, motor execution

Layer of nervous system containing primary motor cortex, premotor cortex, supplementary area, brocas area

Motor areas of speech

Premotor cortex

Primary motor area

Supplementary motor area

Broca’s speech area

Premotor cortex

memory bank for skilled motor activities already learned

anterior to primary motor cortex

involved in learned or patterned skills

involved in planned movements

Function:

• organization of movements before they’re initiated

• rhythmic coordination during movement

  • Enables transition between sequential movements of a serial motor skill

  • control of movement based on observation of another person’s performing a skill

Supplementary Motor area

involved in preprogramming movement sequences already in motor memory

medial surface of frontal lobe adjacent to portions of primary motor cortex

functions include involvement in control of sequential movements, preparation and organization of movement

Broca’s speech area

Motor speech area that directs muscles of artic

located in inferior frontal gyrus of frontal lobe

vocalization program is formed and transmitted to muscles of face, tongue, VF, pharynx to form speech

Organization of primary motor cortex

Location: posterior part of frontal love

allows conscious control of precise, skilled, and voluntary movements

entire body is represented

mapping of motor areas

• located in precentral gyrus of frontal lobe

• more cortical area devoted for muscles involved in skilled, complex, delicate movements

Received motor impulses that have been processed by subcortex (nuclei and thalamus) and cerebellum

long axons extend from cortex to lower end of spinal cord

• axons make up direct and pyramidal motor system

Brain Stem

3 regions: midbrain, pons, medulla obongata

controls automatic behaviors necessary for survival ex) breathing, BP, sleep, walking, balance, swallowing, vomiting

Provides pathway for tracts between higher and lower neuro centers

associated with 10 of 12 cranial nerve pairs

Midbrain

Visual and auditory reflexes

orienting references

cerebreal peduncles- 2 buldging structures with descending motor tracts

substantia nigra- large areas with dark pigment, helps subconscious muscle activity, loss of neurons here=PD

Red nucleus- help control voluntary movements of limbs

Pons

relay info from cochlea and vistubular apparatus

control of movement and sensations for face

Fibers of the pons: connect higher brain centers and lower centers, relay impulses between motor cortex and cerebellum

Medulla oblongata

integration of breathing and swallowing

control of respiration, BP, coritcal arousal

cardiovascular control center- adjusts force and rate of heart contraction and blood vessel diameter to regulate BP

Respiratory center- along with pons, controls rate and depth of breathing

Other centers- regulate vomiting, hicupping, swallowing, coughing sneezing

Cranial nerves IX-XII

Most inferior part of brain stem

pyramids- 2 longitudinal ridges formed by corticospinal tracts

decussation of pyramids crossover points of corticospinal tract

Cerebellum

Regulates muscle tone and balance, coordinates movement

2nd largest region of brain, 10% of brain volume, 50% of brain neurons here

2 primary functions:

• adjusting postural muscles- coordinates rapid, automatic adjustments that maintain balance and equilibrium

• programming and functioning movements controlled at subconscious and conscious level

Subcortical Grey Matter includes

basal nuclei

substantia nigra

thalamus

Basal nuclei made up of… and helps…

Caudate nucleus

putomen

gloubus pallidus

striatum

helps initiate and terminate movements, suppress unwanted movements, regulate muscle tone

Thalamus

transmits to and from cortical areas

large mass of subcortical gray matter, one on either side of midline

relays to cerebral cortex, receives from diverse brain regions

Nervous system cells

neurons

cell body

dendrites

axons

myelin

Neuronal communication- action potential

neural impulses, brief electrical charge that travels down an axon

generated by movement of positively charged atoms in and out of channels in axons membrance

Neuronal communication- threshold

level of stimulation required to trigger neural impulses

Neuronal communication- synapse

junction between axon tip of sending neuron and dendrite of cell body of receiving neuron

tiny gap is called synaptic gap or cleft

Neuronal communication- neurotransmitters

chemical messengers that transverse synaptic gaps between neurons

travel across synapse and bind to receptor sites on receiving neuron influencing whether it will generate a neural impulse

The nerve

basic component of nervous system

cell structure:

• cell body- contains nucleus

• dendrites- receives info from other cells

• axon- extensions from cell body, one per neuron, sends info from neuron

Nerves

neural cables containing many axons

part of PNS

connect CNS with muscles, glands, sense organs

Tracts

bundles of functionally related axons tracts

part of CNS- bundle of motor axons that travel from cortex to spinal cord(corticospinal tract)

Descending motor pathways

Direct motor system(pyramidal system)

• corticobulbar tract

• corticospinal tract

Indirect (extrapyrimidal system)

• Subcortical level (basal nuclei)

• Descending pathways

Layers of nervous system

cortical level

descending motor pathways

cerebellar level

Peripheral level

Direct motor system (pyramidal system)

Controls: muscle tone, conscious skilled movements in face and distal limbs

Directly synapses with LMN in brainstem or spinal cord

tracts include corticobulbar and corticospinal

operates at conscious level

originates in cerebral cortex

initiates movement from premotor and prefrontal area that are receiving sensory info from other areas of brain

control contra lateral side of body

Corticobulbar tract (head and neck)

descend through subcortex and brainstem to connect with the cranial nerves that control oral mech

courses through internal capsule then cerebral peduncles, mixed with fibers in the pons then on ventral surface of medulla in medullary pyramids

important in speech production

descends with corticospinal tract to midbrain in brainstem where they diverge

doesn’t go beyond medulla’s inferior bulb where CNs attach

influences action of motor of the CNs that innervate oral musculature

Corticospinal tract (below the head)

arises from various sensory motor areas

descends and enter diencephalon where fibers decussate at opposite side

axons of UMN

• descend through internal capsules and cerebral peduncles to pyramids of medulla oblongata

75% decussate and descend in lateral corticospinal tract, other become ventral corticospinal

• supply all levels of body

• Remaining fibers descend uncrossed in anterior corticospinal

supply neck and upper limbs

neurons terminate on motor neurons in grey matter of spinal cord

starts in layer 5 of primary motor cortex

controls fine movements

What can happen if there is destruction to corticospinal tract

loss of muscle strength, decreased dexterity of hands and fingers

Indirect Pathway (extrapyramidal)

compexecution of subconscious motor programs

helps maintain appropriate level of skeletal muscular tone

includes basal nuclei and 4 descending pathways that originate in brainstem

Subthalamic nucleus

Substantia nigra

includes 4 tracts

complex and regulates: balance, posture, coarse movements of proximal portions of lumbs, head/eye/neck movement

involves movement not willed: akensia, dyskiniesea, rigidity, PD, chorea, athetosis

Indirect pathway includes what tracts

Rubrospinal

vestibulospinal

reticulospinal

tectospinal