What are the basic structure and function of the Peripheral Nervous System?

and

What is it's relationship to the Central Nervous System?

Perpheral Nerves are composed of BIDIRECTIONAL axon bundles.

-carry sensory and autonomic information to the CNS.

-carry motor information away from the CNS to the muscles

The CNS processes, interprets and integrates information conveyed to it by the PNS

composed of nerves lying outsdie of the CNS

Cranial Nerves = 12 pairs

Spinal Nerves = 31 pairs

1. Peripheral autonomic

2. Spinal

3. Cranial

• Regulates the body's internal enviornment
• Divided into Sympathetic and Parasympathetic-

Sympathetic brach generally arouses body processes to handle perceived emergencies or threats

Parasympathetic branch counteracts the sympathetic branch to relax and calm the body

Through its impact on musular arousal, the Autonomic Nervous System indirectly affects motor-related communicative elements

--e.g. speech fluency, voice

There are 31 Spinal Nerves

-Two "roots" (ventral and dorsal) attach them to the spinal cord

• VENTRAL ROOT is EFFERENT (motor - to the muscles)
• DORSAL ROOT is AFFERENT (sensory - to the CNS)

These fibers conduct impulses from the CNS to control voluntary movment and involuntary processes such as digestion

Speech Realted Cranial Nerves

Nerves      Names                           

V               Trigenminal       

Function:  Face (sensory), jaw (motor)

Symptoms: Facial anesthesia (loss of pain sensation)

      (weakness/difficulty in chewing & controlling mandible 

VII             Facial          

Function: Tongue (sensory), face (motor)

Symptom: 

-paralysis of facial muscles

-reduction in sense of taste

-dry mouth

-difficulty tightly closign mouth

-reduced general facial movement w masklike expression

IX              Glossopharyngeal 

Function: Tongue & Pharynx (sensory), pharynx only (motor)

Symptoms: reduction in taste sensitivity

- reduced gag reflex

-reduced pharyngeal muscle control (possible hypemasality)

X               Vagus

Function: Larynx, respiratory, cardiac, and gastrointestinal systems (sensory and motor)

Sensory: -Dysphagia

-Hoarse voice

-loss of cough reflex

Uni or bilateral paralysis of the vocal folds (devoicing)

XI             Spinal Accesory

Function: Shoulder, arm, throat (motor)

Symptoms: head turning/shoulder shrugging weakness

-reduced pharyngeal and soft palate muscular control 

-possible hypernasality 

XII           Hypoglossal

Function: Tongue (motor)

Symptoms: Atrophy of tongue muscles

-deviation on protrusion 

- fasciculation (tremor)

VIII - Vestibular Acoustic (Vestibulocochlear)

Heairng and Balance (sensory)

Symptoms: Vertigo, dysequillbrium, Nystagmus, Hearing Loss

______________________

Cranial nerves that carry sense information to the brain (afferent) are called "sensory nerves"

Those carrying impulses to the muscles (efferent) are called "motor nerves"

A few called mixed nerves, carry both sensory and motor impulses.

Apraxia is a neuromuscular disorder NOT caused by or related to muscle weakness or paralysis like Dysarthria. 

Apraxia of Speech is characterized by: 

-inaccurate positioning of articulators

-no muscular weakness or paralysis

-inconsistent speech errors 

-normal linguistic (vs speech) function maybe displayed via written modality (reading/writing).

--NOTE however that apraxia often occurs in conjunction with aphasia (a langauge disorder).

It is caused in adults by neuropathology:

model 1: Damage to Central Motor Progamming area (e.g. Broca's area and/or motor cortex)

model 2: damage to phonological processsing areas

-such a view suggests a linguistic rather than an exclusively motor basis for apraxia and is contreversial. 

1. Spastic Dysarthria: is the result of bilateral damage to the upper motor neruons of th pyramidal tract (the motor cortex).

Lesion Site: upper motor neuron

Speech Characteristics include: 

Impercise articulation

monotonuous pitch and loudness

hypernasality

harsh voice quality

poor prosodoy 

slow speech rate 

2. Flaccid Dysarthria is caused by unilateral or bilateral damage to the lower motor neurons.

-lower motor neurons are in the spinal cord

Lesion Site: lower motor neurons

Speech Characteristics include: 

-slow, labored articulation

-combined hypernasal (possible nasal emission) and breathy voice quality

-hoarse/breathy phonation

-monotonous pitch and loudness level 

-Weakness in speech and/or respiratory musculature.

3. Ataxic Dysarthria  

is caused by stroke, tumor, trauma, ataxic cerebral palsy, infection, toxic exposure

-impacted the cerebellum 

Lesion Site: cerebellum and or its connections

Speech Characteristics include: 

-Inaccurate, slow movements

-Hypotonia (general weakness, lack of muscle tone)

4. Hypokinetic Dysarthria  

is generally associated with Parkinson's Disease.

-degeneration of the extrapyramidal system, components that inhibit rapid firing of motor neurons causing uncontrolled movements

Lesion Site: Basal Ganglia and associated brain stem muclei

Speech Characteristics include: 

-Slow movements

-Limited rnge of motion, rigidity 

-Reduced movement automatically 

5. Hyperkinetic Dysarthria  

results in damange from damage to the basal ganglia.

Lesion Site: Basal Ganglia and associated brain stem muclei 

-Two characteristics patterns:

-Movements may be quick, jerky, unsustained, and involuntary.

-When associated athetosis (cerebral palsy_ or dystonia movements tend to be twisting, writing, writhing, tremulous and slow

6. Mixed Dysarthria  

varying combinations of other types

Speech Characteristics include: 

-Slow movements

-Limited rnge of motion, rigidity 

-Reduced movement automatically 

Lesion Site: 

Mixed Flaccid-spastic:  both lower and upper motor neurons (e.g. amyotriphic lateral sclerosis)

Mixed ataxic-spastic-flaccid dysarthria: Cerebellum/cerebellar connections, upper motor neurons and lower motor neurons (i.e. Wilson's Disease)

Dysarthrias have numerous causes: 

Stroke

Degerative Diseases:

e.g. Parkinson's Disease, MS

Infections

-meningitis

Exposure to Toxins

-drug or alchohol abuse

Head Trauma

Cerebral Palsy 

What are the PRIMARY and SECONDARY  characteristics of apraxia of speech?

What are some specific features that differentiate dysarthrias from apraxia of speech?

Primary: errors in articulation 

Secondarily: by what are thought by many to be compensatory alternations of prosody (e.g. pauses, slow rate of speech, eqalization of stress)

Even though both Apraxia and Dysarthria are both motor speech disorders, each represents a breakdown at a different level of speech production. 

Apraxia: on neurological examiniation, show no significant evidence of slowness, weaknwess, incoordination, paralysis

1. Perceptual Assessment

for years this has been a "gold standard" - these assessments are based on the clinicans' impressions of auditory-perceptual attributes of the speech

2. Acoustic Assessment

assessments in this category are based on the study of the generation, transmission, and modification of sound waves emitted from the vocal tract,

3. Physiological Assessment

is based on the concept that assessment of the individual motor subsystems of the speech machanism (i.e. respritory, laryngeal, velopharyngeal, and articulatory subsystems. is crucial in devinind the underlying speech moto pathophysiology neccesary for the development of optimal treatment.

What are the characteristics of perceptual assessment of motor speech disorders?  

What are some advantages and disadvanrtages?

Characteristics:  It is the "gold Standard" and preferred method by which clinicians make differential diagnoses and define treatment programs for their clients with motor speech disorders.

Advantages:  are those that have led to its perferred use as the tool for characterizing and diagnosing dysarthric speech.  Perceptual assessments are reaidly available and require only limited finanical outlay.  All students are taught how to test for and identify perceptual symptoms.  Finally, ,perceptual assessments are useful for monitoring the effects of treatment on speech intelligibility and adequacy of communication.

Disadvantages:

there are a number of inherent inadequacies with perceptual assessment that may limit their use in determining treatment priorities.  First, accurate reliable perceptual judgements are often difficult to acheive, as they can be influenced by a number of factors, inlcuding the skill and experince of the clinician and the sensitivity of the assessment.  In particular, raters must have extensive structured experience in listen prior to performing perceptual ratings.

Second disadvantage:

 perceptual assessments are difficult to standardize in relation to both the patient being rated and the enviornemtnet in which the speech samples are recorded.  Patient variablitiy across over time and acorss different settings preents maintence of adequate intra - and interrater relability.  Futher, the sympmots may be present in certian conditions and not in others.

3rd disadvantage

limits reliance on perceptual assessments is that certain speech synptoms may influence the perception of others.  This confound has een well reported in relation to the perception of resonatory disorders, articulatory deficits and prosodic disturbances.

What techniques are used in acoustic assessment?

Strengths of acoustic assessment

Difference between oscillographic & spectrographic displays when sued for acoustic assessment

usedin conjunction with perceptual assessment to prove complete understanding. it can highly aspects of speech signal that may be contributing to their percetpion of deviant speech production and can provide confirmatory

Strengths:

ossillographic - 2 dimensional- easy to generate and can provide variety

spectrographic - 3 dimensional

Physiological Assessment techniques: is based on the concept that assessment of the individual motor subsystems of the speech machanism (i.e. respiratory, laryngeal, velopharyngeal, and articulatory subsystems) is crucial in defining the underlying speech motor pathophysiology necessary for the development of optiomal treatment programs.

1st step is to determine those components that are malfunctionig and second, the physiological nature and severity of the malfucntion.

Essentially the goal is to evaluate the integrity of speech components (lips, tongue, jaw, velopharynx, larynx, etc.) and systems (articulation, phonation, respiration, etc.) that generate or valve the expiratory airstream.

They use intruments:

eletromyogrphay, kinematic measures, and aerodynamic measures.

What it doesn't have like the others?  Instruments!

1. Compensatory strategies:

utlie remaining strengths and potential

2 Purposefully activity

become more aware of how her articulators work and knteract

3. Early treatment

is essential to begin

4. Monitoring

self-monitering behaviors and behioral change is key strategy in effetively treatmeing

5.  Motivation

better success