From the Guidelines
Neurological causes of voice hoarseness are primarily attributed to conditions such as vocal fold paralysis, spasmodic dysphonia, essential tremor, Parkinson’s disease, amyotrophic lateral sclerosis, and multiple sclerosis, as highlighted in the clinical practice guideline: hoarseness (dysphonia) (update) executive summary 1. The most common neurological conditions causing hoarseness include:
- Vocal cord paralysis from stroke
- Brain tumors affecting the brainstem
- Parkinson's disease
- Multiple sclerosis
- Myasthenia gravis
- Amyotrophic lateral sclerosis (ALS) Iatrogenic injury during neck or chest surgery can damage the recurrent laryngeal nerve, leading to vocal cord dysfunction. Compression of these nerves by tumors, particularly lung cancer affecting the left recurrent laryngeal nerve, can cause hoarseness. Essential tremor and other movement disorders may affect voice quality through laryngeal muscle tremors. Guillain-Barré syndrome can cause temporary vocal cord weakness during its acute phase. Treatment depends on the underlying cause and may include speech therapy, medication for the primary condition, or surgical interventions like vocal cord medialization, as recommended in the clinical practice guideline: hoarseness (dysphonia) (update) 1. Voice therapy is often beneficial regardless of cause. Patients with unexplained persistent hoarseness should undergo laryngoscopy and neurological evaluation to identify the specific cause and determine appropriate treatment. For patients with spasmodic dysphonia, botulinum toxin injections are a recommended treatment option, as supported by multiple double-blind, randomized, placebo-controlled trials 1.
From the Research
Neurological Causes of Voice Hoarseness
- Neurological diseases can cause voice disturbances, including hoarseness, due to alterations in the corticospinal pathway, cerebellum, basal ganglia, and upper and/or lower motoneurons 2
- Movement disorders such as Parkinson's disease, essential tremor, and spasmodic dysphonia can lead to voice disturbances, including hoarseness 2, 3
- Parkinson's disease is characterized by voice changes, including hoarseness, which can be an early sign of motor impairment 3
- Other neurological diseases, such as myasthenia gravis, can also cause voice disturbances, including hoarseness, especially when combined with other conditions like Parkinson's disease 4
- The CD40-CD40L interaction plays a role in neuroinflammatory responses in various neurological diseases, including Parkinson's disease and myasthenia gravis, which can potentially contribute to voice hoarseness 5
Specific Neurological Conditions
- Parkinson's disease: characterized by voice changes, including hoarseness, due to rigidity or bradykinesia of the laryngeal muscles 3
- Myasthenia gravis: can cause voice disturbances, including hoarseness, especially when combined with other conditions like Parkinson's disease 4
- Essential tremor and spasmodic dysphonia: can lead to voice disturbances, including hoarseness 2
Diagnostic and Therapeutic Approaches
- Voice examination using ear, nose & throat examination, endoscopy, and videorecording of laryngeal movements, acoustic analysis, electroglottography, laryngeal electromyography, and aerodynamic measures can be useful in diagnosing neurological causes of voice hoarseness 2
- Treatment of underlying neurological conditions, such as Parkinson's disease and myasthenia gravis, can help alleviate voice hoarseness 3, 4