laryngeal system Flashcards
period
time it takes to complete one cycle of vibration; indirect relationship with frequency
frequency
measured in cycles per second, Hz; perceptual correlate is pitch
amplitude
magnitude of vibration measured in dB SPL; perceptual correlate is loudness
phase
temporal relation of sine waves within a complex wave
constructive interference
sine waves add together
destructive interference
sine waves are out of synch and cancel each other out; perfectly out of synch –> silence
complex tones
comprised of multiple sine waves of different frequencies; human voice
Fourier Analysis
breaks down a complex waves into its sine waves
waveform
shows a sine wave; x-axis is time, y-axis is amplitude
spectrum
shows a sine wave or complex wave; x-axis is frequency, y-axis is amplitude
spectrogram
shows energy of speech; x-axis is time, y-axis is frequency
human voice spectrum
formants represent peaks; higher fundamental frequency means less spectral density - harmonics are whole number multiples, lower Fo = harmonics closer together, higher Fo = harmonics more spaced out
thyroarytenoid
body of the VF; responsible for subtle pitch changes; isometric function is longitudinally stretching VF to increase pitch, isotonic function is thyroid and arytenoids move in, relaxing TA to decrease pitch
cricoarytenoid
responsible for more dramatic pitch changes via rocking and gliding; pars recta passively stretches TA by rocking; pars oblique passively stretches TA by gliding
lateral cricothyroid
adducts the membranous portion of the VF (anterior 2/3); responsible for medial compression, or how tightly the VF close at midline
interarytenoids
adduct the cartilaginous portion of the VF (posterior 1/3); 2 muscles - transverse and oblique
posterior cricoarytenoid
abducts the cartilaginous portion of the VF; only laryngeal abductor
indirect laryngoscopy
uses dental mirror in the back of the throat; pre-technology visualization technique; can see if VF are straight and white (what ENTs care about)
laryngeal endoscopy with flexible scope
camera/wire through the nose; used for those who cannot tolerate rigid scope; patient can phonate bc camera is not in mouth
direct laryngoscopy
done by ENTs for cancer biopsies
ultra-high-speed photography
first method to see VF actually vibrating; camera pulled film fast then played back slowly
laryngeal video stroboscopy
camera hooked up to Fo censor worn by patient; snapped images at different points throughout VF vibration cycle and played back together; with strobe light looked like a continuous cycle
high-speed video endoscopy
latest technology; independent of Fo, catches VF vibrating and slows it down
breathy onset
VF open with unmodulated airflow when phonation begins
abrupt onset
aka glottal attack; VF are closed when phonation begins, airflow starts after building up subglottal pressure; actually hear the beginning of phonation
simultaneous onset
ideal; VF return to midline and phonation begins with controlled airflow
epithelial layer of lamina propria
thin, shiny mucosal layer; what we actually see vibrating; just follows whatever is going on underneath
superficial layer of lamina propria
like gelatin; most active layer in vibration; also called Reinke’s Space
intermediate layer of lamina propria
elastic fibers that help the VF return to rest position after longitudinal stretching
deep layer of lamina propria
contains collagenous fibers; no active role in vibration, supportive structure
3 perceptual voice qualities
breathy: incomplete closure, aperiodic vibration
harsh: complete closure aperiodic vibration
hoarse: incomplete closure, aperiodic vibration
4 objective measures of voice quality
jitter, shimmer, harmonics to noise, cepstral peak analysis
jitter
short-term perturbation of pitch, long-term version is amplitude
shimmer
perturbation of amplitude; no short-term vs long-term
harmonics to noise
measure of the energy in frequencies between the harmonics compared with the harmonic energy; want high signal to noise ratio, or strong harmonics compared to background noise
cepstral peak analysis
voice quality measure of connected speech; has valid norms, easier to obtain, better reflects voice quality in everyday voice, better corresponds to listener perception
phonatory threshold pressure
amount of pressure that is required to blow the VF apart for the first cycle of vibration; singer will have higher PTP before warming up
intraoral pressure transducer
measures subglottal pressure by measuring intraoral pressure on /p/, calibrated with a manometer
Psg direct measure
pressure censor tube below level of the VF through tracheal puncture
ideal Psg for speech
5-10 cmH2O, but can range up to 40cmH2O
eliciting fundamental frequency range
ideally 2 octaves or 24 semitones
take best of 3 trials, provide instruction and models
instruct client to say “ah” and glide as low as possible 3x
instruct client to say “ah” and glide as high as possible 3x
eliciting maximum phonation time
ideally 15-20 seconds
tell client: whenever you’re ready, take a deep breath and say “ah” in a normal, comfortable voice and hold it as long as you can
eliciting loudness range
ideally 20-30 dBSPL
elicit “ah” as quiet as possible
elicit “ah” as loud as possible without screaming
if think client can go louder, cue with a model
newborn laryngeal anatomy
larynx higher in the neck - less space for for food/liquid to get lost, more direct path to esophagus
arytenoids are large & cartilaginous portion of VF are 1/2 the length - when PCA contracts, VF open quick so baby can breathe easy
lamina propria is not differentiated between layers
membranous length of VF is 2mm at birth
laryngeal changes with older childhood
by 4, superficial layer of lamina propria is differentiated from intermediate/deep level
by 6-15, all layers of lamina propria are separated
for first 20 years, VF grow .7mm/yr in males and .4mm/yr in females
by 16, larynx structures are adult-like
voice matures around 20 and is steady until 60yo
boys & laryngeal changes with puberty
begins around 12-13, done around 15-18
lower pitches tend to be more stable than upper pitches
most active changes occur within 1yr
girls & laryngeal changes with puberty
less obvious than boys
increased breathiness with occasional cracking
lower Fo
less accurate pitch production when singing
caused by changes in resonance with facial changes, descent of larynx, increased circumference of chest wall
female Fo decreases with age
caused by lamina propria changes adding mass
superficial layer becomes edematous
intermediate layer’s elastin fibers atrophy
deep layer’s collagen increases in size and density
male Fo increases with age
caused by loss of mass in the thyroarytenoid muscle
male-female coalescence theory
hormone changes associated with menopause reverse some of the hormonal differences that occur at puberty
where do vocal nodules grow
midpoint of anterior 2/3 of VF because of high lateral excursion at that point
what voice quality will very active lateral cricoarytenoid muscles produce
harshness because they are responsible for medial compression
shimmer gives information about…
consistency of vocal fold opening in cycle of vibration
3 vocal registers
3 modes of vibration
modal register, pulse
register, falsetto
modal register
chest register, most commonly heard in speech
pulse register
vocal fry, lowest register, often at the end of utterances - not bad for you if true vocal fry; very low subglottal pressure, if you increase you’ll flip into modal register
falsetto
very high, rarely heard in conversational speech; only thin edge of VF are vibrating; very low subglottal pressure, minimal vibration
