Instrumental/Acoustic assessment Flashcards
What is an indirect laryngoscopy and what are the limitations?
Laryngeal mirror inserted into oropharynx to reflect VF.
Quick and minimal trauma/pain.
Limitations:
Activates gag reflex.
View of larynx may be difficult.
Patient unable to speak normally.
What is involved in a laryngeal examination?
A. Indirect laryngoscopy B. Direct laryngoscopy C. Fiberoptic laryngoscopy (flexible or rigid) D. Stroboscopy E. High-speed imaging
What is a direct laryngoscopy and what are the advantages/limitations?
Requires hospitalisation and anesthesia.
Endoscope inserted into oropharynx.
Advantages: Detailed exam (biopsies) Enable manipulation of structures.
Limitations:
Invasive, costly, unable to observe laryngeal function.
What is a fiberoptic laryngoscopy?
Bundle of fibres (some carry light others carry camera).
Rigid fiberscope:
Rigid tube inserted into oropharynx.
Limits speech etc.
Restricted access to laryngeal cavity.
Flexible fiberscope: Passed through nasal cavity. Local anaesthetic required. Scope positioned above epiglottis. Flexibility and zoom available. Patient can speak and sing. Overcomes hyperactive gag.
What is a stroboscopy?
Stroboscopic light source (rigid or flexible).
Enables detailed view of vibratory behaviour of VF.
Light pulse at rate of vocal frequency = image static.
Light pulse > or < than vocal frequency = slow motion view of VF vibration.
Over successive vibratory cycles images become fused = slow motion image.
What are the parameters you are looking for in a stroboscopy?
Symmetry of movement.
Regularity of successive vibrations.
Glottal closure.
Amplitude (horizontal excursion).
Presence and size of mucosal wave.
Presence of non-vibrating portions of VF.
Presence of lesions and effect on vibration.
What is involved in high-speed imaging?
Can provide imaging of vocal fold up to 2000 times per second.
Allows a more sophisticated (clearer) examination of vocal fold vibration.
Relatively costly.
Mainly for research purposes.
What is involved in a physiological evaluation?
A. Electro-glottography (ECG)
B. Laryngeal aerodynamics
C. Electro-myography (EMG)
D. Respiratory function
What is involved in an electro-glottograph?
2 electrodes placed externally on thyroid cartilage - small electrical current passes between the 2.
When VF abduct no electrical current passes.
When VF adduct the current passes freely between the electrodes.
Changes in the flow of electrical current = glottal cycle
Measures vocal contact area.
Breathy = relatively long open phase
Harsh = Short open phase
F0 = Period of glottal cycle (length of time for VF to make one complete vibratory cycle)
Duty cycle = Also called open quotient, ratio of time that VF are open compared to entire glottal cycle.
Closing time = time from totally open to totally closed.
What are the clinical applications of an EGG and what are the limitations?
Assessment
Biofeedback
Monitoring therapy
Limitations:
Electrode placement
Keed to keep resistance low
What are the parameters tested for in laryngeal aerodynamics?
Air flow rate Subglottal air pressre SPL Laryngeal resistance Ad/abduction rate of VF
Done with an aerophone II
What is involved in an electromyography (EMG)?
Measure electrical activity of muscles.
Direct - electrodes inserted into specific muscles
Indirect - Surface electrodes - less precise
Parameters: Onset/offset muscle activity Pattern muscle activity Amplitude of activity Abnormal: extraneous bursts of muscle activity, muscle activation more or less than normal.
Used to confirm VF paralysis, guiding botox injections.
What is assessed in respiratory function?
Spirometry used to check vital capacity (VC) and forced (expiratory) vital capacity (FVC).
Kinetic assessment used to record changes in circumference of rib cage and abdomen. Determines presence of asynchronous or arrhythmic respiratory behaviours.
What is involved in acoustic analysis?
A. Visipitch
B. Computerized speech lab (CSL)
C. Phonetogram/voice range profile
What is involved in visipitch?
Real time display of F0 and range. Parameters: Average F0 and range Average intensity and range Frequency perturbation (jitter) Amplitude perturbation (shimmer) Noise-to-harmony ratio
