Examination of the larynx: research methods

The primary goal of laryngeal examination is to quickly and accurately differentiate functional voice disorders from organic changes in the mucosa and underlying structures, determine the cause of hoarseness, a "globus sensation," noisy breathing, or episodes of suffocation, and, if necessary, obtain immediate morphological data. The modern approach combines a clinical interview, laryngeal visualization, instrumental voice assessment, and, when indicated, radiographic imaging or laryngeal electromyography. This combined approach reduces diagnostic delays and directs patients to targeted therapy. [1]

The key trigger for evaluation is dysphonia lasting 4 weeks or longer, or earlier presentation for "red flags," such as in smokers, pain, dysphagia, hemoptysis, or severe respiratory stridor. Guidelines emphasize early laryngeal imaging to avoid unnecessary prescription of empirical medications and to detect serious pathology. [2]

A visual examination is performed using a flexible endoscope through the nose in a clinical setting, with stroboscopy added as needed to assess vocal fold vibration. In questionable cases, advanced contrast illumination technologies and high-speed video monitoring are used, which increase sensitivity to early or microfunctional abnormalities. [3]

Evaluation is never limited to a "picture." For completeness, perceptual, acoustic, and aerodynamic voice parameters are collected using standardized protocols, which helps compare dynamics and objectively document the treatment effect, especially for professional voices. [4]

Basic methods of visualization of the larynx

Flexible nasopharyngolaryngoscopy has become a first-line method: a thin endoscope is used through the nose to image the entire supraglottic region and larynx during natural breathing and speech tests. This allows for assessment of movement symmetry, glottal closure, contact lesions, and suspected areas, as well as video recording for subsequent analysis. [5]

Stroboscopy synchronizes light with the vibration frequency and displays the mucosal waveform, periodicity, and amplitude, which is critical for diagnosing hidden vibration disorders and monitoring the results of phoniatric therapy. Guidelines recommend incorporating stroboscopy in cases of persistent dysphonia and in professional voices. [6]

Narrowband imaging, known as narrowband illumination, enhances the contrast of superficial vessels and helps identify dysplasia and early cancer. The European Laryngological Society has proposed a classification of vascular patterns, and validation has shown high reproducibility and utility for targeted biopsy. [7]

High-speed videoendoscopy complements stroboscopy when phonation is unstable or when second-by-second analysis of atypical oscillations is required. New studies indicate an increase in the proportion of recordings suitable for objective evaluation and the potential for integration with analysis algorithms. [8]

Table 1. Laryngeal imaging: what it shows and when to choose

Method	What does he see best?	When is it preferable?	Restrictions
Flexible laryngoscopy	Real-time anatomy and mobility	First line in the office, dynamic tests	Mucosal anesthesia and experience are needed
Stroboscopy	Mucous wave, periodicity, symmetry	Persistent dysphonia, therapy monitoring	Requires stable phonation
Narrow Band Imaging	Vascular pattern, areas of suspicion	Triage and targeted biopsy	Does not replace histology
High-speed video	Atypical and irregular fluctuations	Complex cases, scientific analysis	Availability and labor intensity

Source: clinical guidelines and validation studies. [9]

Instrumental Voice Assessment: What is Measured and How to Use the Results

Perceptual assessment includes standardized scales, such as quality, pitch, loudness, effort, and intelligibility. Its purpose is to capture the clinical expressiveness of symptoms and their impact on communication. The consensus of the European Laryngological Society and the Union of European Phoniatricians establishes a common descriptive language for clinical and research use. [10]

Acoustic metrics reflect frequency and amplitude variability, noise floor, pitch range, and peak phonation time. Standardized recording protocols, controlled conditions, and the use of validated metrics are recommended to improve data comparability between visits and centers. [11]

Aerodynamic measurements assess flow and pressure during phonation and help to understand mechanisms of impairment, such as leakage or hyperfunction. Combining perceptual, acoustic, and aerodynamic data improves the accuracy of phenotyping and the choice of treatment. [12]

For professional voices, the set is expanded with special stress tests with video recording, since microfunctional deviations often only manifest themselves in "working" mode. A standardized report facilitates communication with the speech therapist and oncologist and speeds up decision-making. [13]

Table 2. Frequently used voice evaluation parameters

Block	Examples of parameters	Practical meaning
Perceptual	Quality, pitch, volume, effort	Basic clinical voice "vital"
Acoustic	Frequency and amplitude variability, noise fraction, range	Objectification of dysphonia and dynamics
Aerodynamic	Flow, subglottic pressure, phonation time	Analysis of the mechanics of phonation and leakage

Source: Consensus and instrumental assessment protocols. [14]

Radiation and ultrasound imaging: where they are needed

Computed tomography and magnetic resonance imaging are used for detailed anatomical assessment of suspected tumors, extramucosal invasion, cartilage damage, and fixation of underlying structures. Positron emission tomography, in combination with computed tomography, complements staging by providing metabolic information and mapping distant lesions. The choice of method is based on the clinical objective and current criteria for validation. [15]

A special technique, "phonation" computed tomography, helps visualize vocal fold paralysis and signs of neurogenic damage, increasing diagnostic confidence compared to conventional imaging at rest. This is useful when clinical mobility tests are in doubt. [16]

Transcutaneous laryngeal ultrasonography is increasingly used to screen vocal fold mobility in children and adults following thyroid or tracheal surgery, as well as after extubation. Current studies demonstrate high accuracy in trained teams and good tolerability. Laryngoscopy remains the standard of confirmation. [17]

Ultrasound is also useful for quantifying the range of motion and area of the glottis, which facilitates recovery monitoring and intervention decisions. This method is indispensable in cases where avoiding radiation and sedation is important. [18]

Table 3. Radiation and ultrasound imaging for laryngeal pathology

Method	Task	When it is especially useful	Note
Computed tomography	Anatomy, cartilage, prevalence	Suspected tumor, stenosis, trauma	Fast and affordable
Magnetic resonance imaging	Soft tissues, nerves	Detailing of soft tissue structures	Longer in time
Positron emission tomography with computed tomography	Metabolic activity	Staging and metastasis detection	Complements the anatomy
Phonation computed tomography	Mobility during phonation	Suspected paralysis	Special protocol
Laryngeal ultrasound	Mobility, gap area	Pediatrics, postoperative, post-extubation disorders	Screening and monitoring

Source: Clinical guidelines and accuracy studies.[19]

Laryngeal electromyography: when it decides the outcome

Laryngeal electromyography assesses the bioelectrical activity of the laryngeal muscles and helps differentiate recurrent laryngeal nerve neuropathy from arytenoid cartilage tethering, predict the restoration of mobility, and determine the timing of injection medialization. This is especially important in unilateral paralysis following thyroid and cardiac surgery. [20]

Studies show that the presence of denervation potentials and the nature of recruitment correlate with the likelihood of spontaneous restoration of vocal fold movement. This allows for personalized timing of active interventions and avoids both premature and delayed interventions. [21]

The method requires specialized experience, but provides unique information where visual examination and radiographic diagnostics fail to provide a prognostic answer. Algorithms consider it a complement to endoscopy and acoustic testing, not a replacement. [22]

In recent years, studies have begun to use quantitative metrics, increasing the reproducibility of findings and integration with clinical scales. This makes electromyography part of the evidence-based management of patients with mobility impairments. [23]

Table 4. Laryngeal electromyography: where it helps and what is responsible

Clinical question	What does electromyography show?	Practical conclusion
Is it neuropathy or fixation?	Denervation, recruitment, synkinesis	Selection of tactics and timing of interventions
Is there a chance for recovery?	Signs of reinnervation	Voice observation or correction plan
Is early medialization necessary?	Degree of muscle damage	Decision on temporary injections
Why does dysphonia persist?	Bioelectrical picture during normal endoscopy	Correction of rehabilitation

Source: consensus and clinical trials.[24]

Indications, preparation and relative contraindications

Indications include persistent dysphonia, suspected neoplasm, noisy breathing and stridor, post-intubation symptoms, follow-up after laryngeal and thyroid surgery, and occupational complaints of decreased vocal endurance. Patients with "red flags" are examined without delay. [25]

Preparation for flexible endoscopy includes a vasoconstrictor spray and local anesthetic, information about possible numbness, and a recommendation to refrain from eating and drinking hot drinks for approximately 30-60 minutes after the procedure. For planned biopsies, antithrombotic medications and safety precautions are discussed in advance. [26]

Relative contraindications to in-office examination include severe intolerance to endoscopy, uncontrolled coagulopathy, and unstable cardiorespiratory conditions. In such cases, the examination is transferred to the operating room, where airway management and hemostasis monitoring are possible. [27]

When infectious risks arise, validated optical processing protocols are followed: pre-cleaning, manual cleaning, high-level disinfection, rinsing, drying, and storage. Surveillance audits confirm safety when all steps are performed correctly. [28]

Table 5. Indications and relative contraindications

Indications	Examples	Relative contraindications	Tactics
Dysphonia ≥ 4 weeks	Nodules, polyps, paralysis	Coagulopathy	Transfer to the operating room, correction
Stridor and noisy breathing	Subglottic stenosis, laryngomalacia	Unstable states	Team training and monitoring
Suspected neoplasia	Leukoplakia, dysplasia	Intolerance to endoscopy	Sedation and experienced operator
After surgery and intubation	Hoarseness, aspiration	Active mucosal infection	Postponement until stabilization

Source: relevant guidelines and positions of societies. [29]

Safety, infection control and environmental sustainability

Flexible laryngoscopy is generally well tolerated. Common mild complications include discomfort, sneezing, and moderate nosebleeds. Serious complications are extremely rare when monitoring and preparation standards are followed. Standards for endoscope reprocessing and personnel training are key to reducing risks. [30]

Current documentation confirms that high-level disinfection, when strictly followed, provides comparable effectiveness to automatic washes, provided the manual cleaning and drying steps are followed. The choice between disposable and reusable optics takes into account safety, waste, and water consumption. [31]

General endoscopy guidelines emphasize the need for competent personnel to be available for unscheduled procedures and prepared for immediate processing to maintain the infection control chain. This reduces the likelihood of organizational failures and protects patients. [32]

During epidemic surges in respiratory infections, adherence to treatment protocols and personnel protective equipment prevented clusters of transmission in outpatient laryngoscopy, as confirmed by audits. This argues for maintaining routine diagnostics with reasonable precautions. [33]

Table 6. Common and rare safety events and their prevention

Event	How often	Prevention
Discomfort and cough	Often	Mucosal anesthesia, delicate technique
Nosebleed	Sometimes	Decongestant spray, choose a wider stroke
Vasovagal reaction	Rarely	Patient preparation, observation
Allergic reaction to anesthetic	Very rarely	Collection of anamnesis, dose control

Source: observational studies and guidelines.[34]

Special situations: children, professional voices, oncology route

In pediatrics, flexible endoscopy is complemented by laryngeal ultrasound for motility screening, reducing the need for invasive procedures. Coordination of the results of the two methods increases diagnostic confidence and expedites decision-making in a format that is safe for the child. [35]

For professional voices, stroboscopy and an extensive set of acoustic tests, stress test recording, and precise protocoling are mandatory to accurately assess microfunctional deviations and the response to rehabilitation. A consensus of experts sets the standard for these assessments. [36]

In the oncology workup, narrow-band imaging helps select a target area for biopsy, while radiation imaging determines the depth of invasion and extent of disease. Combining these methods accelerates staging and treatment initiation. [37]

Following difficult intubation and extubation, ultrasound provides early detection of post-procedural mobility dysfunction, allowing prevention of aspiration events and adjustment of nutrition while function is restored.[38]

Table 7. Accents in special groups

Group	What is important to add to the standard?
Children	Ultrasound motility screening, gentle protocols
Professional voices	Stroboscopy, stress tests, detailed acoustics
Oncology route	Narrow band imaging and targeted biopsy, staging
After intubation	Ultrasound monitoring of motility and measures to prevent aspiration

Source: Clinical guidelines and group studies. [39]

Interpreting the results and next steps

A standardized report should describe anatomy, mobility, signs of contact lesions, vibration measurements by stroboscopy, vascular patterns by narrow-band imaging, and acoustic test results. This structure facilitates interdisciplinary discussion and comparison of dynamics. [40]

If suspicious areas are identified, targeted biopsy and imaging are planned for staging. If morphology is negative and there is a high clinical probability of pathology, a repeat targeted biopsy or alternative approach is discussed. Decisions are made in a multidisciplinary manner. [41]

In cases of vocal fold mobility impairment, laryngeal electromyography is considered to predict recovery and determine the timing of voice correction or surgical interventions. This reduces the risk of unnecessary delays and improves quality of life. [42]

Finally, the patient receives clear recommendations on next steps, timing of follow-up examinations and repeat voice measurements, which translates the diagnosis into a manageable route with clear checkpoints. [43]

Table 8. Typical scenarios and tactics after examination

Find	The next step	Target
Functional disorder without organic causes	Speech therapy, control stroboscopy	Restoring voice quality
Suspected neoplasia	Targeted biopsy, staging	Quick start of treatment
Vocal fold paralysis	Electromyography, correction plan	Optimization of intervention time
Post-intubation complaints	Ultrasound monitoring, rehabilitation	Prevention of aspiration and restoration of function

Source: Guidelines and consensus documents. [44]