1.64 Phonation

Question 1

How is speech produced?

Answer 1

1. Air driven of lungs under pressure
2. When driven through closed glottis phonation is created
3. Vocal note modified and amplified in resonance chambers - pharyngeal, nasal and oral cavity
4. contristion and closures by the tongue and teeth

Question 2

What is the function of the velum?

Answer 2

lowering-raising produces nasal vs oral resonance.
Contrast nasal-oral sounds (m-b, n-d, ng-g; my-buy, no-doe, log-long), main difference between these pairs is whether air directed via nasopharynx or mouth

Question 3

What can vary speech loudness?

Answer 3

Speech varies in loudness and pitch: these in turn dependent on fine balance between subglottal air pressure/flow and length and tension of vocal cords

Question 4

What determines intensity?

Answer 4

Intensity (loudness) determined by subglottal driving pressure x tightness of approximation of vocal cords:

Question 5

What determines the frequency?

Answer 5

Frequency (pitch) determined by tension in vocal cords (intrinsic tension); stretching by cricothyroid muscle; and rate of airflow

Question 6

What are target regions?

Answer 6

Target regions with critical boundary lines where minimal alteration of articulatory setting brings maximum change in sound
Auditory targets/auditory ‘memories’ guided online by feedforward models (frontal-cerebellar circuits)

Question 7

Which ares control speech output?

Answer 7

superior, posterior temporal lobes
parietal (links meanings-sounds)
left anterior insula, frontal operculum, L posterior-inferior frontal gyrus (speech motor control)
Subcortical circuit inputs to motor control and feedforward model - thalamo-cortical; basal ganglia; cerebellar

Question 8

Explain Dysarthria…

Answer 8

alterations of tone, power, coordination
• which give:
• reduced breath support; lack of coordination with phonation
• altered laryngeal resistance: too much/ too little: impression of breathy vs creaky voice
• effect on stress, intonation, rate, length of utterance
• changed velum stiffness: excessive nasality
altered tongue, lip movements: lose contrasts between groups of sounds, places and manner of articulation e.g. ‘key’ sounds like ‘tea’; ‘tea’ like ‘see’ or ‘see’ like ‘he’

Question 9

define apraxia or phenemic paraphasia…

Answer 9

Either problems ‘planning’ speech movements

Question 10

define dysarthria and dysarthrophonia…

Answer 10

disruption to voice and speech from alteration to neuromuscular function