1/10. A new electromyographic definition of laryngeal synkinesis. Laryngeal synkinesis involves the misdirected reinnervation of an injured recurrent laryngeal nerve to vocal fold abductor and adductor musculature. The resultant laryngeal dyscoordination can cause vocal fold immobility and airway compromise. Although this entity is sometimes considered in the differential diagnosis, it is only demonstrable with laryngeal electromyography (EMG). We propose a new EMG definition of synkinesis to assist in its identification during workup of vocal fold immobility. A retrospective chart review from 1992 to 1997 in the voice disorders Clinic identified 10 patients with laryngeal synkinesis. Five patients had bilateral immobility, and 5 had unilateral immobility. Monopolar EMG was performed on all patients. Fine-wire EMG was performed when monopolar EMG did not elucidate the cause of the immobility. The EMG studies revealed synkinetic reinnervation in all subjects. On the basis of the EMG results, 7 of the 10 patients were treated with botulinum toxin to weaken the undesired reinnervation. Three of the 7 patients had benefit from this therapy. Laryngeal synkinesis should be considered as part of the differential diagnosis of vocal fold immobility. Awake laryngeal EMG is the only method to demonstrate synkinesis of the larynx. The diagnosis of synkinesis is clinically significant in cases of immobility to identify patients who might benefit from botulinum toxin therapy. Additionally, the presence of synkinesis in cases of unilateral immobility may be a contraindication to laryngeal reinnervation procedures. The benefit of botulinum toxin therapy is likely greater in the treatment of bilateral as opposed to unilateral immobility. ( info) |
2/10. Treatment of aberrant facial nerve regeneration with botulinum toxin A. PURPOSE: To assess the effect and efficacy of botulinum toxin type A (BTX-A) at reducing and maintaining eyelid synkinesia in aberrant facial nerve regeneration, while concurrently observing for the presence of side effects to differing treatment doses. methods: A prospective interventional study of five patients with eyelid synkinesia resulting from aberrant regeneration of the facial nerve. patients were treated with injections of either 120, 80 or 40 units of BTX-A (Dysport) into the orbicularis oculi. Objective and subjective reduction in synkinesia, maintenance of response and presence of side effects were recorded. RESULTS: All five patients had improvement of the synkinesia with BTX-A treatment. Lower doses were found to be as effective as higher doses. Mean duration of abolished synkinesia was three months. Two patients developed a ptosis which resolved spontaneously. None of the patients treated with the lowest dose of 40 units developed a ptosis. CONCLUSION: Low-dose BTX-A has a lower incidence of ptosis and is effective in the treatment of aberrant facial nerve regeneration. ( info) |
3/10. Dominance of ipsilateral corticospinal pathway in congenital mirror movements. OBJECTIVE: To clarify the mechanism of congenital mirror movements. DESIGN: The triple stimulation technique (TST) and the silent period were used to investigate a patient with congenital mirror movements. The TST was used to calculate the ratio of ipsilateral to contralateral corticospinal tracts from the two hemispheres to the spinal motor neurones. RESULTS: transcranial magnetic stimulation over unilateral M1 induced larger ipsilateral than contralateral motor evoked potentials on both sides. Only 9% of spinal motor neurones innervating the abductor digitorum minimi were excited by contralateral primary motor cortex (M1) stimulation, while 94% were excited by the ipsilateral M1 stimulation. The silent period was examined during mirror movements and with voluntary contraction of the right first dorsal interosseus mimicking mirror movements. Left M1 stimulation (through the crossed corticospinal tract) did not show any difference in silent period between the two conditions, while right M1 stimulation (through the uncrossed tract) caused a longer silent period during mirror movements than during voluntary contractions. CONCLUSIONS: The results suggest that mirror movements may be caused by a strong connection between ipsilateral M1 and the mirror movements conveyed through a dominant ipsilateral corticospinal pathway. ( info) |
4/10. Congenital oculomotor nerve synkinesis associated with fetal retinoid syndrome. INTRODUCTION: isotretinoin (RA), used for the treatment of cystic acne, is a powerful teratogen, causing craniofacial dysmorphisms and neural tube defects. We present two patients with RA embryopathy and oculomotor nerve synkinesis. methods: Retrospective review of patient records. RESULTS: Two patients presented with third nerve synkinesis and fetal RA exposure. Both had marked elevation of the upper eyelids on adduction such that the lid fissures alternately opened and closed on gaze from side to side. Both patients showed typical dysmorphisms of RA embryopathy. The first patient had complete agenesis of the cerebellar vermix and died at 2 years. The second patient had restricted extraocular muscles in one eye and was exotropic and hypotropic. DISCUSSION: Both patients demonstrated simultaneous innervation of the medial rectus and levator palpebrae muscles causing coincident lid elevation in adduction. This evidence of oculomotor nerve synkinesis is consistent with animal studies showing abnormalities in the formation of cranial nerve ganglia following fetal RA exposure. CONCLUSION: RA is a powerful teratogen. These patients provide additional clinical evidence of its influence on neural migration during early development. ( info) |
5/10. Correction of congenital blepharoptosis in oculomotor-abducens synkinesis. A 4-year-old boy was referred for blepharoptosis. Examination revealed the presence of oculomotor-abducens synkinesis (right upper eyelid elevation with right gaze). Reports of congenital oculomotor-abducens synkinesis syndromes are rare. Two surgeries required more levator resection than anticipated to obtain the first, to our knowledge, reported successful result in this condition. ( info) |
6/10. Mirror movements following cortical resection of polymicrogyria in a child with intractable epilepsy. Mirror movements may be congenital or acquired. There are few reports of acquired mirror movements in pediatric patients. Further, mirror movements in children with epilepsy have rarely been reported. A 9-year old male, with intractable partial epilepsy resulting from polymicrogyria of the right hemisphere, underwent cortical resection of the right frontotemporoparietal region for a malformation of cortical development. He developed left hemiplegia and mirror movements in the left hand in the postoperative period. Four months after surgery, he remained seizure-free with mild residual left-sided hemiplegia and persistent mirror movements. Mechanisms postulated for mirror movements include aberrant pyramidal tract development and transcallosal inhibitory pathways. The latter mechanism might have contributed to the mirror movements observed in this child. This study is the first report of mirror movements following focal cortical resection for intractable epilepsy due to polymicrogyria. ( info) |
7/10. Paediatric phenotype of kallmann syndrome due to mutations of fibroblast growth factor receptor 1 (FGFR1). kallmann syndrome characterised by hypogonadotropic hypogonadism (HH) and anosmia is genetically heterogeneous with X-linked, autosomal dominant and autosomal recessive forms. The autosomal dominant form due to loss of function mutation in the fibroblast growth factor receptor 1 (FGFR1) accounts for about 10% of cases. We report here three paediatric cases of kallmann syndrome with unusual phenotype in two unrelated patients with severe ear anomalies (hypoplasia or agenesis of external ear) associated with classical features, such as cleft palate, dental agenesis, syndactylia, micropenis and cryptorchidism. We found de novo mutation in these two patients (Cys178Ser and Arg622Gly, respectively), and one inherited Arg622Gln mutation with intrafamilial variable phenotype. These genotype-phenotype correlations indicate that paediatric phenotypic expression of FGFR1 loss of function mutations is highly variable, the severity of the oro-facial malformations at birth does not predict gonadotropic function at the puberty and that de novo mutations of FGFR1 are relatively frequent. ( info) |
| Lipomas of the cerebellopontine angle (CPA) are unusual tumors that typically present with hearing loss, tinnitus, dizziness, and occasionally facial neuropathies. We describe the case of a healthy 42-year-old woman who presented with left-sided hearing loss and facial synkinesis. T1-weighted magnetic resonance imaging revealed an enhancing lesion of the left CPA with no signal on fat suppression sequences. Despite conservative therapy, the patient developed progressive hemifacial spasm, and a suboccipital craniotomy approach was used to debulk the tumor, which encased cranial nerves V, VII, VIII, IX, X, and XI. Surgical histopathology demonstrated mature adipocytes, consistent with lipoma. Two years after surgery, the patient remains free of facial nerve symptoms. cerebellopontine angle lipomas are rare lesions of the skull base and are reliably diagnosed with T1-weighted and fat suppression magnetic resonance sequences, which we recommend in the routine radiologic workup of CPA tumors. Accurate preoperative diagnosis is crucial because most CPA lipomas should be managed conservatively. Partial surgical resection is indicated only to alleviate intractable cranial neuropathies or relieve brainstem compression. ( info) |
9/10. Treatment of cremaster synkinesias with botulinum toxin A: a video case report. Synkinesias secondary to nerve lesions and aberrant re-innervation are well-known phenomena especially after lesions of the facial nerve. Synkinesias can successfully be treated with botulinum toxin A (BTx A). Synkinesias of the cremaster muscle have not been described or treated to date. We present the case of a 62-year-old man who developed synkinesias of both cremaster muscles after extensive laparatomy for esophageal cancer. Treatment of synkinesias with various oral medications had been unsuccessful. electromyography-guided injections of BTx A in both cremaster muscles (15 MU on the right and 10 on the left) led to significant symptom relief for an average of 8 weeks. We present the case including pre- and posttreatment video clips. ( info) |
| We report a case of acquired abducens-oculomotor synkinesis, internuclear ophthalmoplegia, and abducens nerve palsy following brainstem hemorrhage. Weakening surgery on the medial rectus muscle did not eliminate the synergistic movement. The mechanism responsible for the abducens-oculomotor synkinesis is discussed. ( info) |