Lesson 18: Neuropathology of Communication Disoders Flashcards Preview

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Flashcards in Lesson 18: Neuropathology of Communication Disoders Deck (51)
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1
Q

What type of nerves are peripheral nerves that innervate the trunk and limbs?
What does this mean?

A

Mixed nerves
They carry the axons of both sensory and motor neurons. The cell body of the motor neuron is situated in the spinal cord, but the entire neuron is considered a peripheral neuron.

2
Q

To complete a reflex, where does a sensory neuron have its cell body, where does it synapse?

A

Has its cell body in the dorsal root ganglion, but reaches into the spinal cord to synapse on the next neuron in its pathway, or on an interneuron, or directly on the motor neuron to complete a reflex

3
Q

What is a monosynaptic reflex?

What type of neuron could it be from cranial nerves?

A

When the sensory neuron synapses directly on the motor neuron without involving an intervening interneuron
May be motor, or sensory, or both, and may have associated parasympathetic supply

4
Q

If a lesion is very close to the spinal cord, what roots does it affect?

A

Motor or sensory

5
Q

Where are somatic peripheral nerve injuries, and what type of loss is there?

A

Distal on the nerve and produce mixed motor and sensory loss

6
Q

In their course, what kind can cranial nerves be?

A

May be motor, sensory, or both

7
Q

What disease is the failure at the nerve-muscle interface (neuromuscular junction)? What is the deficit?
What is the treatment involved?
What is the presenting sign?

A
  • Myasthenia Gravis, an autoimmune destruction of acetylcholine receptors
  • Administration of acteylcholinesterase inhibitor to prolong the presence of the neurotransmitter in the synapse
  • “weakness” is the presenting sign, it differs fundamentally from other forms of weakness in its mechanism (e.g., from an UMNL).
8
Q

What is the strategy used in treating Myasthenia Gravis?

A

Focus of treatment is frequently on energy conservation and budgeting. For example, avoiding back-to-back long conversations and managing timing of speech tasks throughout the day are common strategies to maximize clarity of speech and prevent exhausting the respiratory muscles for clients

9
Q

What is an infection which causes injury to the cell body?

What type of lesion does this produce? Why?

A

Polio is a viral infection, which selectively damages the alpha motor neuron cell body
- Produces a lower motor neuron lesion because it damages the “final common pathway” at the spinal cord, including local reflexes and instructions from both the pyramidal and extrapyramidal tracts.

10
Q

With an infection like polio, what is the difference if there is damage close to the cell body, vs. away from the cell body?

A
  • If the lesion is close enough to the cell body, the neuron’s source of repair activity will be destroyed and regeneration will not occur.
  • If the damage is some distance from the cell body, there will be a continuous effort on the part of the cell to regrow the lost limb (axon)
11
Q

If there is an injury to a peripheral nerve what will be the resulting impairment in comparison to the lesion?
Is regeneration possible?

A
  • Injury to a peripheral nerve (somatic or cranial) will result in impairment ipsilateral to the lesion
  • Regeneration is usually incomplete, but possible.
12
Q

With peripheral nerve lesions, what has to happen before sensory and motor activity can occur?
What happens if there is a CNS lesion?

A
  • The reflex arc is interrupted and not sensory or motor activity can occur until regeneration is complete
  • If there is a CNS lesion, this unit IS intact and may function in spite of loss of its modulation by higher centres
13
Q

What are common examples of lesions to the peripheral nerves?

A
  • Facial nerve palsy due to compression in the facial canal
  • Sensory loss due to lesions of branches of the trigeminal nerve from skull fracture
  • Motor and sensory impairments due to lacerations or surgical procedures
14
Q

In a peripheral nerve lesion, is the nerve sheath is intact, what is there potential for?

A

Spontaneous regeneration

15
Q

What is the difference between CNS and PNS lesions in terms of complexity?

A

Nerve injuries in the nervous system tend to be isolated to single nerve branches, unlike central nervous system lesions, which are more complex

16
Q

What is an example of a peripheral nerve lesion that involves speech?

A

Stretching of the left phrenic nerve with an enlarged heart

17
Q

Classification of trauma to peripheral nerve:
What are the 3 different classes of PN injury?
Potential for recovery?
Rate of repair?

A

Neuropraxia – transient block only – recovers
Axonotmesis – axon damaged, sheath intact – recovery likely
Neurotmesis – axon and sheath disruption – requires surgery

18
Q

How much does Wallerian degeneration and regeneration take?

A

1mm/day

19
Q

What does damage to a peripheral nerve innervating muscles of speech?

A

Will produce a dysarthria (flaccid dysarthria in this case)

20
Q

What does a LMNL involving muscles of speech always produce?

A

Produces a dysarthria but not all dysarthrias are LMNLs

21
Q

What is a disease involved with mixed peripheral and central nervous system damage?
What are the symptoms?

A
  • ALS involves damage to motor tracts and nuclei including both somatic and cranial nerves. (UMNL and LMNL)
  • It affects the ability to breathe and swallow, often producing choking. It also includes motor impairment of the limbs, especially the upper limbs and neck
22
Q

What muscles do the sympathetic and parasympathetic nervous systems innervate?
What do the systems do?

A

Innervate smooth muscle, cardiac muscles and glands
- Systems are in balance, usually innervating the same structures, to maintain homeostasis (parasympathetic) and regulate responses to threats (sympathetic).

23
Q

Where can Horner’s syndrome occur?

A

Within spinal cord or into the head, neck, trunk and limbs.
- These nerves travel along the peripheral nerves, then travel on blood vessels to supply the blood vessels (smooth muscles), cardiac muscles and glands.

24
Q

What are the symptoms that present with lesions of the sympathetic nervous system?

A

Present as an unopposed action of the parasympathetic system with which it is normally in balance

25
Q

What are the symptoms of Horner’s syndrome?

A
  • Droopy eyelid because the eyelid is innervated by both the oculomotor nerve (voluntary) and the sympathetic to smooth muscle
  • Pupil constricted (due to unopposed action of constrictor pupillae)
  • A dry, red face (dry = loss of sweating for cooling; red = loss of usual blood shunting to muscles).
26
Q

What do traumatic brain injuries involve?

A

Direct damage to brain tissue and may include injury to blood vessel, complicating the problem with ischemia to areas involved and downstream as well. In addition, bleeding may produce a space-occupying lesion

27
Q

What are examples of space-occupying lesions caused by bleeding?

A

Subarachnoid, epidural, and subdural hemorrhages

28
Q

What are examples of brain injuries and consequences of neck injuries?

A

Brain: damage to the brainstem, which can occur in severe whiplash, with damage to the vestibular system and cranial nerves.
Neck injuries: damage to the vertebral artery, which may result in clots, vessel collapse, or rupture. This occurs with trauma of boxing and shaken baby syndrome as well as general brain trauma from falls, automobile accidents etc

29
Q

What is multiple sclerosis?

What does it damage?

A
  • Due to demyelination within the CNS

- Damage to motor supply of speech centres and trunk and limbs produce dysarthria and motor weakness

30
Q

In motor control disorders, what type of lesions can occur? Which side are they involved?

A

Lesions of the cerebellum result from strokes, trauma and tumours. These lesions involve the trunk and limbs on the SAME side of the lesion

31
Q

In lesions of the cerebellum, what is involved, and which 3 structures?

A

Involves changes in quality of movement showing lack of quality of movement in terms of vestibular function (archicerebellum), synergy and postural control (paleocerebellum), and fine coordination (neocerebellum)

32
Q

What do lesions in the basal ganglia involve?

What are the three basal ganglia disorders?

A

Involve changes in patterning of movement (quality) but do not cause paralysis
Parkinson’s: loss of secretion of dopamine from substantia nigra cells into the lentiform and caudate nuclei
Hemiballismus/hemiballism: damage to subthalamus
Huntington’s disease: loss of neurotransmitters in the caudate and lentiform nuclei – notably GABA

33
Q

With space-occupying lesions, what happens if the lesions occur slower?

A

The more likely they are to accommodate and the more likely recovery is possible

34
Q

Which side of the brain are language functions controlled?

A

Controlled by the dominant hemisphere (left brain dominance is the most common)

35
Q

What part of the brain is body awareness and spatial organization controlled?

A

By the non-dominant hemisphere in the parietal lobe

36
Q

In the lesioned area of the posterior limb of the internal capsule, where do motor and sensory fibres travel?

A

Motor and sensory fibres, passing from the motor areas in the frontal lobe and to the sensory cortex in the parietal lobe, ALL pass through here

37
Q

When is the only time that a stroke involving cerebral arteries can involve motor and sensory involvement in both upper and lower limbs at the same time is…?

A

Is to occur in the internal capsule.

38
Q

What structures are involved in peripheral and central lesions in the auditory nerve?

A

The auditory pathway, the primary auditory cortex and the association cortex, including the Wernicke’s area.

39
Q

What is Broca’s aphasia?

A

Inability to express language due to damage in Broca’s area in the frontal lobe in the dominant hemisphere (left brain) areas 44 and 45, with relatively preserved comprehension.

40
Q

What is Wernicke’s aphasia?

A

Inability to comprehend spoken language – usually involves poor insight, fluent but non-meaningful expression – areas 22 and 39. Global aphasia: Severe impairments in both expression and comprehension due to a large area of damaged to the area supplied by the middle cerebral artery, expansive enough to block branches to the frontal and parietal lobes

41
Q

What is apraxia of speech?

A

Inability to carry out voluntary actions of vocal apparatus in the absence of paralysis (may have involuntary [automatic] speech). Involves damage close to Broca’s area.

42
Q

What is dysarthria and dysphagia?

A

Upper and/or lower motor neuron problems involving voluntary motor activity of cranial nerves involved in speech generation and swallowing

43
Q

What are signs of lower motor neuron lesions?

A

Loss of voluntary movement
Flaccid paralysis
Hypo or atonia, areflexia
Rapid muscle wasting (atrophy)

44
Q

What do spinal cord lesions from fractures above the lumbar vertebra result in?
What do lower levels of injury result in?

A
  • Loss of all voluntary motor function below the lesion

- Mixed upper and lower motor neuron lesions.

45
Q

How is Parkinson’s caused?

A

Lack of cells in substantia nigra; no dopamine secreted into lentiform and caudate areas

46
Q

What are the symptoms of Parkinson’s?

A
Resting tremor (facial muscles)
Slowness to “change motor set”, meaning the pattern is slow to change
Speech is slow to initiate, but gets started, blurts out and speeds up, then with loss of volume from respiratory muscles, decline such that speech is slow and monotonous (referred to as “hypokinetic dysarthria”). 
The individual’s posture is flexed with a shuffling gait. Dysarthria, dysphagia, and in many cases, cognitive impairment occur
47
Q

How is Huntington’s Chorea caused?

A

Hereditary damage in the caudate area

48
Q

What are symptoms of Huntington’s?

A

Movement is choreoform (a series of rapid, repeated jerky, coarse movement, in a pattern that is not typical nor repeated, but always changing).
Speech is similar in motor pattern: jerky, blurting out, and inconsistent and unpredictable. Cognitive impairment and dementia often occur

49
Q

Where do lesions of the cerebellum alter motor function in limbs?

A

Limbs ipsilateral to the lesion (uncrossed afferent pathways and uncrossed efferent pathways)

50
Q

Where do lesions of the basal ganglia and cortex, like the thalamus, alter the spinal motor function in limbs?

A

Contralateral to the lesion (but many basal ganglia lesions are commonly bilateral, so both sides are affected, although usually one is worse than the other)

51
Q

Where is the CNS input to cranial nerve efferent nuclei?

What are the exceptions?

A

Usually bilateral but predominantly contralateral
- Lower face, crossed only – no backup; the muscle that we test with tongue protrusion is crossed; trochlear nerve crosses after it leaves brainstem, therefore the nucleus is contralateral to the muscle supplied

**Any lesion is likely to be damaged on the way to the eye and therefore the lesion would still be ipsilateral to the muscle supplied