Videostroboscopy

Laryngeal Videostoboscopy

For advanced evaluation of voice disorders.

Kay’s Digital Strobe, an innovative, digital video endoscopy/stroboscopy system, sets a new benchmark for image quality and convenience for endoscopy and stroboscopy examination recordings. Patient exams are recorded directly to the computer storage media. Image quality is breathtaking with equivalence to professional broadcast standards. It is superior to previous generation recording technology based on SVHS videotape recorders. Digitizing the video examination also brings many convenient benefits. For example, any examination can be located and viewed in seconds because there is no need to rewind or fast forward to the start of an examination. And unlike videotape, the recorded images never degrade. Comparing exams is also easy and direct because two exams can be loaded and played side by side.

Kay’s new Digital Strobe joins the Basic Stroboscopy System and Computer-Integrated (VCR) System to provide a complete family of endoscopy/ stroboscopy systems appropriate for any budget and performance requirement.

An Image Capturing System

Kay’s Digital Strobe includes all of the capabilities needed for capturing moving and still images. This includes light source, camera, recording system, microphone, and printer. Audio (patient audio or examiner comments) and video are captured together. To ensure precise color accuracy and fast setup, the computer system downloads the optimized stored camera settings for each endoscope. The image quality is broadcast level with progressive scan display (no flicker). Shades of red are the most difficult for a video system to record. Kay’s system bypasses this shortcoming of analog video recording by storing the images directly in digital format. Once captured, the images can be formatted with text as a report in Microsoft® Word.

Features

• Bright clear images for both endoscopy and stroboscopy
  
• Superior image quality as compared to analog videotape recording
  
• Immediate recall and playback of recorded examinations
  
• Quick and easy comparison of examinations (e.g., pre- and post-surgery)
  
• Numerous features to help in viewing examinations
  
• Excellent pitch tracking for stroboscopy examination
  
• Option for high speed videokymography

Value of Stroboscopy

Stroboscopy provides a slow-motion view of the vocal folds as they vibrate. It is critical to observe the vibratory characteristics of the vocal folds in order to accurately assess phonatory function, and, in some cases, to detect and/or differentiate lesions. Stroboscopy is the only practical tool for observing vocal fold symmetry, amplitude, periodicity, completeness of vibratory closure, and the diagnostically important mucosal wave. The examiner can observe these important physiologic characteristics and gain an understanding of the patient’s voice quality. Most importantly, stroboscopy assists the clinician in determining the most appropriate course of treatment for the patient.

Subtle vibratory characteristics are directly observed using stroboscopy. For example, vibration asymmetry is difficult or impossible to detect with a laryngeal mirror or constant light endoscopy. Symmetry is the degree to which each vocal fold is in synchrony with the other. Symmetrical vibration indicates that the folds have similar mechanical properties.

The vocal folds have two vibratory movements: the transverse movement of the muscular "body" and the more vertical movement of the overlying layer. With stroboscopy, it is possible to observe both the transverse opening and closing of the folds and the vertical sliding motion of the mucosal cover over the body. This latter movement is referred to as the mucosal wave and is indicative of the elasticity of the vocal folds. Stroboscopy is also critical in helping plan and evaluate results of phonosurgery because the surgeon can observe the incremental progress of the healing of the vocal folds.

Numerous articles and books have established stroboscopy as an essential tool in assessing voice patients. Some studies have favorably quantified the extent to which stroboscopy was found to be diagnostically significant or resulted in changed diagnosis (when compared to endoscopy-only assessment). There are many videotape presentations about the value of stroboscopy. Kay offers a videotape (Video Laryngeal Stroboscopy), available at no charge, which explains stroboscopy and provides more than 30 clinical examples from actual examinations. An extensive bibliography and selected reprints are also available.

Superior Light Source

Kay’s dual light source (constant halogen and flashing xenon) provides excellent illumination for both rigid and flexible endoscopy examinations. When not used for stroboscopy exams, the constant light can be applied to normal endoscopy procedures.

The stroboscopy mode provides excellent images of the vibrating vocal folds. The Kay system contains superior pitch extraction and an anti-blinking circuit for consistent brightness. The new xenon light source has a brighter and longer-lasting bulb. It is brighter than earlier generation bulbs, and lasts approximately 1000 examinations before requiring replacement.

Kay’s light source has all of the necessary features for maximum quality and versatility: xenon and halogen light sources; slow, fast, and locked stroboscope modes; foot control of important functions; LED display of amplitude and pitch; audio pre-amplifier; extensive dynamic range of pitch extraction; EEG or throat microphone input; fast lock-on times; and field-replaceable bulbs.

Anti-Blinking Circuit

All stroboscopy systems produce a blinking light. However, other systems vary in brightness during vocalization and with changes in pitch and amplitude. Kay’s light source includes a special circuit that eliminates blinking video and provides consistent brightness throughout the patient’s pitch and amplitude range.

On-Screen Display of Important Information

Pitch and intensity information are both updated in real time. Patient, facility, and, date information can also be added. An electroglottographic (EGG) waveform display is time-synchronized with the image.

A variety of user-selected information can be displayed on the screen to help interpret the examination. Pitch, intensity, and phase information are updated in real time as is the strobe mode being used. Patient, facility, and exam date information can also be displayed.

Control of Camera

A key benefit of Kay’s system is software that includes special code for controlling the camera. Each camera setting, including white balance, gain, shutter speed, ALC, hue, chroma gain, AP gain, pedestal, etc., is stored in the computer for each endoscope and each light source (i.e., xenon or halogen). These settings are downloaded from the computer to the camera, as needed. With this feature, the examiner obtains consistent color and faster examinations because there is no need for ongoing camera adjustments. Color accuracy is especially critical in assessing degree of inflammation.

When performing nasal endoscopy, which usually has wide brightness variations, the foot pedal can be used to control camera shutter speeds. Kay’s system is delivered with settings for many of the available rigid and flexible endoscopes and commonly used otoscopes. Additional settings for other scopes or light sources can be easily generated and stored by examiners.

Professional Quality Video

Medical records require high-quality video images without artifacts. Kay’s Digital Strobe includes a professional-level, video capture/compression board (with audio). It produces very accurate and artifact-free, broadcast-quality video images. This board is currently used for video capture and editing by the major broadcast networks.

Kay’s video capture hardware uses a high sampling method and "component" level recording which result in a very accurate representation of the video signal. It is, in fact, superior to SVHS analog (VCR) recording. Even high-end, consumer-level boards, which use less accurate sampling and achieve VHS to near-VHS quality, never achieve the medical-grade quality of the Kay system.

Inferior hardware may create motion artifacts (e.g., jerky display due to skipped frames) which are detrimental to analysis of laryngeal function. An added advantage of the improved video sampling in Kay’s system is that reduced noise in these signals allows higher video compression ratios (i.e., noisy video is difficult to compress) and, therefore, less memory is needed to store the video signal. Kay’s system yields pristine images without artifacts at practical compression ratios.

The broadcast-quality hardware used in the Digital Strobe results in accurate motion representation and true color. For example, the color red is often smeared in video representations—this problematic color is displayed accurately to facilitate assessment of inflammation during an endoscopy procedure.

One Person Operation

The many features of the Digital Strobe are designed to allow an examiner to perform fast and accurate examinations and quick review of recorded examinations. During an examination it is a critical benefit that all system controls, including recording, are foot-operated so that the examiner can perform the examination without additional staff. Foot control of light source, camera, and video record/pause as well as the convenience of on-screen display of information allow the clinician to perform examinations unaided by staff.

Instant Examination Review

One advantage of the digital system is that examination review is instantaneous. The benefit in saved time is actually minutes per exam when compared to VCR recorded exams. The user can quickly move to the beginning, or to any frame, of the exam and play the recording. The user can select a start and stop point and play that particular segment as a loop. It is also fast and easy to compare any examination with others in the database.

Playback of Two Examinations

The key to accurate and easy assessment and comparison of patient performance over time (e.g., pre- and post-surgery) is the capability of loading two exams at once and playing each recording side by side. A unique feature of the digital video system is that two examinations can be loaded simultaneously, and the examiner can switch between each recording. Additionally, different segments of the same exam can be compared in this fashion. The digital video system provides these easy viewing comparisons.

Patient Reports

All patient and examination information is stored in industry standard formats (Microsoft Access) with templates for quick generation of reports.

Printing

There are numerous inexpensive printers with Windows™ drivers suitable for video printing. Kay offers printers for either small "video prints", or standard paper-size for printing a complete report (including images).

Sophisticated Patient Database

Kay’s system maintains a sophisticated, searchable database of patient/exam information. Patient and exam information are easily updated before or after a procedure. The clinician is provided with database fields for documenting each examination. The software allows the examiner to easily include a picture of the patient as part of the data stored with an exam.

Complete System

Recording medical-grade video in a computer requires carefully selected components to provide superior video quality. Compromised performance, such as motion artifacts due to frame dropping, is not acceptable in medical applications. All components of the Digital Strobe have been carefully considered and integrated into a complete system. No aspect of daily system usage has been neglected, from operation to system backup. The user can take advantage of Kay’s experience in selecting and integrating components for unmatched performance.

The computer contains custom AV-rated hard drives, SCSI ultra-wide interface to drives, and AV-rated cartridges. The operating system is designed for mission critical tasks (Microsoft WindowsNT Workstation 4.0). Inside the computer is a broadcast-quality video capture board, custom hardware for camera control, and video graphics support for 60-fields-per-second playback. The software has been written to facilitate ease-of-use in the clinic. With Kay’s carefully designed system, the performance required for reliable, artifact-free video capture and playback is assured.

The Concept of a Voice Lab

An emerging concept over the last ten years is the use of a multi-disciplinary team to address voice problems. This team always includes a laryngologist and a speech-language pathologist. Often it includes a voice scientist and sometimes a professional voice or singing teacher. Typically, this team uses stroboscopy and endoscopy (using flexible and rigid scopes) along with aerodynamic, perceptual, and acoustic equipment to more fully assess the vocal function. Kay provides a complete line of equipment for voice labs.

Upgrade Available

Kay’s Basic Stroboscopy and Computer-Integrated Systems can both be upgraded to the new digital video system. This is a straightforward process and is surprisingly affordable.

Videokymography Option

Videokymography (VKG) is a new technique developed by Drs. Harm Schutte and Jan Svec which captures high-speed motion without stroboscopy. This new technology is described in more detail in a separate flyer. VKG provides the ability to observe vocal fold motion that is not periodic, including voicing initiation, diplophonia, biphonia, vocal fry, creaky voice, and very aperiodic voices.

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