Examination of Patients with Voice Disorders
Introduction: Voice problems are common in patients these days. The major reason being the stressful environment and changing life styles which are getting common these days. The commonest cause of voice disorder is voice abuse.
History taking: Before pluinging directly into the history taking, it is always better to listen to the patient's complaints in his or her own words. This will give a vital insight into the expectation of the patient. Over expecting patient may be so disappointed with the results of therapy, they may even fall into a spell of depression. The emotional component of the voice disorder must always be kept in mind.
The patient must be carefully questioned pertaining to the following issues:
1. The precise date of onset of the problem, whether it was abrupt or gradual.
2. History pertaining to upper respiratory infections / sinusitis. Without addressing the issue of focal sepsis the treatment may not be successful.
3. The patient must be carefully quizzed whether his voice was absolutely normal before the trouble began
4. History pertaining to gastro oesophageal reflux disease must be ascertained. i.e. presence of burning pain the chest is one classic example.
5. The patient's job, and the stress it puts on his or her voice should be ascertained
While speaking to the patient the voice of the patient is carefully listened to and a recording is made for subsequent comparison. A description of the voice should also be included. The following descriptions could be useful at a later date:
1. Whether the voice is low or high
2. Whether it is loud or soft
3. Whether it is powerful or weak
4. Whether it is clear, breathy or hoarse
5. Whether sharp or dull
6. Whether resonant or falsetto
7. Whether relaxed or strained
The voice could be grossly described as either hyperkinetic or hypokinetic.
Hyperkinetic voice: is a tense voice associated with a forceful closure of glottis and a high subglottic pressure.
Hypokinetic voice: is a voice with very little energy and associated with wastage of air from subglottis.
Posture: The posture adopted by the patient should be carefully noted. It could be tense, relaxed or slouched.
Breathing habit: of the patient is also observed by noting the movements of the abdominal wall, whether the accessory muscles of respiration are active.
Examination of the nasal cavity is a must. Nasal discharge if any must be documented. Post nasal drip any must also be noted. Sine vocal cords are highly mobile structures, they are likely to be infected when exposed to secretions from the nasal cavity from above or from lungs below.
Indirect laryngoscopy: is done using a laryngeal mirror. The vocal cords and the ventricular bands are carefully noted for any structural anomalies. Their mobility is also assessed.
Radiological examination: Should include
1. CT scan of para nasal sinuses - to rule out sinus infections
2. Plain x-ray chest - to rule out bronchial infections
Functional assessment of voice: can be done by eliciting various kinds of voice production. During the examination the way in which the patient's voice changes in response to the following instructions are observed:
Factors causing voice disorders can be classified under these three heads:
Subjective analysis of voice can be done using Voice Handicap Index (VHI). This method was devised by Jacobson in 1997. This is done by the patient. They must assess their voice under three heads (domains) i.e. Emotional (E), Physical (P), and Functional (F). They must assess their voice under the above three heads on a five point scale and grade as follows:
The scale starts from 1 (which is never)
Ends at 5 (Almost always).
The scores are tabulated under each domain and totalled.
Special methods of examination:
I . Tape recording of the voice: This has several advantages:
a. It provides a base line for future comparisons
b. It will allow the examiner to focus on features of voice and articulation
c. These features can be discussed with the patient and he can be made aware of the problem and its magnitude.
II . Phonetogram: is also otherwise known as pitch intensity profile. The examiner's subjective assessment of the loudness, pitch and quality of voice can be supplemented by this objective measurement. The instrument used is costly but user friendly. The phonetogram examiantion starts with a measurement of singing voice profile of the patient. The patient can sing in a sustained tone freely and measurement can be made. Alternatively, the examinee can be requested to match tones produced by the examiner on a keyboard. The measured values for pitch and intensity appear are plotted as a graph for further study.
Image showing a phonetogram recording
The phonetogram covers the entire frequency range, while a speaking voice uses only part of the range. Hence speaking voice profile must be separately measured by asking the patinet to count numbers in normal voice and then in a tense voice mode. A sound level meter is used to assess the level of sound generated by the patient for each mode.
Different computer softwares are used for phonetogram recording: Some of the common ones are
1. Dr. Speech
2. Aeroplane II
III. Stroboscopy: This is an excellent tool for examining the movements of the vocal cords in their various phases.
Oertel used a stroboscopic light source with a laryngeal mirror to investigate voice production in different registers. The application of the stroboscopic light source allowed the observer to view the vibrating vocal folds in arrested or apparent slow motion, permitting detailed observations of the structure in the open or closed positions. Because of the limitations in illumination, precise control of the flashing frequency, poor image quality, and patient discomfort, members of the scientific community did not embrace this technique.
Stroboscopic images are generated using a flashing light source create the illusion of motion . This is due to the phenomenon of persistence of vision. This practice is believed to date back to the ancient Greeks. The movement of vocal folds can be captured by using flashing lights. The frequency of the flashing lights should be in close relation to the vibration of the vocal folds.
Strobolaryngoscopy takes advantage of these principles by producing intermittent light flashes in close relation to the frequency of the vocal-fold vibration. A microphone picks up the frequency of the examinee's sustained voice, which triggers the stroboscopic light source. With the provision that the vocal vibrations are periodic, a frequency of light flashes equal to the vocal frequency produces a clear, still image of the same portion to the vibratory cycle.
A videostrobe unit consists of a stroboscopic unit (light source and microphone), a video camera, an endoscope, and a video recorder. Stroboscopy can be performed by using either rigid or flexible endoscopes. Flexible endoscopes are better tolerated by the patient, but the image resolution leaves much to be desired. Rigid endoscopes use telescopic lenses, they are poorly tolerated by the patient, but the images produced by it are of excellent quality.
The following parameters can be assesed using stroboscope:
a. The fundamental speech frequency of the patient
b. Periodicity: It refers to the regularity of the successive vocal fold movements
c. Symmetry: Normal vocal folds vibrate in a symmetric manner
d. Glottic closure: During normal vibratory phase the membranous portion of the vocal cord firmly apposes, while the posterior glottic chink may be open.
e. Mucosal wave: The pattern of light traveling from mediolaterally along the superior surface of the vocal fold during vibration under illumination is referred to as the mucosal wave. It is a correlate of the pliable cover (epithelium and superficial lamina propria) of the vocal fold being displaced relative to the body of the vocal fold (vocalis muscle). Focal abnormalities of mucosal wave help to localize pathology in the vocal fold.
Thus video stroboscopy helps in diagnosing even mild defects in the vocal cord mucosal covering.