Bruno V. Gallo

Effects of vagal nerve stimulation on laryngeal function

Functional electrical stimulation is a developing methodology that shows significant potential in the management of peripheral neuromuscular deficits. Potential applications in the head and neck area, including control of bilateral vocal fold paralysis and spasmodic dysphonia, have recently been explored. Despite promising early results, very little is known about the mechanisms of action or the long-term effects of electrical stimulation on human laryngeal function. Recent development of implantable vagal nerve stimulators as a method to control intractable seizures in individuals who have not responded to medication provides a unique opportunity to study its effect on the normal human larynx. Laryngeal and vocal function testing was studied on five individuals who had undergone vagal nerve stimulator implants for intractable seizures. Consistent abduction/adduction of the left vocal fold was achieved at 20 and 40 Hz, respectively. Higher levels of electrical stimulation produced hemispasm of the larynx. Results were consistent with studies in the literature of recurrent laryngeal nerve stimulation in animal and human models. The vagus nerve provides relatively easy access for implantation of electrodes to provide electrical stimulation to the muscles of the larynx. Vagal nerve stimulation may prove efficacious in the treatment of movement disorders of the larynx; further study is needed.

Objective monitoring of tremor and bradykinesia during DBS surgery for Parkinson disease

Objective: High-frequency subthalamic nucleus deep brain stimulation (STN-DBS) is an established treatment for patients with advanced Parkinson disease (PD). To date, intraoperative monitoring of parkinsonian symptoms, such as tremor and bradykinesia, is largely based on subjective strategies. We conducted a pilot study to evaluate short-term intraoperative outcomes of unilateral macrostimulation of the STN-DBS in PD patients using a neuromotor symptom registration device (CATSYS 2000 System). Methods: We studied 12 consecutive PD patients who received staged unilateral STN-DBS implants and 10 male control subjects free of neurologic deficits using a simple portable system with two sensors: a tremor pen and a touch recording plate. Results revealed excellent test–retest reliability for postural tremor in control subjects. PD patients were evaluated preoperatively during “off” state and intraoperatively for rest, postural tremor intensity, and frequency of finger tapping. Comparisons between premacrostimulation and postmacrostimulation were made using analysis of variance for repeated measures. Results: Electronic rest tremor registration revealed a mean improvement of ×12.5 in tremor intensity measurements in the stimulated/contralateral side (p = 0.002). An overall ×3.8 improvement was registered on the nonstimulated/ipsilateral side. Significant improvements after STN-DBS were also recorded for postural tremor and frequency of finger tapping. Conclusion: Using a noninvasive, simple, and sensitive electronic recording method of intraoperative motor symptom registration, we were able to supplement short-term clinical observation by objectively quantifying the characteristics of tremor and finger tapping in response to subthalamic nucleus deep brain macrostimulation.

HIV encephalitis presenting with severe generalized chorea

We report a case of rapidly progressive encephalopathy and generalized chorea due to HIV encephalitis.The patient was a 24-year-old man known to be HIV-seropositive for 4 years. The severity of the movement disorder resulted in rhabdomyolysis. Sepsis developed and he died after a 21-day hospitalization. Pathologic study revealed prominent neuronal loss and gliosis of subcortical regions. Acute encephalopathy with generalized chorea may be a rare consequence of HIV encephalitis. NEUROLOGY 1996;46: 1163-1165

Multi-Modal Hallucinations and Cognitive Function in Parkinson’s Disease

Background/Aims: Hallucinations have been linked to a constellation of cognitive deficits in Parkinson’s disease (PD), but it is not known whether multi-modal hallucinations are associated with greater neuropsychological dysfunction. Methods: 152 idiopathic PD patients were categorized based on the presence or absence of hallucinations and then were further subdivided into visual-only (VHonly; n = 35) or multi-modal (VHplus; n = 12) hallucination groups. All participants underwent detailed neuropsychological assessment. Results: Participants with hallucinations performed more poorly on select neuropsychological measures and exhibited more mood symptoms. There were no differences between VHonly and VHplus groups. Conclusions: PD patients with multi-modal hallucinations are not at greater risk for neuropsychological impairment than those with single-modal hallucinations.

Epilepsy, surgery, and the elderly

Treatment of elderly patients with epilepsy may present unique challenges to physicians. Co-morbid conditions and drugs to treat such conditions are common in elderly patients, possibly complicating epilepsy therapies that are dependent on drugs alone. For this reason, surgical intervention may be an attractive option for elderly patients with epilepsy, particularly for medically intractable patients with key disease features, such as lateralization and precisely localized epileptic foci. Curative procedures, including lobectomy and lesionectomy, are most likely to lead to seizure freedom, but not all patients are candidates for such procedures. When a curative surgical procedure is not an option, palliative procedures, including vagus nerve stimulation and deep brain stimulation, may be viable options. Vagus nerve stimulation has been reported to reduce seizure rates and improve quality of life in elderly patients with epilepsy. Currently, widespread therapeutic application of deep brain stimulation is limited by risks, costs, and pending studies.

Objective tremor registration during DBS surgery for Essential Tremor

Essential Tremor (ET) is characterized by a 4-12-Hz postural and kinetic tremor, most commonly affecting the upper limbs. Deep brain stimulation (DBS) of the thalamus (Vim) has been found to be highly effective in severe/refractory forms of ET. Intra-operative assessment of tremor is performed using clinical methods based on patient and physician perception of tremor intensity. We present for the first time the case of a patient whose tremor was objectively monitored/quantified pre- and intra-operatively using device-based tremor registration to supplement clinical measures. We present the case of a 76-year-old right-handed woman that received unilateral (left-sided) DBS of the ventrointermediate (Vim) nucleus of thalamus (Vim) for medically refractory ET. Tremor was monitored with an accelerometer-based Tremor Pen, which is part of a simple portable device (CATSYS 2000 System, Danish Product Development Ltd., DK, www.catsys.dk). The patient was asked to perform tasks for tremor evaluation before and during thalamic DBS. Tremor quantification revealed a significant improvement (34.7-fold) in the contralateral (right) limb following macro-stimulation. No significant improvement was registered in the ipsilateral (non-operated) side. Simple electronic tremor registration methods during DBS of the Vim nucleus of the thalamus may supplement the existing methodology that is solely based on subjective measures derived from clinical observations.

Acquired abducens-trigeminal synkinesis

Acquired synkinesis after trauma affecting the oculomotor nerve was first described by Gowers in 1879.1 Several nerve combinations have been described, including congenital trigemino-oculomotor and trigemino-abducens synkinesis.2-4 We describe a patient with an acquired synkinesis of painful involuntary jaw closure triggered by voluntary leftward gaze. Case report. A 40-year-old man presented with the complaint of frequent involuntary forceful left jaw closure with horizontal gaze to the left. A motor vehicle accident at age 18 had resulted in traumatic brain injury. After prolonged coma, his neurologic deficits included left hemiparesis, dysarthria, and left ophthalmoparesis. He gradually regained strength. Dysarthria and diplopia remained. He had several ophthalmologic procedures performed on the left eye. Botulinum toxin injections to the extraocular muscles improved fusion, but he continued to have residual diplopia. Involuntary jaw closure began 5 years after his injury but before his eye surgery. Horizontal gaze to the left triggered forceful closure of the left mandible and …

Pharmacokinetics and muscle histopathology of intramuscular valproate

To determine the safety and pharmacokinetics of parenteral sodium valproate healthy mature greyhound dogs, were given intramuscular injections following intravenous injections. Dosings intravenously and intramuscularly were at 20, 40 and 60 mg/kg in the three groups. Intravenous infusion rates were constant. Sodium valproate solution concentrations of 300, 400 and 500 mg/ml were administered. Intramuscular valproate was quickly absorbed. Bio-availability approached 70%. Half life of 120 min was calculated. Toxic muscle necrosis was observed at all concentrations. Dosing valproate intramuscularly in humans is problematic in view of the muscle damage. Despite tissue damage sodium valproate was well absorbed intramuscularly. The intravenous injection of valproate at high concentrations, large doses and fast infusion rates produced no evidence of cardiotoxicity and levels of 180 micrograms/ml.

Staged unilateral or bilateral STN-DBS?

We read with great interest the excellent study by Samii et al. reporting their results on staged unilateral versus bilateral subthalamic nucleus stimulator implantation in Parkinson disease.1 The authors report that off-medication UPDRS motor scores improved to similar degrees after each staged STN electrode implantation. Improvements in off-medication ADL scores, dyskinesia scores, complications of therapy, and medication dose reduction occurred after unilateral STN stimulation with smaller improvements after the second operation. On the basis of their findings the authors conclude that most patients with PD would benefit from bilateral STN stimulation. There is an ongoing debate on the STN-DBS implantation approach (staged unilateral vs. bilateral). Although bilateral STN electrode implantation is considered by many a “standard approach,” unilateral STN-DBS also provides improvement of motor symptoms as well as quality of life, reduces requirements for medication, and possibly enhances mental flexibility.2 Furthermore, unilateral surgical procedures can be less frequently associated with severe complications (intracranial, extracranial, and hardware related) than bilateral procedures.3,4 Another advantage of the unilateral approach is the ipsilateral effect of neurostimulation. Using objective intraoperative monitoring of rest, postural tremor, and bradykinesia using CATSYS (we studied the effects of neurostimulation of the subthalamic nucleus. During a unilateral procedure, we reported a 12.5-fold improvement in rest tremor intensity measurements in the stimulated (contralateral) side and a 3.8-fold improvement in the non-stimulated (ipsilateral side) following neurostimulation. Improvements were also registered for postural tremor in the ipsilateral side.5 Similarly, Chung et al. recently reported that at 6 months after unilateral STN DBSsurgery, the subscore of UPDRS III of body parts contralateral to the DBS implantation had improved by 48% (P 0.028), and the ipsilateral subscore of UPDRS III and the axial subscore of UPDRS III had improved by 20% (P 0.027) and 39% (P 0.028), respectively.6 Disadvantages of staged unilateral approach include higher costs and lack of rapid bilateral improvement. Considering the lower surgical risks, the proven efficacy and the demonstrated bilateral effects of unilateral subthalamic nucleus neurostimulation, we suggest that a staged approach should be considered as an alternative to simultaneous bilateral STN-DBS. Older patients and patients with marked asymmetric motor symptomatology may especially benefit from such an approach since they may never develop a need for additional electrode implantation.2 More studies on the subject are needed to determine the personalized approach to neurostimulation.

Chronic inflammatory polyradiculoneuropathy associated with alopecia universalis.

We report a patient with concurrent chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and alopecia universalis. A dramatic improvement in strength accompanied the administration of prednisone, although no regrowth of hair was noted. CIDP and alopecia universalis are two relatively rare autoimmune disorders. The simultaneous occurrence of these disorders suggests a common pathogenetic mechanism, including the possibility of shared antigens between peripheral nerve myelin and the hair follicle.