Chapter 6: Instrumental Measure of Voice Flashcards
Treatment outcomes measures need to be _____________, _______, ______________, and ____________ to heterogeneous voice qualities and severities.
objective
valid
automated
sensitive
What are 5 types of instrumental measures of voice?
1) acoustic recording and analyses
2) aerodynamic measurement
3) laryngeal imaging
4) electroglottography (EGG) (measures VF contact area)
5) laryngeal electromyography (LEMG) (direct measures of muscle activity)
What are the 3 basic types of technical instruments?
1) signal detection
2) signal manipulation or conditioning
3) signal reconversion
What 4 technical instruments are used for signal detection?
1) microphone
2) camera
3) electrode
4) flow/pressure transducers
What 3 technical instruments are used for signal manipulation or conditioning?
1) filtering
2) amplification
3) digitization
What 3 technical instruments are used for signal reconversion?
1) numerical form
2) visual display
3) speaker
Acoustic measurements can provide ____________ and ________________ analysis of vocal function
objective
noninvasive
Clinical utility of acoustic measures depends upon whether the acoustic measures: (3)
1) can discriminate between normal and disordered voices
2) correlate with auditory-perceptual judgements of voice quality and severity
3) sufficiently stable to assess real change in performance across time
Most acoustic measures are mathematical derivations of 5 common measures:
1) fundamental frequency
2) intensity
3) perturbation measures
4) ratio of signal (i.e. harmonic) energy to noise
5) spectral or cepstral features
What is fundamental frequency?
rate of vibration of the vocal folds expressing in Hz or CPS
What is the perceptual correlate of F0?
pitch
What are 2 clinical measures related to fundamental frequency?
1) mean F0 (for connected speech vs. sustained vowels)
2) F0 range (highest and lowest pitch a patient can produce)
What is the acoustic correlate of vocal loudness?
vocal intensity
Intensity is referenced to _________ ___________ __________ (___) and measured on a _______________ _________ (__) scale
sound pressure level (SPL) logarithmic decibel (dB)
What two measures of intensity are clinically useful?
1) habitual intensity
2) intensity range (min and max)
What are 3 potential instruments for measuring intensity?
1) sound level meters
2) acoustic analysis programs
3) aerodynamic measurement devices
What does frequency-intensity profiling give a thorough description of?
patient’s physiologic limits of frequency and intensity
How do you do frequency-intensity profiling? (3)
1) voice range profile
2) phonautogram
3) physiologic frequency range of phonation
What are the two major types of voice acoustic analysis?
1) time-based measures
2) frequency-based measures
What are time based measures of voice?
perturbation measures such as jitter and shimmer
What are frequency based measures of voice?
spectral and cepstral
What is perturbation?
cycle-to-cycle variability in a signal
What voice production is typically used to measure perturbation?
sustained vowel production
What is jitter?
cycle-to-cycle variability in frequency
What is shimmer?
cycle-to-cycle variability in amplitude
Calculation of perturbation measures requires a ________________ (aka Type I) signal for realizable/valid analysis
quasi-periodic
What is a signal(harmonic)-to-noise ratio?
ratio of periodic/harmonic signal energy to aperiodic/noise energy in the voice waveform
What is the SNR for normal voices?
mostly periodic and high signal/harmonic energy, high SNR/HNR
What is the SNR for dysphonic voices like?
increased aperiodic/noisy components (roughness, breathiness, turbulent), thus “low” SNR or HNR
What are the 2 limitations of time-based perturbation measures?
1) depends on accurate identification of cycle boundaries, so results become questionable in moderate to highly perturbed voice signals
2) time-based measures are based on assumption of relatively steady pitch and loudness (sustained vowels)
In contrast to tradition time-based analysis, spectral-based acoustic measures have the ability to characterize the voice signal by extracting characteristics such as the __________________ _______________ and the relative ___________ of ______________ versus ____________ without needing to identify cycle boundaries.
fundamental frequency
amplitude of harmonics vs. noise
The spectral-cepstral analysis methods analyzes ___________ of data rather than __________
frames
cycles
What does spectral analysis assess?
the interaction between glottal sound source (VFs) and the supraglottic (vocal tract) influences
What are types of spectral analysis?
1) spectrogram
2) line spectrum
What does a spectrogram plot?
plots F0 and L0 in the time domain
What does a line spectrum plot?
plots all harmonic energies at a single point on the horizontal axis, with amplitude on the vertical axis
Subglottic pressure and transglottal flow indirectly asses what?
laryngeal valving mechanism (and vocal function)
What are 3 additional measures that integrate pressure and flow in a ratio?
1) glottal power
2) laryngeal resistance
3) vocal efficiency
What is phonation threshold pressure (PTP)?
the minimum subglottal pressure needed to initiate vocal fold vibration
Instruments that measure speech aerodynamics exploit the integral and predictable relationship between what 3 things?
1) pressure
2) flow
3) resistance
What is pneumotachograph?
uses differential pressure across a known resistance to estimate flow rate
What are 2 common airflow measures?
1) mean flow rate
2) phonatory volume
What is mean flow rate?
flow divided by time (ml/sec)
What is phonatory volume?
1) total amount of flow during a given speech/voice task (liters or mls)
What is pressure?
force per unit area
What is subglottal pressure (ps)?
force beneath the adducted vocal folds
How is ps estimated/measured?
indirectly using intraoral pressure during repeated productions of unvoiced /p/ and vowel syllable (e.g., /pi/)
How is subglottal air pressure instrumentally measured?
oral tube between the closed lips and connected to pressure transduced records intraoral pressure
PTP is the minimal driving ______________ to set the _________ _________ into _____________.
pressure
vocal fold
oscillation
PTP is a possible predictor of __________ and ___________ of the VF vibratory capabilities?
structure
function
Theoretically, the healthier the VFs, the _______ the PTP need to power vibration
lower
There is some evidence that PTP is correlated with “the ________” associated with voicing/phonatory effort
effort
What is laryngeal resistance (LR)?
the quotient of peak intraoral pressure divided by the peak flow rate
LR is intended to reflect overall _______________ of the _________ and estimates ____________ _________ function (cm H20/l/sec)
resistance
glottis
laryngeal valving
What are the 3 possible laryngeal valving functions?
1) hyperfunction
2) hypofunction
3) normal (as compared to normative values)
What is laryngeal valving hyperfunction?
valve too tight, LR too high
What is laryngeal valving hypofunction?
valve too loose, LR too low
What type of imaging can provide more information about the severity and nature of a voice disorder than others?
laryngeal imaging
What is the visible evidence that appears in laryngeal imaging?
1) structure
2) movement
3) function
What are the 2 types of endoscopes used?
1) flexible
2) rigid
What are 3 types of laryngeal imaging techniques?
1) stroboscopy (most common clinically)
2) kymography
3) high speed digital imaging (HSDI)
What are the 2 types of rigid scopes?
1) 90 degree
2) 70 degree
What is stoboscopy?
special lighting technique wherein a stroboscopic light flashes at specific moments to form a composite vibratory cycle
How does the strobe light flash in stroboscopy compared to the F0?
flashes at phase points in VF vibration that is slightly faster than the F0, which means it gets images of different points of VF vibration
What can compromise clinical utility of stroboscopy?
significant apreiodicity
What is high-speed digital imaging?
“direct” recording of true vocal fold vibration
What is the light source of HSDI and how is it put into the oral cavity
1) very bright Xenon light source
2) rigid endoscope
How does HSDI work?
samples VF vibration at 2,000-10,000 samples per second
HSDI is fast enough to allow real-time recording of “actual” VF oscillation including what 4 things?
1) phonatory onset
2) phonatory offset
3) sustained voice
4) changes in pitch and loudness`
HSDI is fast enough to allow real-time recording of “actual” VF oscillation including what 4 things?
1) phonatory onset
2) phonatory offset
3) sustained voice
4) changes in pitch and loudness`
Unlike stroboscopy, HSDI doesn’t rely on ________ to create an image.
F0
What is kymography?
real-time imaging that uses a camera to scan a horizontal line of VF vibration at a rate of 8000 lines per second
The kymographic image is limited to the _________ and ____________ changes of a single horizontal line of bilateral fold VF movement
spatial and temporal
What does kymography reveal?
1) cycle-to-cycle variability
2) left- or right-sided asymmetry
3) mucosal wave and amplitude
4) open or closed phase timing
5) phonatory onset and offset movements
6) upper and lower focal fold margin changes
What are 4 gross observations that can be made from stroboscopy/imaging (visual perceptual judgements)?
1) glottic closure (static)
2) supraglottic hyperfunction
3) mucus
4) general appearance and movement
What are 6 vibratory features that can be observed from stroboscopy/imaging (visual perceptual judgements)
1) glottic closure (vibratory)
2) phase closure
3) symmetry
4) mucosal wave
5) stiffness/nonvibrating portion/adynamic segment
6) periodicity
What is electroglottography (EGG)?
non-invasive tool that uses electrical current passing through the neck to measure VF contact across time
In EGG, there are 2 _______________ placed on either side of the ________ _____, with a small current passing through as VFs vibrate?
electrodes
thryoid alae
In EGG, electrodes measure the __________ ______________ as VFs vibrate
variable resistance
The EGG waveform displays/plots the variable resistance across time and serves as a ______-time __________ of the VF ______________ __________
real-time
analog
vibratory pattern
What is laryngeal electromyography (LEMG)?
a direct measure of laryngeal muscle activity and function
an invasive procedure performed by otolaryngologists or neurologists
How is a LEMG done?
needle electrodes inserted percutaneously into laryngeal muscles and pattern of electrical activity is studied, vocal tasks are used to confirm correct placement in target muscles
What is LEMG used for? (3)
1) diagnosis/prognosis of suspected VF movement disorders
2) distinguish unilateral VF paralysis from mechanical fixation of cricoarytenoid joint
3) guide intramuscular injection of Botox for the treatment of spasmodic dysphonia
