1. Lecture 3: Laryngeal Endoscopy

2. Laryngeal Endoscopy Laryngeal Exam: Mirror Exam
Transnasal Flexible Endoscopy
Oral endoscopy (rigid scope)
Videostroboscopy (flexible or rigid scope)
High speed videoendoscopy (flexible or rigid scope)
Videokymography
2. Laryngeal endoscopy is used to view the anatomical structure and gross function of the larynx and, if stroboscopy or high speed video is used, the vibratory characteristics of VF vibration can also be assessed. There are a number of techniques used to visualize the larynx and VF function and these are laryngeal mirror exam, transnasal flexible exam, oral endoscopy with a rigid scope, videostroboscopy w/ a flexible or rigid scope, high speed videoendoscopy and videokymography.

3. Laryngeal Endoscopy Laryngeal Mirror Developed by Manual Garcia (1855)
Traditional laryngeal imaging
Utilizes a laryngeal mirror and light source
Useful only for a GROSS assessment of laryngeal structures/anatomy
CANNOT be used to evaluate VF vibratory characteristics or for accurate diagnoses
3. The laryngeal mirror exam was developed by the well known opera singer and singing teacher Manual Garcia in the 1850’s. It soon became the standard of care for examining the VFs. Some ENTs still use the laryngeal mirror exam to obtain a gross view of laryngeal structure, anatomy and gross function. However, assessment of VF vibratory characteristics is not possible with a laryngeal mirror exam and diagnosis should be confirmed by endoscopic exam, preferably videostroboscopy.

4. Laryngeal Mirror
4. Photo of a laryngeal mirror

5. Transnasal Flexible Endoscopy
Nasendoscopy –
*Utilizes a flexible nasendoscope
*Flexible fiber optic cable carries the light source to the scope tip and carries the image to the camera and computer monitor
*Can be used with videostroboscopy
*Newer scopes have a ‘chip in the tip’ digital camera which provides greater magnification and better light.
5. Transnasal flexible endoscopy is often used in the laryngologist’s office. It can be used with or without a videostroboscopy unit. If used without stroboscopy, only gross laryngeal anatomy and function can be assessed. VF vibratory characteristics cannot be assessed without stroboscopy. Prior to passage of the flexible endoscope through the nasal cavity, a topical anesthetic may be applied as well as a lubricating gel to help ease the passage of the scope through the nasal passages and decrease any ‘mechanical’ discomfort experienced as the scope is passed. Patients are awake and typically do not experience pain. The flexible fiber optic cable transmits the halogen or xenon light source to the tip of the scope for illumination of the larynx and the lens carries the image to the camera. Some newer scopes have a digital chip camera at the tip of the scope which provides greater magnification and better light.

6. Transnasal Flexible Endoscopy
Pros – Patient can speak normally and sing Excellent view of supraglottic structures and velar function Less likely to elicit strong gag reflex Cons – Image and color distortion, poor magnification Light less bright *** Digital ‘chip in tip’ scope has better light, image and magnification
6. One of the benefits of using a nasendoscope is that it allows for laryngeal function assessment during complex tasks such as speaking and singing. We can also assess for possible laryngeal muscle tension by observing position and posture of the supraglottic structures. Drawbacks to the nasendoscope include less illumination and magnification than for the rigid scope as well as possible image and color distortion. Nasendoscopes with the camera in the scope tip have greatly improved magnification, illumination and color, but they are quite expensive.

7. Transnasal Flexible Scope
7. Illustration of transnasal flexible scope

8. Rigid Oral Scope
The rigid oral scope is passed through the mouth into the oropharynx
Pros -
Good light and color, excellent magnification
Cons –
Can only produce sustained vowels
Increased likelihood of gag reflex in some patients
8. The rigid endoscope consists of a long metal tube slightly thicker than a pencil. At the tip of the scope is a lens. The light source is carried through the attached fiber optics cables and is emitted from the tip of the scope. The lens at the tip of the scope and the camera (at far end of scope) picks up the image of the larynx and the image can then be viewed on the video monitor. The rigid scope has excellent magnification, illumination and color. However, the patient is only able to produce sustained vowels and the likelihood of a gag reflex is much greater with a rigid scope than with the nasendoscope. If gagging is a problem, the ENT will typically spray the oropharyngeal area, and sometimes base of tongue, with a topical anesthetic to eliminate or decrease the gag reflex.

9. Rigid Oral Scope
9. Image of a rigid scope attached to an older style high speed camera.
Rigid scope being used with an older style high speed camera

10. Videostroboscopy (Karnell)
Primary purposes:
1) Identify physiologic correlates of perceived resonance and voice quality
2) Document status of speech anatomy and physiology during speech production
3) Assist educational and clinical discussion amongst clinicians, patients and others
Secondary purposes:
1) Confirm diagnosis
2) Improve patient motivation and counseling
3) Provide biofeedback therapy
10. Videostroboscopy has become the ‘gold standard’ for laryngeal examination and diagnosis of voice disorders. The primary purposes of a videostroboscopic exam for the ENT are to obtain or confirm the medical diagnosis and to assess the extent and effects of the voice disorder on VF vibration. According to Karnell , the primary purposes of a videostroboscopic exam are to i.d. the physiological correlates of the perceived resonance and voice quality, document the status of laryngeal anatomy and physiology during speech production and assist educational and clinical discussion. Secondary purposes are to confirm the diagnosis and improve patient motivation and counseling. In our clinic, we always show patients their exam and explain the vocal pathology and it’s effect on normal phonation. It helps patients understand their disorder and helps with compliance. Videostroboscopy can also be used for biofeedback during therapy; however, the patient must have a good tolerance for the scope and a low gag reflex for this to be successful.

11. Videostroboscopy Also, videostroboscopy provides
1) info regarding the nature of VF vibration
2) info regarding presence of VF pathology
3) a permanent record for patient hx
4) qualitative and quantitative data on vocal function of the normal and disordered larynx
(Bless et al., 1987)
11. Videostroboscopy provides us with information regarding normal VF vibratory characteristics, VF pathology and the resultant effects of the voice pathology on VF vibration. This information helps us to develop and tailor our therapy plan specifically for a given patient. Videostroboscopy also provides a permanent record for pre- and post-therapy comparisons. I frequently recommend that professional voice users, such as singers and actors, obtain a videostroboscopic exam when they’re vocally healthy as a record for comparison if or when they ever develop vocal problems.

12. Videostroboscopy Components
Rigid oral endoscope or transnasal flexible scope
Camera
Monitor
Light source:
Halogen & Xenon
Laryngeal microphone
12. In order to perform a videostroboscopic exam, one must have a videostroboscopy unit. This consists of a computer with the appropriate software, a computer monitor for video playback, a light box with both halogen and xenon light sources, a camera that attaches to the end of the scope (unless you have a chip in the tip scope), and a laryngeal microphone or electroglottography.

13. Videostroboscopy – How does it work ?
Normal Phase :
Each flash of light illuminates a different part of each successive vibratory cycle. Software combines portions of each cycle into one picture.
The patient’s fundamental frequency (Hz) is used to determine where in the cycle to flash light. (dependent on periodicity of glottal cycle)
Videostroboscopy – How does it work ?
Normal Phase
13. Videostroboscopy uses a light source that is ‘pulsed’ for endoscopic visualization of VF vibration in apparent slow motion. The source of the pulsing light is the xenon bulb in the light box. The laryngeal microphone, or electroglottography unit, tracks the fundamental frequency (Fo) of the patient and the light flashes at 1 – 2 Hz above the Fo and this results in ‘apparent’ but not real time VF vibration. This is called the ‘normal phase.’ The illustration in the slide shows you 4 cycles of VF vibration. The vertical arrow shows where in each cycle the light will flash and the picture will be taken. The individual pictures are then combined together via a computer software program to comprise one cycle of VF vibration. Remember that this one cycle is actually composed of specific sections of many cycles. Thus we are not seeing true real time slow motion VF vibration. We are seeing ‘apparent’ VF vibration. Still, this is a very useful method of laryngeal examination. One drawback of stroboscopy is that if a patient’s VF vibration is moderately – severely aperiodic the software will have trouble tracking the fundamental frequency due to the aperiodic VF vibration and the stroboscopy image will not be as clear. The stroboscopy image depends upon accurate tracking of the patient’s fundamental frequency so that the light can flash and the picture can be captured at the appropriate times, 1-2 Hz faster than the Fo. If the Fo is varying then it will be difficult for the software to track the Fo and determine when to capture the image.

14. Locked Phase is used to assess periodicity.
The light flashes and the camera takes a picture at the same point in every vibratory cycle.
If the vibration is periodic, the VFs will appear to stand still. If the vibration is not periodic, the VFs will move.
Locked Phase
14. Locked phase is used during stroboscopy to assess the periodicity of VF vibration. During locked phase, the light flashes and the camera takes a picture at the same point of every cycle. The illustration above shows 4 cycles of vibration. Notice that the vertical arrows are at the same point for each cycle. If the VF vibration is periodic than the VFs should appear to stand still when the image is produced. If not, the VFs will move about. For example, if the picture is taken at the same point of each closed phase of vibration, then the VFs should appear closed and still if vibration is periodic.

15. Videostroboscopic Exam Protocol with Oral endoscope
Tasks:
1) Sustained /i/ at comfortable pitch & loudness – assess during both normal & locked modes.
2) Short repeated /i/ then sniff
3) Deep sniffs
4) Pitch glides up and down on /i/
5) High pitched phonation on /i/ loud & soft
6) Loud and soft /i/ at comfortable pitch
15. When performing a videostroboscopic exam with an rigid oral scope, the patient will only be able to produce sustained vowels. The tasks we use for assessment are outlined in this slide. Typically, we begin with the bright halogen light in order to assess laryngeal anatomy and gross movements of laryngeal structures. We then switch to the xenon or strobe light to assess VF vibratory characteristics. Deep sniffs show VF abduction, while short /i/ then sniff shows altenating VF adduction and abduction.

16. Videostroboscopic Exam Protocol with Transnasal Flexible Endoscope
Tasks:
Same as for oral endoscope PLUS:
* Speech
* Singing (if pt. is a singer)
* Therapy tasks to assess efficacy of tx
techniques
16. When using a transnasal flexible endoscope for videostroboscopic examination, we use the same task protocol as for the rigid oral scope plus we ask the patient to talk , count etc. If the patient is a singer, we will always have them sing. With a flexible scope, we can even administer therapy probes to see if specific therapy techniques will be beneficial.

17. Videostroboscopic Evaluation
What parameters/characteristics do we evaluate? Assess first at NORMAL pitch/loudness!
1) fundamental frequency 8) Mucosal Wave
2) type of glottic closure ) Phase closure
3) Supraglottic activity ) Phase symmetry
4) Vertical level of VFs ) VF mobility
5) Vocal fold edge
6) Periodicity
7) Amplitude of vibration
17. There are many anatomical and vibratory characteristics and features we assess during a videostroboscopic exam. This slide lists the VF features and vibratory characteristics we evaluate. We will discuss each one in the following slides.

18. Types of Glottic Closure
18. Assessing type of glottic closure is very important. Glottal closure is assessed during the closed phase of vibration at comfortable pitch and loudness. This illustration shows a number of different types of glottal closure. In the center complete glottal closure is shown and to the left of center is a posterior gap. These two types of glottal closure are normal. In fact, approximately 25% of women will present with a posterior glottal gap. To the right of center is bowing. This is not normal but may be observed in Parkinson’s patients and presbylaryngis (aging voice). The top left shows a longitudinal gap which may be the result of VF paresis or paralysis. The top right shows an anterior gap. Most laryngologists feel that this is likely indicative of laryngeal muscle tension. The bottom left shows irregular closure and the bottom right shows an hourglass closure. Hourglass closure is very typical for VF nodules. An abnormal glottal closure pattern can result from poor VF adduction due to RLN damage or cricoarytenoid akylosis (fixation of CA joint), obstruction due to a VF medial edge lesion, laryngeal web, laryngeal muscle tension, granuloma or reduced tissue pliability due to scarring or sulcus vocalis.
Hourglass

19. Evaluation Cont’d Supraglottic activity: Look for presence of
1. Anterior-Posterior compression
2. Medial-lateral compression and/or FVF adduction,
3. Supraglottic squeezing
Vertical level of folds –same or is one VF lower than the other?
Vocal fold edge – Smooth or irregular ?
Rate severity from slight to severe.
Where is the irregularity? Anterior 1/3 of VF ? Mid 1/3? , posterior 1/3 ? etc.
19. We also evaluate supraglottic activity and look for signs of laryngeal muscle tension in the form of anterior – posterior compression, medial-lateral squeezing, false vocal fold adduction or supraglottic sphinctering. We also assess the vertical level of the VFs. Both VFs should be on the same vertical plane. If one VF is lower than the other it may indicate a SLN paresis/paralysis. We also assess the medial VF edge for smoothness or irregularity and rate the severity and location of the irregularity. Irregular VF edges occur due to medial VF edge lesions, VF scarring and edema.

20. Videostroboscopic Characteristics Cont’d
Periodicity*– degree of regularity of VF vibration (use locked phase)
Amplitude of vibration – extent of horizontal excursion of each VF during vibration at comfortable/normal pitch - should be symmetrical.
Mucosal Wave – Rate extent of horizontal excursion of wave. Normal if moves 1/2-2/3 the width of the VFs. Should be symmetrical.
Phase symmetry –Do VFs come to midline (close) together and open together?
Phase closure – What phase, open or closed, predominates the vibratory cycle?, Should be about 50/50 or 40/60
20. It is particularly important to rate the normalcy and extent of the mucosal wave and amplitude of vibration. This is always rated during phonation at comfortable pitch and loudness. The reason for this is that high pitch phonation results in thinner, stiffer VFs and the mucosal wave and amplitude of vibration are normally less for high pitches than for comfortable pitches. The mucosal wave, or traveling wave, excursion is typically 35%-60% of the total VF width. A decrease in mucosal of wave excursion or absence of mucosal wave is seen in cases of decreased tissue pliability, such as scarring, mass lesions, sulcus vocalis, and mucosal dryness. The wave may also be increased, as in cases of polypoid degeneration. The decrease in the wave may be confined to a segment of the VF or occur across the entire VF.
Phase symmetry is a measurement of the degree to which the VFs mirror each other during vibration. During vibration, the VFs should close and come to the midline together. If one lags behind the other, they are out of phase and we call that ‘phase asymmetry’. Phase asymmetry may result from differences in VF mass, length or tension which result from unilateral VF lesions, unilateral neuropathy or unilateral differences in tissue pliability. When we observe phase asymmetry in the absence of the these circumstances, the clinical relevance of the phase asymmetry is uncertain. However, many laryngologists, ENTs who specialize in voice only, believe persistent phase asymmetry may be related to laryngeal muscle tension. Phase asymmetry at the onset and offset of phonation is not unusual.
Phase closure reflects the durations of the relative open and closed phases during an observed vibratory cycle. At comfortable pitch and loudness the open phase may account for 40%-60% of the vibratory cycle. If phonation is loud, the open phase will be shorter and the closed phase will be longer, 70%-80% of the cycle. A vibratory cycle that is predominantly open phase is typically associated with a breathy quality due to incomplete glottal closure.
Voice disorders that result in VF weakness, such as paresis or paralysis, result in longer, predominant open phases. Conversely, a vibratory cycle that is predominantly closed is often associated with a pressed vocal quality due to laryngeal muscle tension dysphonias that result in hyperadduction and foreshortening of the VFs (excess TA activity). Variations in Ps, intensity, vocal register, pitch and vocal effort will also affect phase closure.

21. Videostroboscopic Characteristics Cont’d
Vocal fold mobility – Both VFs should abduct and adduct w/o signs of weakness or paralysis or any sort of impaired movement.
Stiffness – Manifests as lack of mucosal wave and /or decreased amplitude of vibration.
Fundamental frequency – Automatically computed by the computer software. The ‘laryngeal mic’ is placed against the patient’s thyroid lamina and picks up VF vibration .
21. We also assess VF mobility. Both the VFs should abduct and adduct together, i.e. mirror each other as they abduct and adduct. If one side is lagging behind the other during abduction or adduction or both, it may indicate laryngeal muscle weakness. This is easily assessed by asking the patient to take several deep sniffs during which the VFs should maximally abduct. The ‘sniff – eee’ task repeated several times will show alternating abduction and adduction. VF stiffness manifests as a lack of a mucosal wave and decreased amplitude of vibration. A regional absence of a mucosal wave along with absence of vibratory amplitude is called a ‘non-vibratory segment.’ We always note VF stiffness and the location of the non-vibratory segment in our report.

22. High Speed Videoendoscopy
Shows real time slow motion VF vibration
Frame rates are 2000 – frames per second
Can observe the fine details of VF vibration
Can be performed with a rigid or flexible scope
Provides detailed information on glottic closure, vertical phase differences, phonatory modes (registers), mucosal wave behavior, and VF stiffness etc.
22. High speed videoendoscopy (HSV)was first developed by Bell Laboratories in High speed endoscopy gives us a great deal more information than videostroboscopy. Because the ‘apparent’ VF vibration observed during videostroboscopy is composed of sections of successive vibratory cycles, data is lost during the procedure. High speed endoscopy gives us detailed information for every individual vibratory cycle in slow motion. So, why don’t we use HSV clinically? Early on, HSV required a large camera, a very bright light source that generated a lot of heat, and data analysis was time consuming. In addition, the procedure had to be short due to the heat generated by the bright light source or the patient could be burned. For many years, HSV has been used primarily for research which has provided us with a better understanding of the finer details of VF vibration that could not be obtained via videostroboscopy. Over the years, advances in technology have made HSV less cumbersome and the light source somewhat less hot. HSV units are now available for clinical use and are used by some laryngologists in place of videostroboscopy. The clinical application and use of HSV in our field will most certainly increase in the coming years.

23. Laryngeal Endoscopy
Be sure to watch the normal videostroboscopic exams posted on Moodle
Download and look at the stroboscopy rating/report forms on Moodle
See if you can rate the normal exams using the ratings forms!
I will post the ratings key on Moodle
Be sure to watch the endoscopy information videos as well.