Voice Disorders on the Praxis SLP: Pathology, Assessment, EBP

Voice disorders are a Big 9 area and show up on the 5331 in three predictable ways: differential diagnosis (organic vs. functional vs. neurogenic), instrumental assessment interpretation, and evidence-based therapy selection. Here's the focused review.

Organic voice pathology — lesion identification

• Vocal fold nodules: bilateral, symmetric, junction of anterior 1/3 and posterior 2/3. Cause: vocal abuse/misuse (yelling, throat clearing, singing without training). Common in children (teachers' kids), women aged 20–50.
• Vocal fold polyps: usually unilateral, can be sessile or pedunculated. Cause: single traumatic event or chronic smoking. Often require surgery.
• Vocal fold cysts: unilateral, sub-epithelial, do not resolve with voice therapy alone — require surgical excision.
• Reinke's edema (polypoid degeneration):smoker's voice. Bilateral swelling of the superficial lamina propria. Low pitch, hoarse.
• Contact ulcers/granulomas: posterior third, vocal process of arytenoid. Cause: reflux, intubation, hard glottal attack.
• Laryngeal papilloma: HPV-related. Recurrent, requires surgical removal.

Neurogenic voice disorders

• Unilateral vocal fold paralysis: CN X (recurrent laryngeal nerve) injury — often post-thyroidectomy or cardiac surgery. Breathy voice, weak cough, aspiration risk.
• Spasmodic dysphonia (adductor): focal dystonia. Strained, strangled voice with voice breaks on vowels. First-line: Botox injections. Voice therapy supports but does not cure.
• Spasmodic dysphonia (abductor): breathy voice breaks on voiceless consonants.
• Parkinson's hypokinetic dysphonia: reduced loudness, monopitch, monoloudness, breathiness. First-line therapy: LSVT LOUD.
• Essential tremor of voice: rhythmic 4–7 Hz pitch/loudness modulation, worse on sustained /a/.

Functional voice disorders

• Muscle tension dysphonia (MTD): excessive laryngeal/paralaryngeal muscle activation without structural pathology. Voice therapy is first-line.
• Puberphonia (mutational falsetto): post-pubertal male continues to speak in high pitch. Voice therapy highly effective.
• Conversion aphonia: sudden whispered voice, normal cough (indicates intact structure).

Instrumental assessment — what each tool tells you

• Videostroboscopy: gold standard for visualizing vocal fold vibration. Assesses closure, symmetry, mucosal wave, amplitude.
• Acoustic analysis: fundamental frequency (F0), jitter (frequency perturbation), shimmer (amplitude perturbation), HNR (harmonics-to-noise ratio).
• Aerodynamic: maximum phonation time (MPT — normal ≥ 15 sec adults), subglottal pressure, mean airflow.
• Perceptual (CAPE-V or GRBAS): Grade, Roughness, Breathiness, Asthenia, Strain. Always paired with instrumental.

Evidence-based voice therapy approaches

• Vocal hygiene: hydration, reduced yelling/throat clearing, reflux management. Foundation, rarely sufficient alone.
• Resonant voice therapy (LMRVT): forward-focused, "buzzy" sensation. Good for MTD and nodules.
• Vocal function exercises (VFEs): Stemple's 4-exercise program. Rebuilds laryngeal muscle balance.
• LSVT LOUD: Parkinson's. High effort ("think LOUD"), 4x/week × 4 weeks, intensive.
• SOVT (semi-occluded vocal tract) exercises: straw phonation, lip trills. Reduces impact stress, useful across many diagnoses.
• Circumlaryngeal massage: MTD.

Referral musts

Any hoarseness > 2 weeks without obvious cause = ENT referral for laryngoscopy BEFORE voice therapy. This is an exam favorite. The SLP does not diagnose lesions; the ENT does.