voice lecture part of 5

Question 1

• the lateral convexity of the cerebral cortex is involved in vocalization (Larson, 1988)
• Stimulation of the precentral gyrus in either hemisphere and stimulation of supplementary motor cortex, elicits vocalization (Penfield & Roberts, 1959)
• Connections between precentral gyrus and the nucleus ambiguous – subcortical site of the laryngeal motoneurons-
• Laryngeal muscles are thus coordinated with other articulators for precise timing of voice onset

Answer 1

cerebral cortex

Question 2

what are the subcortical mechanisms?

Answer 2

• limbic and diencephalic structures

- basal ganglia and extrapyramidial system

Question 3

• seem to be implicated in animal studies of vocalization (Larson 1988)
• the anterior cingulate gyrus; hypothalamus, bed nucleus of stria terminalis, nucleus accumbens; and septum, midline thalamus; amygdala; and zone incerta have been electronically stimulated and vocalization has occurred.
• been noted that periaqueductal gray matter is the lowest part of the brain that may be stimulated electrically to elicit vocalization. Mutism may result if these cells are destroyed.

Answer 3

limbic and diencephalic structures

Question 4

have been noted to be involved in vocalization—certain types of incidents involving the midline thalamus lead to hypophonia and dysarthria ( Meissner, Sapir, Kokomen, and Stein (1987); also it has been shown that other diseases such as Huntington’s Disease or type of palsy also affect vocalization

Answer 4

basal ganglia and extrapyramidial system

Question 5

serve the respiratory mechanism

Answer 5

cervical plexus and brachial plexus

Question 6

communicates with the vagus (X); hypoglossal (XII) and spinal accessory (XI) cranial nerves

Answer 6

cervical plexus

Question 7

supplies nerves to the upper limbs

Answer 7

brachial plexus

Question 8

is influenced by thoracic intercostal nerves and also phrenic nerve of the cervical plexus

Answer 8

diaphragm

Question 9

nerves that innervate the ____ come from the recurrent laryngeal branch of the vagus from the sympathetic thoracoabdominal nerve trunks connecting with the thoracic and upper lumbar segments of the spinal cord

Answer 9

sensory nerves of trachea

Question 10

may be sensory, motor or mixed; The Vagus- is both sensory and motor in function

Answer 10

cranial nerves

Question 11

include locations in the pharynx, larynx, external ear, thorax, abdominal cavity, heart and lungs.

Answer 11

sensory receptors

Question 12

involved in respiratory, cardiovascular, as well as digestive sensations. Motor control include innervation of the palatal muscles; pharyngeal muscles and all intrinsic laryngeal muscles

Answer 12

vagus

Question 13

1.superior laryngeal nerve 2.the recurrent or interior laryngeal nerve

Answer 13

two large divisions of the vagus

Question 14

: innervates the cricothyroid muscle of the larynx. The external branch of the superior laryngeal nerve of the vagus innervates the intrinsic laryngeal muscles responsible for pitch control and also innervates the inferior constrictor muscle

Answer 14

superior laryngeal nerve

Question 15

All of the intrinsic muscles of the larynx except the cricothyroid, are innervated on each side by the recurrent nerve.

Answer 15

recurrent laryngeal nerve

Question 16

a thickening of the vagus near the brainstem which all fibers innervating the vocal tract are present

Answer 16

nodose ganglion

Question 17

Changes to Peripheral Nervous System : denervation atrophy in skeletal muscles, decreased contractile strength in muscles; decreased number of motor neurons, slowing of reception of neurotransmitter at the neuromuscular joint; degeneration of the cricoarytenoid muscle in mid adulthood; degeneration of the thyroarytenoid , interarytenoid, and cricoarytenoid muscles; slower speaking rate; reductions in nerve supply to muscles of speech mechanism; degeneration of nerve fibers

Answer 17

linville 2000

potential effects of aging on voice

Question 18

Changes to the Central Nervous System: brain atrophy; loss of white matter after age 50; less brain weight; loss of nerve cells in frontal lobes between 45 and 83; slowing of motor planning; decline in dopamine levels, leading to decreased muscle tone, and lowered motor performance and sensorimotor integration; slowing of all sensorimotor processes including speech production; degeneration of neurotransmitter, leading to slower speech; slowing of the swallow function leading to increased bolus transit times

Answer 18

linville 2001

potential effects of aging on voice

Question 19

results from the creation of a vibrating column of air. Oscillation of the vocal folds depend on certain “biophysical conditions” that is necessary for phonation.

Answer 19

phonation

Question 20

what are the biophysical conditions of phonation

Answer 20

o glottal configuration: vocal fold size; shape and approximation
o aerodynamic changes in airflow and surface pressures
o changes in tension of the vocal folds
o changes in elasticity, density and viscosity of structures

Question 21

Degree of adduction influences quality of phonation.
Deviations of in laryngeal approximation; and resistance may be so great that aerodynamic process needed to set the folds in motion are beyond respiration system capability. This may occur when folds are not adducted enough or when they are adducted too tightly.

Answer 21

nuerological aspect cont.

Question 22

• may range from absence of vocal fold adduction to partial adductions; possibly due to brainstem injury.
  
  • vocal fold paralysis or paresis (weakness) may be unilateral or bilateral
  • may be due to adductor muscle damage or recurrent laryngeal nerve damage- branch of Vagus (Xth cranial nerve

Answer 22

nuerological deficits/inappropriate adduction patterns during intentional phonation

Question 23

disruption of the neuromuscular innervation of the muscles controlling vocal fold movement.

Answer 23

vocal fold paralysis

Question 24

could be caused by various conditions: “… concomitant disease processes, vagal recurrent laryngeal nerve (RLN) and /or superior laryngeal nerve (SLN) lesions, trauma, neuritis, and idiopathic issues.”

Answer 24

unilateral or bilateral

Question 25

due to multiple causes; mechanical/paralytic fixation; bilateral vocal fold immobility (BVFI) can be as as result of a primary neurological disorder, metabolic origin, or due to iatrogenic complications of surgery or intubation. This type of paralysis occurred in the past more frequently post thyroidectomy. Per Andrews more VFIs currently are caused by malignancies and nonsurgical trauma than in the past.

Answer 25

immobile vocal folds

Question 26

what are some causes of vocal fold immobility

Answer 26

- Carcinoma (bronchi, lung, larynx, thyroid, esophagus, carotid, nasopharynx) -Diseases ( e.g.,cardiac, autoimmune); - Inflammatory Conditions ( e.g., rheumatoid arthritis); Trauma ( e.g, neck surgery, blunt, gunshot, intubation, TBI; -Central Nervous system Lesions; Infections (e.g, tuberculosis etc..)

Question 27

- Vagus comes via lateral surface of the medulla; after emerging from the skull; vagus divides into left and right; and into three branches: - Pharyngeal branches of the vagus nerve travel down between the external and internal carotid arteries to innervate the pharyngeal constrictor muscles. - They then subdivide and join branches from the sympathetic trunk; and glossopharyngeal and external laryngeal nerves to make the pharyngeal plexus. - The plexus provides innervation to the pharynx and muscles of the velum. Vagus nerve lesions above this point, can cause adductor paralysis of the larynx and paralysis of the velopharyngeal muscle.

Answer 27

innervation of the vocal folds

Question 28

descend from the inferior ganglion and split into internal and external laryngeal nerve branches

Answer 28

the superior laryngeal nerve branches

Question 29

splits into two additional branches which contain afferent (sensory) fibers;

Answer 29

internal laryngeal nerve

Question 30

supplies the mucous membranes of the epiglottis and vestibule of the larynx

Answer 30

upper branch

Question 31

supplies the mucous membrane of the arytenoid cartilages and the dorsum of the arytenoid cartilages. There is a motor supply to the cricothyroid; lesions at this level cause paralysis of the cricothyroid muscle.

Answer 31

lower branch

Question 32

the left recurrent nerve leaves the vagus trunk near the arch of the aorta subsequently enters the larynx. The right recurrent nerve leaves the vagal trunck and ascends beside the trachea behind the common carotid artery and enters the larynx. All intrinsic muscles of larynx except for cricothyroid; are innervated by the left and right recurrent nerve branches.

Answer 32

recurrent laryngeal nerve branches