Spasmodic Dysphonia

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Spasmodic Dysphonia
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• Spasmodic Dysphonia is primarily characterized by
  frequent voice breaks and significant vocal
  effort

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Spasmodic Dysphonia (SD)

• Controversial etiology
• Psychologic vs. neurologic
• SD is generally considered an
• adult onset action induced focal dystonia

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What is a focal dystonia?

• Uncontrolled spasmodic muscle contractions
• Often begin in adulthood
• May be
• restricted to a few muscles (focal)
• Segmental (group of muscles)
• General (large areas of the body)
• Problems typically occur during task execution
  and appear normal at rest

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Other Examples of Focal Dystonia?

• Blepharospasm
• Writers cramp
• Torticollis (cervical dystonia)

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Evidence for a neurogenic etiology for SD

• Pts often exhibit other movement related problems
  (limb, orofacial)
• Non-medical treatment meets only limited success
• Limited evidence for neurologic differences
  between SD and normal population
• Variety of neural loci implicated
• basal ganglia, SMA

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Potential Neural Mechanisms

• Reduced neural inhibition
• Increased neural plasticity
• Abnormal sensory gating

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Spasmodic Dysphonia Other Observations

• Symptoms may increase during stress
• More likely to have had childhood measles/mumps
• No more likely to have other neurological
  conditions
• No obvious environmental patterns
• More common for those with European ancestry
• 10 report a family history

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Spasmodic dysphonia Types

• Adductor SD (ADDSD)
• Intermittent voice breaks in the middle of vowels
• Strained-strangled, effortful voice quality
• Spasmodic hyperadduction of TVFs
• Abductor SD (ABDSD)
• Abduction of true vocal folds (devoicing gesture)
• Prolonged voiceless consonants difficulty with
  voice onset following voiceless sounds
• May have breathy voice quality

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Vocal Tremor

• voice breaks, frequency modulation or amplitude
  modulation at regular intervals (5 Hz)
• Best observed during a sustained vowel task
• Tremor is a common neurologic sign
• Tremor therefore is highly suggestive of neural
  involvement
• May be associated with known neurological disease
• May be familial
• Can occur as an isolated condition
• Often co-occurs with SD ( ¼ of SD have tremor)

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Spasmodic Dysphonia Related Disorders
Epidemiology

• Prevalence of focal dystonia 295 per million
• Prevalence of SD 1 per 100,000
• Prevalence ranking for focal dystonia
• Torticollis
• Blepharospam
• SD
• Females gt Males
• ranges from 1.41 71
• ABSD less common
• 10-15 of SD

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Spasmodic Dysphonia diagnostic tasks

• Connected speech-will exhibit difficulties
• Sustained vowel
• Reduction/resolution of symptoms
• less severe than connected speech
• May have tremor 5 Hz
• Falsetto (count to 10) - Asymptomatic
• Whisper (count to 10) - Asymptomatic
• Singing (Happy Birthday) Improvement
• Pitch glide - ? symptoms at highest pitches
• Loud speech - ? symptoms for shouting

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Adductor SD diagnostic tasks

• Sentences all voiced
• ? difficulty
• Sentences high frequency voiceless
• ? difficulty
• Eighty series (e.g. count 80, 81, 82)
• ? difficulty
• Sixty series (e.g. count 60, 61, 62)
• ? difficulty
• repetitions of we vs. pea, tea, key,
  see
• we ? difficulty

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Abductor SD diagnostic tasks

• Sentences all voiced
• ? difficulty
• Sentences high frequency voiceless
• ? difficulty
• Eighty series (e.g. count 80, 81, 82)
• ? difficulty
• Sixty series (e.g. count 60, 61, 62)
• ? difficulty
• repetitions of we vs. pea, tea, key,
  see
• voiceless ? difficulty

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ADSD vs. ABSD Sentence Stimuli

• All voiced segmentselicits ADSD symptoms
• Early one morning a man and a woman were ambling
  along a one-mile lane running near rainy Island
  Avenue
• Albert eats eggs every Easter early in the a.m.

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ADSD vs. ABSD Sentence Stimuli

• Voiceless segmentselicits ABDSD symptoms
• He saw half a shape mystically cross fifty or
  sixty steps in front of his sister Kathys house.
• She sells seashells by the seashore.

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ADSD Other diagnostic tasks

• Ingressive reading of all voiced segments
• Unilateral RLN Block (lidocaine)
• Will eliminate ADDSD within several minutes of
  ipsilateral paresis/paralysis
• lasts about 20-25 minutes
• Should confirm paralysis endoscopically
• Return of pre-block symptoms after nerve block
  effects abate
• Recent evidence suggests this does not
  differentiate ADSD from MTD (Roy, et al. 2007)

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Other signs/symptoms of ADDSD

• Minimal signs of ? musculoskeletal tension
• Minimal pain, tenderness, hypertonicity
• Laryngeal elevation is in synchrony with adductor
  spasms
• No sustained response to manual circumlaryngeal
  techniques (behavioral treatment)
• Some transient improvement with laryngeal
  stabilization maneuvers (behavioral treatment)

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Distinguishing SD and MTD

• MTD
• Severity of sustained vowel often commensurate
  with connected speech
• No obvious differences between voiced and
  voiceless contexts (all contexts difficult)
• Is usually continuous and rarely intermittent (no
  islands of normal speech)
• Shows no improvement with falsetto or singing

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Distinguishing SD and MTD

• MTD
• Is associated with reported pain, tenderness
• Is not associated with tremor
• Shows sustained improvement after manual
  circumlaryngeal therapy

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Distinguishing SD and MTD

• Studies of psychologic factors and dysphonia
• MTD
• tendency toward introversion and neuroticism
• SD
• No evidence for psychological/personality factors
• There is evidence pre-post differences that may
  be related to a reaction to the problem

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Recent evidence

• If there is not a voiced-voiceless difference in
  severity, it does not necessarily exclude ADSD
  from the Dx (1/2 ADSD did not show task
  specificity in recent study)
• If there is a voiced-voiceless difference in
  severity, the likelihood of ADSD is increased

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Spasmodic Dysphonia Management

• No known cure
• Treatment aim is to control/relieve symptoms
• Patient should be educated regarding management
  options
• Advantages/disadvantages with all treatments

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Spasmodic Dysphonia Treatment options

• Behavioral
• Voice Therapy (limited benefit for moderate to
  severe ADDSD or tremor)
• Medical
• Botulinum Toxin injections (BOTOX)
• Neuropharmacological Intervention
• Surgical
• Recurrent Laryngeal Nerve Section
• Thyroplasty, myotomy etc.

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When/Who to offer voice therapy?

• During differential diagnosis (diagnostic
  therapy)
• Coexisting muscle tension dysphonia
• May extend the effect of BOTOX in ADDSD
• ABSD pts who exhibit little response to BOTOX
• Pts with mild/inconsistent symptoms of ADDSD
• BOTOX may provide too great an effect
• Trial therapy should be short term (lt 5 sessions)

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Possible Voice Therapy Techniques

• Manual circumlaryngeal therapy
• Breathy voice attack
• Pitch elevation
• Loudness reduction
• Techniques for hyperfunctional voice disorders
• resonant voice, yawn sigh, relaxation
• Inhalation voice therapy

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Medical Management BOTOX Injections

• Inject intrinsic muscles with BOTOX
• BOTOX neurotoxin that produces chemical
  denervation at neuromuscular junction
• Advantages
• Temporary
• no (known) permanent injury
• Side effects are temporary

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Botulinum Toxin (BOTOX)
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Medical Management BOTOX Injections

• Disadvantages
• Temporary
• Costly re-injection every 4 mos.
• Breathiness (7-20 days)
• Swallowing side effects (3-5 days)
• Poor predictability of patient response
• Possible buildup of resistance to injections

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Medical Management BOTOX Injections

• Who benefits most?
• Moderate to severe ADDSD
• Vocal tremor
• ABSD ?
• Patients who get questionable benefit
• Mild ADDSD
• Coexisting regional dystonia

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BOTOX Injections Procedures

• Peroral
• Injection via oral cavity
• Uses less toxin
• No EMG verification
• Percutaneous
• Through the neck tissue
• Uses EMG verification

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BOTOX Injection Sites

• ADDSD
• TA (most frequent)
• LCA
• Both

• ABSD
• PCA
• must be percutaneous
• technically demanding
• Maybe CT
• Vocal tremor
• TA, sternohyoid and thyrohyoid
• injections more likely bilateral

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BOTOX Injection Dosage

• Bilateral
• 2.5 units per side
• Unilateral
• 15 units
• Unilateral considered superior, with longer
  lasting effects

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Surgical ManagementRecurrent Nerve Resection

• Advantages
• Potential long term benefit (40)
• Disadvantages
• Unpredictable side effects
• Symptom return (up to 60)
• Permanent unilateral paralysis
• Controversial
• Patient types benefited
• Focal severe ADDSD

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Other Neurpharmacological Intervention

• Propanolol (Inderal) for voice tremor
• Artane (anticholinergic) for ABSD
• Baclofen muscle relaxant for ADDSD
• Disadvantages
• Limited voice change
• Adjunct role at best
• No controlled studies to demonstrate effectiveness

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Selected CNS diseases

• ALS
• Parkinsons Disease
• Myasthenia gravis