Imaging of the larynx--extending the use of stroboscopy-related techniques

ROC Analysis Cut-off Points of Hellenic Voice Handicap Index for Neurogenic Voice Disorders Patients: an Exploratory Study

OBJECTIVE

The inclusion of subjective methods for evaluating Voice Disorders is proven an essential factor for diagnosis as these methods include self-reported questionnaires (eg, Voice Handicap Index-VHI) for everyday clinical practice. In turn, by obtaining cut-off scores of self-perceived questionnaires intended for assessment procedures of different voice disorders (eg, patients with neurological problems), the clinicians might be helped toward finding their patients' needs leading to better monitoring, and treatment suggestions. Consequently, the purpose of this study was to estimate the cut-off scores for the Greek VHI relevant to patients with neurogenic voice disorders.

METHODS

Ninety subjects participated in this research. Sixty-six of them served as the control group while the remaining 24 patients exhibited Neurogenic Voice Disorders (eg, spasmodic dysphonia or vocal fold paralysis). They filled in the VHI and the Voice Evaluation Template. All participants were examined with the use of video laryngeal endoscopy and stroboscopy.

RESULTS

The analysis revealed higher medians in all domains (of the VHI) for the patients compared to the control group. The cut-off points were estimated at the values of 24.50 (Total Score-AUC 0.932, P = 0.000), 9.00 (Functional Domain-AUC 0.917, P = 0.000), 10.00 (Physical Domain-AUC 0.948, P = 0.000), and 9.00 (Emotional Domain-AUC 0.830, P = 0.000).

CONCLUSION

The estimated cut-off scores are in agreement with previous studies. These scores could probably used to enhance therapeutic monitoring of patients who suffer from neurogenic voice disorders. This study underlines the importance of considering different cutoff points for individuals with voice disorders due to diverse neurogenic etiologies.

Preliminary Evaluation of Stroboscopy System Using Multiple Light Sources for Observation of Pathological Vocal Fold Oscillatory Pattern

Objectives:

Laryngostroboscopy is used to check the oscillatory patterns of the vocal folds. However, the use of one single flash timing cannot give a clear view of abnormal vocal fold oscillations that have multiple fundamental frequencies. Visualization of such complex vocal fold movements will be helpful in the diagnosis of diplophonia, a pathological condition in which the vocal folds produce multiple tones at the same time.

Methods:

We developed a new stroboscopy-based technique using multiple light-emitting diodes (LEDs) and image analysis. Specific flash timings for each LED, suitable for accurate visualization, were determined on a computer according to an algorithm based on frequency analysis. The image analysis extracted the necessary parts of the captured images to yield a clear slow-motion view of the oscillations. The series of visualization procedures took advantage of the narrow-spectrum light property of LEDs, thereby yielding a degradation-free picture.

Results:

Feasibility tests using a mechanical vocal fold model demonstrated that this computer-assisted system allows observation of the pathological oscillatory patterns as one single video. They would not be clearly visualized by conventional stroboscopy.

Conclusions:

Because of its relatively simple use and inexpensive construction, the proposed technique can become one potential option for clinical assessment of pathological vocal fold oscillations.

[The significance of videostroboscopy in laryngological practice]

The assessment of laryngeal pathology and voice dysfunction requires knowledge of anatomy and physiology as well as thorough understanding of the biomechanical (non)linear behaviour of vocal fold vibration. Videostroboscopy adds useful information to voice assessment, which always includes perceptual voice assessment and endoscopy of the larynx. Videostroboscopy can help in differentiating between benign vocal fold lesions, invasive processes, vocal fold scarring and functional disorders. Videostroboscopic evaluation can be improved by using different endoscopes and specific evaluation manoeuvres.