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Non-contact optical sensing of vocal fold paralysis using speckle pattern analysis
Doron Duadi1, Omri Frige2, Alon Tzroya1
1Faculty of Engineering and Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan, 529002, Israel.
Biomedical Optics Express
|November 26, 2025
Summary
A novel non-contact optical method uses laser speckle analysis to detect vocal fold paralysis (VFP). This technique accurately identifies VFP by analyzing voice amplitude asymmetry, offering a promising diagnostic tool.
Area of Science:
- Medical Diagnostics
- Optical Sensing Technologies
- Speech Pathology
Background:
- Vocal fold paralysis (VFP) impairs vocal fold movement, often due to surgical nerve damage.
- Current diagnostics require specialized physicians and endoscopic exams, limiting accessibility.
- There is a need for non-invasive, accessible VFP diagnostic methods.
Purpose of the Study:
- To develop and validate a non-contact optical sensing method for VFP identification.
- To assess the feasibility of using speckle pattern analysis for VFP diagnosis.
- To differentiate between healthy individuals and VFP patients using optical measurements.
Main Methods:
- Utilized a non-contact optical sensing approach with external laser illumination.
- Captured and analyzed laser speckle patterns from vocal folds using a camera.
- Employed spectral analysis with sliding window scanning to extract amplitude peaks.
- Conducted clinical measurements on 10 subjects (3 healthy, 7 VFP patients).
Main Results:
- Identical bilateral voice frequencies were observed in all subjects.
- Significant vocal fold amplitude asymmetry was detected in VFP patients.
- Healthy subjects showed amplitude ratios near 1; VFP patients exhibited ratios <0.5 (right-sided) or >2 (left-sided).
Conclusions:
- The proposed speckle pattern analysis method effectively detects and localizes vocal fold paralysis.
- This non-invasive technique offers real-time assessment and potential for widespread clinical implementation.
- Optical sensing provides a valuable alternative to traditional endoscopic VFP diagnostics.
