The purpose was to examine whether physiological changes can be found in laryngeal muscles following repeated treatment with botulinum toxin injections in spasmodic dysphonia. Seven patients whose treatment consisted of multiple unilateral thyroarytenoid injections were examined more than 6 months following their most recent botulinum toxin injection by fiberoptic laryngoscopy and electromyography. Comparisons were made between injected and contralateral noninjected muscles' motor unit characteristics, muscle activation patterns, and vocal fold movement characteristics. The results demonstrated that motor unit characteristics differed between injected and noninjected muscles and that these differences were greater in patients less than 12 months since last injection. Motor unit duration differences were reduced and motor unit amplitude and numbers of turns were increased in muscles sampled over 1 year after injection. These results suggest that while the physiologic effects of botulinum toxin are reversible, the reinnervation process continues past 12 months following injection.
IzdebskiKDedoHHBolesL. Spastic dysphonia: A patient profile of 200 cases. Am J Otolaryngol1984; 5: 7–14.
2.
FinitzoTPoolKDFreemanFJ. Spasmodic dysphonia subsequent to head trauma. Arch Otolaryngol Head Neck Surg1987; 113: 1107–10.
3.
BlitzerABrinMFFahnSLovelaceRE. Clinical and laboratory characteristics of focal laryngeal dystonia: Study of 110 cases. Laryngoscope1988; 98: 636–40.
4.
LudlowCLConnorNP. Dynamic aspects of phonatory control in spasmodic dysphonia. J Speech Hear Res1987; 30: 197–206.
5.
ParnesSMLavoratoASMyersEN. Study of spastic dysphonia using videofiberoptic laryngoscopy. Ann Otol Rhinol Laryngol1978; 87: 322–6.
6.
BlitzerALovelaceREBrinMFFahnSFinkME. Electromyographic findings in focal laryngeal dystonia (spastic dysphonia). Ann Otol Rhinol Laryngol1985; 94: 591–4.
7.
SchaeferSDRoarkRMWatsonBC. Multichannel electromyographic observations in spasmodic dysphonia patients and normal control subjects. Ann Otol Rhinol Laryngol1992; 101: 67–75.
8.
LudlowCLBakerMNauntonRFHallettM. Intrinsic laryngeal muscle activation in spasmodic dysphonia. In: BeneckeRConradBMarsdenCD, eds. Motor disturbances. Orlando, Fla: Academic Press, 1988: 119–30.
9.
WatsonBCSchaeferSDFreemanFJDembroskiJKondraskeGRoarkR. Laryngeal electromyographic activity in adductor and abductor spasmodic dysphonia. J Speech Hear Res1991; 34: 473–82.
10.
Van PeltFLudlowCLSmithPJ. Comparison of muscle activation patterns in adductor and abductor spasmodic dysphonia. Ann Otol Rhinol Laryngol1994; 103: 192–200.
11.
National Institutes of Health Consensus Development Conference Consensus Statement. Clinical use of botulinum toxin. Arch Neurol1991; 48: 1294–8.
12.
LudlowCL. Treatment of speech and voice disorders with botulinum toxin. JAMA1990; 264: 2671–5.
13.
BlitzerABrinMF. Laryngeal dystonia: A series with botulinum toxin therapy. Ann Otol Rhinol Laryngol1991; 100: 85–9.
14.
JankovicJSchwartzKDonovanDT. Botulinum toxin treatment of cranial-cervical dystonia, spasmodic dysphonia, other focal dystonias and hemifacial spasm. J Neurol Neurosurg Psychiatry1990; 53: 633–9.
15.
DuttonJJBuckleyEG. Botulinum toxin in the management of blepharospasm. Arch Neurol1986; 43: 380–2.
CohenLGHallettMGellerBDHochbergF. Treatment of focal dystonias of the hand with botulinum toxin injections. J Neurol Neurosurg Psychiatry1989; 52: 355–63.
19.
LudlowCLBagleyJAYinSGKodaJ. A comparison of different injection techniques in the treatment of spasmodic dysphonia with botulinum toxin. J Voice1992; 6: 380–6.
20.
ZwirnerPMurryTWoodsonGE. A comparison of bilateral and unilateral botulinum toxin treatments for spasmodic dysphonia. Eur Arch Otorhinolaryngol1993; 250: 271–6.
21.
LangeDJ. Systemic effects of botulinum toxin. In: JankovicJHallettM, eds. Therapy with botulinum toxin. New York, NY: Marcel Dekker, 1994: 109–18.
22.
BorodicGEFerranteRJPearceLBAldersonK. Pharmacology andhistology of the therapeutic application of botulinum toxin. In: JankovicJHallettM, eds. Therapy with botulinum toxin. New York, NY: Marcel Dekker, 1994: 119–57.
23.
HarrisCPAldersonKNebekerJHoldsJBAndersonRL. Histologic features of human orbicularis oculi treated with botulinum A toxin. Arch Ophthalmol1991; 109: 393–5.
24.
CohenSRThompsonJWCamilonFSJr. Botulinum toxin for relief of bilateral abductor paralysis of the larynx: Histologic study in an animal model. Ann Otol Rhinol Laryngol1989; 98: 213–6.
25.
BorodicGEFerranteR. Effects of repeated botulinum toxin injections on orbicularis oculi muscle. J Clin Neuro Ophthalmol1992; 12: 121–7.
26.
AldersonKHoldsJBAndersonRL. Botulinum-induced alteration of nerve-muscle interactions in the human orbicularis oculi following treatment for blepharospasm. Neurology1991; 41: 1800–5.
27.
HoldsJBAldersonKFoggSGAndersonRL. Motor nerve sprouting in human orbicularis muscle after botulinum A injection. Invest Ophthalmol Vis Sci1990; 31: 964–7.
28.
ShaariCMGeorgeEWuBLBillerHFSandersI. Quantifying the spread of botulinum toxin through muscle fascia. Laryngoscope1991; 101: 960–4.
29.
GeorgeEFZimblerMWuB-LBillerHFSandersI. Quantitative mapping of the effect of botulinum toxin injections in the thyroarytenoid muscle. Ann Otol Rhinol Laryngol1992; 101: 888–92.
30.
HiranoMOhalaJ. Use of hooked-wire electrodes for electromyography of the intrinsic laryngeal muscles. J Speech Hear Res1969; 12: 362–73.
31.
ChanaudCMLudlowCL. Single motor unit activity of human intrinsic laryngeal muscles during respiration. Ann Otol Rhinol Laryngol1992; 101: 832–40.
32.
LindestadP-AFritzellBPerssonA. Evaluation of laryngeal muscle function by quantitative analysis of the EMG interference pattern. Acta Otolaryngol (Stockh)1990; 109: 467–72.
33.
LindestadP-AFritzellBPerssonA. Quantitative analysis of laryngeal EMG in normal subjects. Acta Otolaryngol (Stockh)1991; 111: 1146–52.
34.
KnutssonEMartenssonAMartenssonB. The normal electromyogram in human vocal muscles. Acta Otolaryngol (Stockh)1969; 68: 526–36.
35.
Faaborg-AndersenK. Electromyographic investigation of intrinsic laryngeal muscles in humans. Acta Physiol Scand [Suppl]1957; 41(suppl 140).
36.
KimuraJ. Electrodiagnosis in diseases of nerve and muscle: principles and practice. Philadelphia, Pa: FA Davis, 1983: 323.
37.
LoebGEGansC. Electromyography for experimentalists. Chicago, Ill: The University of Chicago, 1986.
38.
AdamsSGHuntEJCharlesDALangeAE. Unilateral versus bilateral botulinum toxin injections in spasmodic dysphonia: Acoustic and perceptual results. J Otolaryngol1993; 22: 171–5.
39.
BischoffCMacHetanzJConradB. Is there an age-dependent continuous increase in the duration of the motor unit action potential?Electroencephalogr Clin Neurophysiol1991; 81: 304–11.
40.
SaccoGBuchthalPRosenfalckP. Motor unit potentials at different ages. Arch Neurol1962; 6: 44–51.
41.
BuchthalFPinelliPRosenfalckP. Action potential parameters in normal human muscles and their physiological determinants. Acta Physiol Scand1954; 32: 219–29.
