Reduced genioglossus muscle activity caused by fluid overload in anesthetized rats

INTRODUCTION

Although the precise cause of obstructive sleep apnea (OSA) remains unknown, various anatomical or structural factors are thought to influence upper airway patency. Recent clinical studies show that OSA is frequently observed among patients with fluid-retaining states, such as heart/renal failure and postsurgery. It is important to note that a cause-effect relationship is not yet established, and our understanding of the effects of fluid overload is limited. The goal of this study was to investigate an animal model that can characterize the physiological changes that occur in response to fluid overload.

METHOD

Acute nonsurvival experiments were conducted in 16 Sprague-Dawley rats. Rats were initially anesthetized by inhaled isoflurane, while the femoral vein was cannulated and urethane (1.2-1.5 g/Kg body weight) was gradually delivered intravenously to induce anesthesia. Additional doses of urethane were delivered as necessary to maintain a surgical plane of anesthesia. A surgical incision was made on the cervical area to catheterize carotid artery to measure blood pressure. A pair of stainless-steel wires was injected into the tongue to measure genioglossus muscle activity (GGEMG). All physiological measurements were recorded as intravenous infusion of saline was provided to the rat (infusion rate = 22 ml/kg over 30 min).

RESULTS

Acute saline overloading resulted in a 33% decrease in GGEMG, when compared to baseline. There was also a gradual drop in the respiratory rate (13% decrease) that reached statistical significance at 10 min after infusion was stopped. The blood pressure exhibited a 14% increase which subsequently returned to baseline within 40 min stopping infusion. There were no significant changes in the heart rate.

CONCLUSION

The results of this study indicate that systemic fluid overload can affect significant changes in different physiological systems including reduction in genioglossus muscle activity, increase in blood pressure, and change autonomic nervous system function.

Cranial nerve outcomes in regionally recurrent head & neck melanoma after sentinel lymph node biopsy

OBJECTIVE

Characterize long-term cranial nerve (CN) outcomes following sentinel lymph node biopsy (SLNB) based management for head and neck cutaneous melanoma (HNCM).

METHODS

Longitudinal review of HNCM patients undergoing SLNB from 1997-2007.

RESULTS

Three hundred fifty-six patients were identified, with mean age 53.5 ± 19.0 years, mean Breslow depth 2.52 ± 1.87 mm, and 4.9 years median follow-up. One hundred five (29.4%) patients had SLNB mapping to the parotid basin. Eighteen patients had positive parotid SLNs and underwent immediate parotidectomy / immediate completion lymph node dissection (iCLND), with six possessing positive parotid non-sentinel lymph nodes (NSLNs). Fifty-two of 356 (14.6%) patients developed delayed regional recurrences, including 20 total intraparotid recurrences: five following false negative (FN) parotid SLNB, three following prior immediate superficial parotidectomy, two following iCLND without parotidectomy, and the remaining 12 parotid recurrences had negative extraparotid SLNBs. Parotid recurrences were multiple (4.9 mean recurrent nodes) and advanced (n = 4 extracapsular extension), and all required salvage dissection including parotidectomy. Immediate parotidectomy/iCLND led to no permanent CN injuries. Delayed regional HNCM macrometastasis precipitated 16 total permanent CN injuries in 13 patients: 10 CN VII, five CN XI, and one CN XII deficits. Fifty percent (n = 10) of parotid recurrences caused ≥1 permanent CN deficits.

CONCLUSIONS

Regional HNCM macrometastases and salvage dissection confer marked CN injury risk, whereas early surgical intervention via SLNB ± iCLND ± immediate parotidectomy yielded no CN injuries. Further, superficial parotidectomy performed in parotid-mapping HNCM does not obviate delayed intraparotid recurrences, which increase risk of CN VII injury. Despite lack of a published disease-specific survival advantage in melanoma, early disease control in cervical and parotid basins is paramount to minimize CN complications.

LEVEL OF EVIDENCE

4 (retrospective case series) Laryngoscope, 130:1707-1714, 2020.

Electrical stimulation of cranial nerves in cognition and disease

The cranial nerves are the pathways through which environmental information (sensation) is directly communicated to the brain, leading to perception, and giving rise to higher cognition. Because cranial nerves determine and modulate brain function, invasive and non-invasive cranial nerve electrical stimulation methods have applications in the clinical, behavioral, and cognitive domains. Among other neuromodulation approaches such as peripheral, transcranial and deep brain stimulation, cranial nerve stimulation is unique in allowing axon pathway-specific engagement of brain circuits, including thalamo-cortical networks. In this review we amalgamate relevant knowledge of 1) cranial nerve anatomy and biophysics; 2) evidence of the modulatory effects of cranial nerves on cognition; 3) clinical and behavioral outcomes of cranial nerve stimulation; and 4) biomarkers of nerve target engagement including physiology, electroencephalography, neuroimaging, and behavioral metrics. Existing non-invasive stimulation methods cannot feasibly activate the axons of only individual cranial nerves. Even with invasive stimulation methods, selective targeting of one nerve fiber type requires nuance since each nerve is composed of functionally distinct axon-types that differentially branch and can anastomose onto other nerves. None-the-less, precisely controlling stimulation parameters can aid in affecting distinct sets of axons, thus supporting specific actions on cognition and behavior. To this end, a rubric for reproducible dose-response stimulation parameters is defined here. Given that afferent cranial nerve axons project directly to the brain, targeting structures (e.g. thalamus, cortex) that are critical nodes in higher order brain networks, potent effects on cognition are plausible. We propose an intervention design framework based on driving cranial nerve pathways in targeted brain circuits, which are in turn linked to specific higher cognitive processes. State-of-the-art current flow models that are used to explain and design cranial-nerve-activating stimulation technology require multi-scale detail that includes: gross anatomy; skull foramina and superficial tissue layers; and precise nerve morphology. Detailed simulations also predict that some non-invasive electrical or magnetic stimulation approaches that do not intend to modulate cranial nerves per se, such as transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS), may also modulate activity of specific cranial nerves. Much prior cranial nerve stimulation work was conceptually limited to the production of sensory perception, with individual titration of intensity based on the level of perception and tolerability. However, disregarding sensory emulation allows consideration of temporal stimulation patterns (axon recruitment) that modulate the tone of cortical networks independent of sensory cortices, without necessarily titrating perception. For example, leveraging the role of the thalamus as a gatekeeper for information to the cerebral cortex, preventing or enhancing the passage of specific information depending on the behavioral state. We show that properly parameterized computational models at multiple scales are needed to rationally optimize neuromodulation that target sets of cranial nerves, determining which and how specific brain circuitries are modulated, which can in turn influence cognition in a designed manner.

Observations on the Natural History of Camurati-Engelmann Disease

Camurati-Engelmann disease (OMIM 31300) is a rare cranio-tubular bone dysplasia characterized by osteosclerosis of the long bones and skull caused by dominantly-inherited mutations in the transforming growth factor beta 1 (TGFB1) gene. A wide variation in phenotype has been recognized, even within families carrying the same mutation. In addition, aspects of the natural history of the disorder, in particular whether it is always progressive or can remit spontaneously, remain uncertain. In a large kindred carrying a TGFB1 gene mutation (c.653G > A; p.R218H) we have attempted to clarify the extent of phenotypic variability and the natural history of the disease through detailed individual histories of symptoms, and skeletal imaging by both radiography and scintigraphy. Only one subject had the classical childhood onset with bone pain in the legs and gait disturbance. Eight subjects reported the onset of leg pain in their teenage years that, by their early 20s, had either resolved or persisted at a low level. Two of these eight later developed cranial nerve palsies. There was a wide variation in the radiographic appearance in adults, but disease extent and activity in long bones, as assessed by scintigraphy, was inversely correlated with age (p < 0.025). In younger subjects the radiographic and scintigraphic appearances were concordant, but in older subjects the scintigram could be quiescent despite florid radiographic changes. Sequential scintigrams in two subjects showed reduced activity in the later scan. One subject had suffered meningoencephalitis in early childhood that resulted in paresis of one arm. The affected arm showed markedly less disease involvement, implicating mechanical or growth factors in its etiology. Our data suggest that the natural history of Camurati-Engelmann disease can be benign, and that disease activity commonly attenuates in adulthood. Severe cases of childhood onset and/or with cranial nerve involvement, may occur only in a minority of mutation carriers. © 2019 American Society for Bone and Mineral Research.

Brainstem Glioma: Clinical Profile and Challenges of Management in a Developing Country

BACKGROUND AND OBJECTIVES

Brainstem gliomas are relatively rare tumours of the central nervous system which have varying presentations and clinical course. This study aims to analyse the clinical profile and challenges of management of these tumours in a resource-limited country.

METHIODS

We retrospectively analysed the data from the records of the patients managed for briainstem glioma between January 2010 and July 2017.

RESULTS

There were 11 patients in the study (7 males and 4 females). The median age at diagnosis was 9 years. Eight of the patients were less than 15 years. The duration of symptoms ranged from 1 month to 2 years. All the patients had cranial nerve deficits at presentation, while 7 patients had cerebellar signs. Hydrocephalus was present in 4 patients. The lesion was pontine in 9 patients and tectal in 2. Three of the patients with hydrocephalus had ventriculoperitoneal shunt insertion while one patient refused surgery. Only one of the patients had radiotherapy. None of the patients received chemotherapy. A patient was dishcarged against medical advice. One patient is still alive after 4 years while another patient is alive after 2 years. The other 9 patients are dead with a mean survival period of 6 months.

CONCCLUSION

Most of the tumours in this series were located in the pons and ran aggressive courses. Majority of our patients did not have access to radiotherapy while none had chemotherapy.

Novel method of intraoperative ocular movement monitoring using a piezoelectric device: experimental study of ocular motor nerve activating piezoelectric potentials (OMNAPP) and clinical application for skull base surgeries

Intraoperative monitoring systems that utilize various evoked potentials for the detection and/or preservation of cranial nerves have become increasingly common due to recent technical and commercial developments, particularly during skull base surgeries. We established a novel system for the intraoperative monitoring of the extraocular motor nerves (eOMNs) using a piezoelectric device capable of detecting imperceptible vibrations induced by ocular movement, with sensors placed on the eyelids alone. We first evaluated the efficacy and reliability of this device for the intraoperative monitoring of eOMNs in two Beagle dogs. Based on the results, we then determined the appropriate stimulation parameters for use in human surgical cases involving removal of various skull base tumors. Animal experiments revealed that a 0.4 mA monopolar electrical stimulation was required to elicit significant responses and that these responses were not inferior to those obtained via the electrooculogram/electromyogram. Significant responses were also detected in preliminary clinical investigations in human patients, following both direct and indirect monopolar electrical stimulation of the oculomotor and abducens nerves, although obtaining responses from the trochlear nerve was difficult. Intraoperative monitoring using a piezoelectric device provides a simple and reliable method for detecting eOMNs, especially the oculomotor and abducens nerves. This monitoring system can be adapted to various surgeries for skull base tumor.

Venomous snakebites in children in southern Croatia

This retrospective study represents observation of 160 children and adolescents aged up to 18 years that experienced venomous snakebites in southern Croatia and were treated in the Clinical Department of Infectious Diseases in the University Hospital Centre Split from 1979 to 2013. The main purpose of this research was to determine the epidemiological characteristics, clinical presentation, local and general complications, and received treatment. Most bites occurred during warm months, from early May to late August (80%), mostly in May and June. Upper limb bites were more frequent (59%) than lower limb bites (40%). Out of the total number of poisoned children, 24% developed local, and 25% general complications. The most common local complications were haemorrhagic blisters that occurred in 20% children, followed by compartment syndrome presented in 7.5% patients. The most dominated general complication was cranial nerve paresis or paralysis, which was identified in 11.2% patients, whereas shock symptoms were registrated in 7% children. According to severity of poisoning, 9.4% children had minor, 35% mild, 30.6% moderate, and 24.4% had severe clinical manifestation of envenomation. Only one (0.6%) child passed away because of snakebite directly on the neck. All patients received antivenom produced by the Institute of Immunology in Zagreb, tetanus prophylaxis as well, and almost all of them received antibiotics, and a great majority of them also received corticosteroids and antihistamines. Neighter anaphylactic reaction nor serum disease were noticed in our patients after administrating antivenom. A total of 26% children underwent surgical interventions, and incision of haemorrhagic blister was the most common applied surgical treatment, which was preformed in 15.6% patients, while fasciotomy was done in 7.5% subjects. All of our surgically treated patients recovered successfully.

[Multisession cyberknife radiosurgery for cavernous sinus hemangiomas: medium- and long-term outcomes]

OBJECTIVE

To investigate the medium- and long-term outcomes of multisession cyberknife radiosurgery intreating cavernous sinus hemangiomas (CSH).

METHODS

Between January 2008 and February 2012, 45 patients with CSH, including 35 female and 10 male patients with a mean age of 53 years (range: 26-80 years), underwent multisession cyberknife radiosurgery. The mean diameter of the CSH was 47.0 mm (range: 23.0-75.0 mm). The tumor volume ranged from 2.9 to 140.1 cm³, with a mean of 40.1 cm³. Eleven giant CSH with tumor volume ≥ 40.0 cm³ were irradiated by cyberknife in 4 fractions, 28 large tumors with tumor volume 10.0-40.0 cm³ in 3 fractions, 4 tumors with tumor volume 5.0-10.0 cm³ in 2 fractions, 2 small tumors with tumor volume ≤ 5.0 cm³ in 1 fraction. After the treatment, all patients had regular clinical and radiological follow-up at 6-month intervals. A combination of the neurologic examination and MRI information was used to evaluate the overall response.

RESULTS

All patients were followed up for 22-70 months with a mean of 37.7 months. One patient died of stroke 3 years post cyberknife, but the follow-up MRI showed that the CSH shrank in volume. Eight patients with giant CSH had slight headache after finishing cyberknife radiosurgery, and relieved with mannitol and dexamethasone treatment. Neurological deficits in patients had improved or disappeared at 6 to 12 months post cyberknife. None of these patients showed any deterioration in symptoms or new cranial nerve deficits during the follow-up. Latest follow-up imaging demonstrated that tumors decrease > 80% in 15 patients, > 60% to 80% in 18 patients (including the death patient), 40%-60% in 12 patients post cyberknife. Two patients reported occurrence of seizures and maintaining seizure control after antiepileptic drugs administration.

CONCLUSIONS

Multisession cyberknife radiosurgery is confirmed to provide medium and long-term local tumor control and symptom improvement. It is a safe and effective treatment modality for CSH, and may serve as a promising treatment option in the future.

[Management of jugular foramen Schwannomas]

OBJECTIVE

To discuss surgical approach selection and treatment strategy for preservation of the facial and lower cranial nerves' function in jugular foramen schwannomas surgery.

METHODS

Retrospectively analyzed the clinical presentation, surgical approaches selection, facial and lower cranial nerves follow-up outcomes of 38 jugular foramen Schwannomas, who received operations in the Department of Otolaryngology Head and Neck Surgery, Xinhua Hospital affiliated to Shanghai Jiaotong University, School of Medicine during 2002 and 2012.

RESULTS

A total of 38 patients, including 18 men and 20 women, with ages ranged from 21 to 70 years (mean 45.3). Headache or neck pain in preoperative clinical presentation was present in 27 patients (71.1%) and cervical mass in 9 patients (23.7%). Cranial nerve impairments, mainly the vagus nerve, were present in 21 patients (55.3%). MRI finding: 19 tumors were intra- and extracranial, 10 were intracranial and 9 were extracranial. According to the tumor location and region, select the surgical approaches. 25 patients used infratemporal fossa type A approach, 5 patients used petrous occipital transsigmoid approach and 8 patients used transcervial approach to remove tumors. The percentage of total resection was 92.1% (35/38). Adjunctive radiosurgery was used in the management of residual tumor in two patients. All cases obtained ultimately tumor control. Patients were followed by MRI every 6 months for 1 year. Thereafter, they performed follow-up imaging every 1-2 years, and the cranial nerve function was analyzed and evaluated. They were followed up from 26-124 months (median follow-up was 62.3 months). During follow-up period, good facial function was obtained in 36 patients (94.7%). All patients had no swallowing disorder. Complete compensation of lower cranial nerve function was achieved in all patients.

CONCLUSIONS

The preoperative estimation and location of tumor in nature is of great importance in the determination of proper surgical planning of jugular foramen Schwannomas. Facial nerve and lower cranial nerve function can be preserved in maximal degree by proper surgical approaches and careful operative manipulation. Initial surgical resection followed by radiosurgery may be an effective option for some special patients.

Cranial Nerve Dysfunction Associated with Cavernous Dural Arteriovenous Fistulas After Transvenous Embolization with Onyx

PURPOSE

Cranial nerve dysfunction (CND) is not uncommon in patients with cavernous dural arteriovenous fistulas (cDAVFs), and may represent an initial manifestation or a complication after endovascular treatment. This study evaluated the outcome of CND associated with cDAVFs after transvenous embolization (TVE) using Onyx.

MATERIALS AND METHODS

Forty-one patients with cDAVFs were treated with TVE in our department between April 2009 and October 2013. For each patient, clinical and radiologic records were retrospectively reviewed and evaluated, with an emphasis placed on evaluating the outcomes of the pre-existing cDAVF-induced CND and the TVE-induced CND.

RESULTS

Of the 41 cases, 25 had a history of preoperative CND. Postoperatively, gradual remission to complete recovery (CR) within 8 months was observed in 17 of these cases, transient aggravation in 7, and significant improvement to be better than preoperative function but no CR in 1. All aggravation of CND occurred immediately or within 1 day after TVE and resolved completely within 5 months. Nine patients developed new CND after TVE. New CND occurred during the perioperative period in 8 cases, but all cases resolved completely within 15 days-6 months. Delayed CND was observed in 3 cases with a time lag of 3-25 months after TVE. Two of these completely resolved within 20 days-1 month and the remaining case significantly improved.

CONCLUSION

Both the pre-existing cDAVF-induced CND and the TVE-induced new or aggravated CND completely resolved in almost all cases after embolization with Onyx.

[Intraoperativ electrophysiological monitoring during neurosurgery on eloquent structures]

OBJECTIVE

We summarize our experiences on intraoperative electrophysiological monitoring during neurosurgical procedures on eloquent neuronal structures.

PATIENTS, METHODS

Sixty patients were enrolled retrospectively in our study with pathologies involving eloquent neuronal structures. They were operated between May 2011. and March 2012. at the University of Debrecen, Department of Neurosurgery and at the National Institute of Neurosciences. Patients underwent standard preoperative examinations due to the primary pathology. In all cases we used intraoperative electrophysiological monitoring. We had 22 cases with cranial nerve monitoring, 10 cases with cauda monitoring, 16 cases with motor system monitoring, six cases with complex spinal cord monitoring, three degenerative spine reconstructions and 3 awake surgeries.

RESULTS

We found that with the use of intraoperative electrophysiology we could make these neurosurgical procedures safer, and were able to optimize the extent of resection in the cases of oncological pathologies.

CONCLUSIONS

Our experiences as well as the international literature suggests that in certain high risk neurosurgical procedures intraoperative electrophysiology is indispensible for safe and optimally extended operation.

Occipital nerve stimulation for chronic migraine

Occipital nerve stimulation may be effective in treating chronic migraine. Six studies, including three double-blind studies, were performed, with five showing evidence of benefit. However, of the three randomized, controlled trials, none has met a primary endpoint successfully. A separate study suggested a benefit for combined supraorbital and greater occipital nerve stimulation.

Clinical profile of Guillain Barre syndrome

OBJECTIVES

To study clinical presentation, hospital care and outcome of patients of Guillain Barre Syndrome (GBS) and number of patients of respiratory failure and need for ventilators. To study efficacy of IVIg in patients of GBS.

MATERIAL AND METHODS

40 patients of GBS studied in detail including history, clinical examination and investigations (Nerve conduction velocity and C.S.F. examination). All patients were watched for respiratory insufficiency and those who developed respiratory paralysis were given assisted mechanical ventilation. Patients were treated with IVIG and outcome was observed. Outcome of 2 groups of patients one treated with IVIg and other not treated with IVIg (supportive line of treatment) were compared.

RESULTS

Commonest age group affected was 13-40 yrs. The male:female ratio was 1.5:1. Antecedent infection in form of fever, cough [11 patients], loose motions [10 patients] were present in 21 out of 40 patients. Quadriparesis was present in 39 patients and paraparesis in 1 patient. Cranial nerve involvement was seen in 25 out of 40 patients. Facial nerve was involved in 12 [30%] patients and Glossopharyengeal, vagus nerves were involved in 12 [30%] patients. Areflexia was found in all 40 patients. In CSF examination, albuminocytologic dissociation was present in 17 out of 26 patients. NCV findings show conduction velocity slowing, delayed f latencies in 90% patients. Out of 40 patients, 13 [30%] required mechanical ventilation. Out of 40 patients, 14 were treated with IVIg, 4 patients treated with plasmapheresis and 22 patients received only supportive treatment. Out of 40 patients 30 [75%] patients recovered completely, 8 [20%] patients died and 2 [5%] patients developed severe neurologic deficit.

CONCLUSION

GBS is more common in 13-40 yrs age group with male:female ratio of 1.5:1. Antecedent infection is seen in 55% patients. Commonest presentation was paresthesia in legs and ascending paralysis. One third [32.5%] patients developed respiratory paralysis and needed ventilatory support. Patients who received IVIg early in the course of disease had faster recovery as compared to patients who received only supportive line of treatment.

[Prospective study of the clinical features of cluster headache]

INTRODUCTION

Although cluster headache (CH) is one of the most severe human pain syndromes, its symptoms and therapeutic possibilities may be suboptimally recognised in current medical practice in Hungary.

AIM

To present the clinical characteristics of CH based on a prospective study of patients attending the Headache Service of the Department of Neurology, Semmelweis University.

METHODS

We collected information about the symptoms, diagnosis and previous treatment of CH patients by filling in a 108-item questionnaire during outpatient visits.

RESULTS

In the 5-year period between 2004 and 2008 we obtained data from 78 CH patients (57 males and 21 females; mean age: 44.6 +/- 14.6 years). The male:female ratio did not change in subgroups based on disease onset (calendar years). Ninety-three percent considered CH the most severe pain state of their life. The pain was strictly unilateral, affecting the territory of the 1st trigeminal division in all patients. The attacks were accompanied by signs of ipsilateral cranial parasympathetic activation (lactimation 83%, conjunctival injection 67%, rhinorrhea 56%, nasal congestion 43%); less frequently, signs of sympathetic dysfunction (ptosis 48%, miosis 7%) were also present. Two patients had attacks showing the typical localisation, severity and time course of CH attacks, but not accompanied by autonomic phenomena. A considerable part of the patients also observed symptoms that are usually ascribed to migraine (nausea 41%, vomiting 18%, photophobia 68%, phonophobia 58%). This may have been instrumental in the fact that, regardless of the characteristic clinical symptoms, the diagnosis of CH took 10 years on average. At the time of their examination 63% of patients were not using adequate abortive medications and 59% did not have an adequate prophylactic measure.

DISCUSSION

Cluster headache is characterised by attacks of devastating pain that warrant an early diagnosis and adequate treatment. Our study underlines that information about the diagnosis and therapy of CH should be emphasized on occasions of neurology specialty training and continuing medical education.

Cranial nerve vascular compression syndromes of the trigeminal, facial and vago-glossopharyngeal nerves: comparative anatomical study of the central myelin portion and transitional zone; correlations with incidences of corresponding hyperactive dysfunctional syndromes

OBJECTIVE

The aim of this study was to evaluate the anatomy of the central myelin portion and the central myelin-peripheral myelin transitional zone of the trigeminal, facial, glossopharyngeal and vagus nerves from fresh cadavers. The aim was also to investigate the relationship between the length and volume of the central myelin portion of these nerves with the incidences of the corresponding cranial dysfunctional syndromes caused by their compression to provide some more insights for a better understanding of mechanisms.

METHODS

The trigeminal, facial, glossopharyngeal and vagus nerves from six fresh cadavers were examined. The length of these nerves from the brainstem to the foramen that they exit were measured. Longitudinal sections were stained and photographed to make measurements. The diameters of the nerves where they exit/enter from/to brainstem, the diameters where the transitional zone begins, the distances to the most distal part of transitional zone from brainstem and depths of the transitional zones were measured. Most importantly, the volume of the central myelin portion of the nerves was calculated. Correlation between length and volume of the central myelin portion of these nerves and the incidences of the corresponding hyperactive dysfunctional syndromes as reported in the literature were studied.

RESULTS

The distance of the most distal part of the transitional zone from the brainstem was 4.19  ±  0.81 mm for the trigeminal nerve, 2.86  ±  1.19 mm for the facial nerve, 1.51  ±  0.39 mm for the glossopharyngeal nerve, and 1.63  ±  1.15 mm for the vagus nerve. The volume of central myelin portion was 24.54  ±  9.82 mm(3) in trigeminal nerve; 4.43  ±  2.55 mm(3) in facial nerve; 1.55  ±  1.08 mm(3) in glossopharyngeal nerve; 2.56  ±  1.32 mm(3) in vagus nerve. Correlations (p  < 0.001) have been found between the length or volume of central myelin portions of the trigeminal, facial, glossopharyngeal and vagus nerves and incidences of the corresponding diseases.

CONCLUSION

At present it is rather well-established that primary trigeminal neuralgia, hemifacial spasm and vago-glossopharyngeal neuralgia have as one of the main causes a vascular compression. The strong correlations found between the lengths and volumes of the central myelin portions of the nerves and the incidences of the corresponding diseases is a plea for the role played by this anatomical region in the mechanism of these diseases.

Effects of maturation and acidosis on the chaos-like complexity of the neural respiratory output in the isolated brainstem of the tadpole, Rana esculenta

Human ventilation at rest exhibits mathematical chaos-like complexity that can be described as long-term unpredictability mediated (in whole or in part) by some low-dimensional nonlinear deterministic process. Although various physiological and pathological situations can affect respiratory complexity, the underlying mechanisms remain incompletely elucidated. If such chaos-like complexity is an intrinsic property of central respiratory generators, it should appear or increase when these structures mature or are stimulated. To test this hypothesis, we employed the isolated tadpole brainstem model [Rana (Pelophylax) esculenta] and recorded the neural respiratory output (buccal and lung rhythms) of pre- (n = 8) and postmetamorphic tadpoles (n = 8), at physiologic (7.8) and acidic pH (7.4). We analyzed the root mean square of the cranial nerve V or VII neurograms. Development and acidosis had no effect on buccal period. Lung frequency increased with development (P < 0.0001). It also increased with acidosis, but in postmetamorphic tadpoles only (P < 0.05). The noise-titration technique evidenced low-dimensional nonlinearities in all the postmetamorphic brainstems, at both pH. Chaos-like complexity, assessed through the noise limit, increased from pH 7.8 to pH 7.4 (P < 0.01). In contrast, linear models best fitted the ventilatory rhythm in all but one of the premetamorphic preparations at pH 7.8 (P < 0.005 vs. postmetamorphic) and in four at pH 7.4 (not significant vs. postmetamorphic). Therefore, in a lower vertebrate model, the brainstem respiratory central rhythm generator accounts for ventilatory chaos-like complexity, especially in the postmetamorphic stage and at low pH. According to the ventilatory generators homology theory, this may also be the case in mammals.

[Damage to craniocerebral nerves in reconstructive surgery of carotid arteries]

Reconstructive operations on aortic arch branches appear to be the most efficient method of preventing acute and chronic impairments of cerebral circulation. Iatrogenic lesions of the craniocerebral nerves deteriorate the course of the immediate, and especially the remote postoperative period, decreasing quality of life and social status of the patients after endured carotid reconstructions. The authors analysed herein the outcomes in a total of 562 patients after endured carotid artery surgery for atherosclerosis or pathological tortuosity. The authors examined the incidence rate, patterns and risk factor of damage to the craniocerebral nerves in all the patients. Comprehensive prevention of damage to the craniocerebral nerves was carried out in a total of 412 patients from the Study Group and was aimed at excluding or decreasing intensity of the eff ect of the eliminable risk factors. The proposed measures made it possible to decrease the rate of lesions of craniocerebral nerves from 18.7 to 6.9% and to substantially improve the postoperative patients' quality of life.

Tinnitus in postherpetic neuralgia

We describe a woman who developed postherpetic neuralgia (PHN) located on the skin areas of the left ophthalmic division of the fifth cranial nerve without ocular involvement. PHN was associated with tinnitus, which was located ipsilaterally to the painful side and increased in proportion to the intensity of pain. Tinnitus was responsive to treatment with duloxetine, 60 mg daily, and subsided when the PHN resolved. This is the first description of tinnitus in PHN.

Primary sellar lymphoma: intravascular large B-cell lymphoma diagnosed as a double cancer and improved with chemotherapy, and literature review of primary parasellar lymphoma

Lymphoma is one of the causative factors of hypothalamus-pituitary dysfunction, and intravascular large B-cell lymphoma (IVLBCL) is a subtype of primary extranodal neoplasm. A 69-year-old woman visited our hospital because of general fatigue. We diagnosed her with presumable non-functional primary pituitary adenoma and subsequent dysfunction. Eight months after, the patient revisited our hospital because of dyspnea. Though we conducted systemic investigations including chest and abdomen enhanced computer tomography, transbronchial lung biopsy, and bone marrow biopsy, the diagnosis was not confirmed. Inadvertently, a breast cancer was found, and the surgical specimen proved that the patient had double cancer-adenocarcinoma and IVLBCL. Rituximab, cyclophosphamide, adriamycin, vincristine, and prednisolone regimen was initiated, and complete remission was achieved. Notably, the sellar mass returned to normal size with improved function. We reviewed 32 patients with primary parasellar lymphoma. In affected sites, both sellar and pituitary stalk (6.7%), both hypothalamus and pituitary stalk (6.7%), only sellar (63.3%), only pituitary stalk (6.7%), only hypothalamus (13.3%), and only clivus (3.3%) were observed. In hypothalamus-pituitary dysfunction, both anterior and posterior dysfunction (20.7%), only anterior dysfunction (58.6%), only posterior dysfunction (3.4%), and no dysfunction (17.2%) were observed. It seemed that hypothalamic lesion is related to both anterior and posterior dysfunction, while sellar lesion is related to mainly anterior dysfunction. In cranial nerve dysfunction, 2nd nerve dysfunction (45.2%) and 6th nerve dysfunction (35.5%) were frequently observed. It seemed that sellar lesion is related to both 2nd and 6th nerve dysfunction, while hypothalamic lesion is related to mainly 2nd nerve dysfunction.

Diagnostic nerve ultrasound in Charcot-Marie-Tooth disease type 1B

Ultrasound is emerging as a useful tool for evaluation of neuromuscular conditions, because it can provide high-resolution anatomic information to complement electrodiagnostic data. There have been few studies in which ultrasound was used to assess the peripheral nerves of individuals with Charcot-Marie-Tooth (CMT) disease and none involving CMT type 1B. In this study we compared nerve cross-sectional area in individuals from a single large family with CMT 1B with normal, healthy controls. We also assessed for cranial nerve enlargement in those with CMT 1B with cranial neuropathies compared to those with CMT 1B without cranial neuropathies. Individuals with CMT 1B have significantly larger median and vagus nerves than healthy controls, but no difference was seen in cranial nerve size between those with versus those without cranial neuropathies. This is the first study to characterize the ultrasonographic findings in the peripheral nerves of individuals with CMT 1B.

Neurovascular compression in painful tic convulsif

This article describes the case of a 67-year-old woman who presented with a typical left hemifacial spasm of 8-month duration. After 2 months, she experienced lacinating and sharp shock-like pain in the left side of her face affecting the V1 and V2 territories and a discrete attenuation of nauseous reflex on the left side. CT angiography and MRI revealed significant compression of left cranial nerves V, VII, VIII, IX and X by a giant and tortuous vertebro-basilar arterial complex. This case illustrates the nonlinearity of the relationship between the presence of the stressor factor and the actual manifestation of the disease.

Behavioural and electrophysiological analysis of strabismus in cats: modern context

We studied the effects of paralytic strabismus on visual behaviour and binocularity of cortical visual mechanisms by immobilization of one eye in adult cats. Visual discrimination abilities of the immobilized eye were significantly diminished despite extensive training with one or both eyes. The deficits are not caused by the immobilization itself but appear to reflect an adaptive mechanism to deal with double vision. The deficits with the immobilized eye persisted even after section of the optic chiasm, which effectively removes the direct cortical competition of the two eyes. Single-cell electrophysiological recordings showed that cortical cellular responses are modified by the immobilization, with loss of binocularity in some cells and shifting of receptive fields of other cells that continued to respond to both eyes.

[Intraoperative cranial nerves monitoring under partial neuromuscular relaxation during cerebellopontine angle tumor resection]

OBJECTIVE

To evaluate the efficacy of multiple cranial nerves monitoring under partial Seventy elective neuromuscular relaxation during cerebellopontine angle (CPA) tumor resection.

METHODS

patients undergoing CPA tumor resection via microneurosurgery were randomly allocated to 2 equal groups: Group FN receiving intraoperative facial nerve (NF) monitoring and Group MN receiving monitoring of multiple nerves: trigeminal nerve, glossopharyngeal nerve, accessory nerve or hypoglossal nerve other than the FN which were considered at risk by the neurosurgeon preoperatively. The manipulation procedure were modified according to cranial nerves monitoring and neuromuscular relaxation was maintained at train of four stimulation (TOF)=3 by continuous vencronium infusion during the acoustic neuroma resection. The function of the cranial nerves monitored were evaluated preoperatively and 8 days postoperatively.

RESULTS

Discernable and legible images of electromyographic wave complex were obtained during cranial nerve mapping and monitoring under intraoperative partial neuromuscular relaxation form all the patients. The facial nerve function of 4 patients exacerbated (from H-B grade I-II to grade III-IV) in both groups, and one new glossopharyngeal nerve function deficiency was found in Group FN, and one new hypoglossal nerve function deficiency was found in Group MN postoperatively.

CONCLUSION

Intraoperative cranial nerves monitoring under partial neuromuscular relaxation is feasible. Multiple cranial nerves combined with facial nerve monitoring seems unable to increase the short-term protective effects of nerve function after CPA tumor resection.

Combined subtemporal and retrosigmoid keyhole approach for extensive petroclival meningioma surgery: report of experience with 7 cases

OBJECTIVE

Resection of petroclival meningiomas offers great challenges to the neurosurgeons. Our experience of 7 cases using a combined subtemporal and retrosigmoid keyhole approach surgery was evaluated for the treatment of extensive petroclival meningiomas.

METHODS

From July 2002 to July 2005, resections of 7 petroclival meningiomas, which involved both supra- and infratentorial regions, were performed via a combined subtemporal and retrosigmoid keyhole approach. The extent of tumor resection was evaluated by MRI 3 months after surgery, and postoperative complications were investigated.

RESULTS

The maximum diameter of the tumors ranged from 3.4 to 6.0 cm (mean: 4.4 cm). Gross total resection (GTR) was achieved in 3 cases, giving a GTR rate of 43%. Subtotal resection (STR) was carried out in 4 cases. Neurological status remained intact in one case, while others presented with cranial nerve deficits (VII, VI, V, III and lower CN). No death was reported in the cases during the postoperative period.

CONCLUSION

The combined keyhole approach is suitable for the treatment of extensive petroclival meningiomas. It provides easy and quick access to the supra- and infratentorial juxtaclival region without any petrous bone drilling. Complications related to the approach can be minimized.

Cephalic tetanus with left infranuclear facial palsy

We report a case of 11 years old male who developed trismus associated with left infranuclear facial palsy following injury over forehead. Cephalic tetanus was diagnosed. Rarity of the case as well as mild course it ran, though the incubation period was less than seven days, is the reason for this case report.

[Pain associated with craniofacial and cervical herpes zoster]

Ophthalmological and cervical involvement of herpes zoster virus ranks second and third, respectively, in terms of localization frequency. Involvement of the cranial nerves is a particular sign of complications, notably ocular complications, possibly compromising the visual or facial prognosis through involvement of the VIIth nerve, which is responsible for facial paralysis. These types of involvement should be rapidly diagnosed and treated so as to limit these complications. The pain associated with herpes zoster remains frequent and difficult to treat, even if today the criteria for defining postzoster pain is increasingly refined. Antalgic and antiviral treatment should be initiated early, from the very first signs, to attempt to reduce the incidence of this postzoster pain. The risk factors, associated with the development of postzoster pain are age over 50 years, the severity of the skin rash and the intensity of the acute pain, and the existence of a prodromic pain phase before onset. The European Federation of Neurological Societies has recently published guidelines on the pharmacological treatments for postzoster pain. Nerve block treatments remain at a limited evidence level. Patients with postzoster pain should be managed by teams specializing in pain management as soon as conventional treatments fail.

B-cell neurolymphomatosis confined to the peripheral nervous system

Patients with neurolymphomatosis show lymphoma cells within the peripheral nerves, nerve root/plexus, or cranial nerves. However, most neurolymphomatosis patients show lymphomatous infiltration not only in the peripheral nervous system (PNS), but also in the meninges, Virchow-Robin space, and brain parenchyma. Here, we report a 74-year-old woman with diffuse large B-cell lymphoma presenting with motor-sensory-autonomic polyneuropathy and multiple cranial neuropathies. A diagnosis of neurolymphomatosis was made by sural nerve biopsy. Postmortem examination indicated that lymphoma cell infiltration in the nervous system was confined to the PNS with no involvement of the central nervous system, including the meninges. This was a very rare case of B-cell neurolymphomatosis with lymphomatous infiltration confined to the PNS, suggesting specific affinity of the lymphoma cells for the PNS in this patient.

Orbital syndromes

The orbit is a complex anatomical structure with unique properties not observed in other regions of the body. Composed of seven bones, the orbit is filled by the eye, optic nerve, lacrimal gland, extraocular muscles, peripheral motor and sensory nerves, fat, arteries, and veins. All these structures are intimately related to one another within an intricate framework of connective tissue. A variety of traumatic, vascular, inflammatory, infectious, and neoplastic processes can affect the orbit and its structures. Aside from the many primary orbital diseases, systemic disorders and pathological processes from neighboring structures (eye, ocular adnexa, oral cavity, paranasal sinuses, and intracranial cavity) can involve the orbit. A careful history and complete physical examination, with special attention to the orbit and ocular adnexa, are required to identify subtle orbital abnormalities that otherwise could be overlooked or mistakenly contributed to a nonorbital process. This article reviews the pertinent orbital anatomy, discusses the clinical evaluation and manifestations of orbital syndromes, and highlights several important orbital syndromes germane to the neurologist, including thyroid-associated orbitopathy, nonspecific orbital inflammation (also known as inflammatory orbital pseudotumor), perineural orbital invasion of cutaneous squamous cell carcinoma, rhino-orbital-cerebral mucormycosis, and carotid-cavernous sinus fistula.

Management strategies for bilateral vestibular schwannomas

BACKGROUND

Bilateral vestibular schwannomas (VS) are rare. Most patients in India present late in the course of illness with large tumors and disabling deafness. Clinical presentation and management goals are different from that of unilateral VS.

AIMS

To highlight the differences in clinical presentations and surgical results of bilateral VS compared to unilateral VS; and, to propose a management strategy for these tumors with reference to tumor size, extent of growth and the presence or absence of hearing impairment.

METHOD

This is a retrospective study of 16 patients with bilateral VS treated over 10 years in a tertiary referral hospital. Assessment of VIIth and VIIIth cranial nerve function, tumor size, volume and extent of growth was performed in all patients. The management strategy was based on Samii's classification of tumor extent. All patients were operated using a retromastoid suboccipital approach. Postoperative results were analyzed and compared with those of unilateral VS.

RESULTS

The mean age of presentation was 25.7 years. Hearing impairment was the commonest symptom. Headache with features of raised intracranial pressure were present in 10 (62.5%) patients. Giant tumors were present in seven (43.7%) patients; large tumors in eight (50%) and a medium-sized tumor in one (6.3%). Total tumor resection was achieved in 13 patients and subtotal resection in two. One patient was managed conservatively and followed up with serial CT scans. On the contralateral side, one large tumor required total excision. One medium sized tumor underwent sub-capsular excision in an attempt to preserve hearing. The facial nerve was anatomically preserved in seven (46.7%) patients and in one, the cochlear nerve was anatomically preserved. There was no peri-operative mortality.

CONCLUSIONS

Patients with bilateral schwannomas are younger, have larger lesions, poorer preoperative hearing and are more likely to lose either auditory and/or facial nerve function during attempted total resection of the tumor. Classifying the tumors into two groups by extent, that is, tumors extending to the cerebellopontine angle cistern (T1-T3a) and, tumors extending to or compressing the brainstem (T3b to T4b), allows the surgical strategy to be defined.

Severe dysphagia in lower cranial nerve involvement as the initial symptom of Wegener's granulomatosis

We observed a 42-year-old woman presenting with severe dysphagia secondary to paralysis of the lower cranial nerves and right phrenic nerve involvement, followed by respiratory failure. An EMG confirmed bilateral denervation of the 9th, 10th, 11th and 12th cranial nerves and right phrenic nerve. Videolaryngoscopy showed bilateral vocal fold immobility. Anemia, elevated ESR, microhematuria and C-ANCA (PR-3) antibodies were detected. Brain MRI and CSF were normal. A chest CT showed bilateral, irregular pulmonary lesions. An 18F-FDG total body scan showed diffuse hypermetabolic regions in both pulmonary bases, in the mediastinic region and in the rhinopharynx, raising the suspicion of a neoplastic process. A transthoracic biopsy disclosed nodular granulomatous aggregates with multinucleated giant cells, supporting the diagnosis of Wegener's granulomatosis. Immunosuppressive therapy achieved complete clinical resolution and cleared the pulmonary lesions. To the best of our knowledge this is the first report of Wegener's granulomatosis presenting with neurogenic dysphagia due to lower cranial nerve palsy.

Microvascular decompression as a treatment for cranial nerve hyperactive dysfunction--a critical view

Neurovascular compression has been postulated as a probable mechanism for a large number of cranial nerve syndromes, with trigeminal neuralgia (TGN) as the prime example. Microvascular decompression (MVD) is often cited as the procedure of choice for treatment of medically refractory TGN. Arguments against these assumptions are: MRA studies indicate that vascular contact with the trigeminal nerve is present in most healthy individuals. Treatment results of MVD in multiple sclerosis patients with TGN are almost as good (at least in the short term) as in idiopathic cases. MVD is reported to provide pain relief even in TGN patients without visible neurovascular contact . In other syndromes of cranial nerve'hyperactive dysfunction'--vertigo, tinnitus and neurogenic hypertension--the documentation is even weaker.

MRI findings in pediatric ophthalmoplegic migraine: a case report and literature review

Ophthalmoplegic migraine (also recognized as a cranial neuralgia) is a form of migraine characterized by recurrent episodes of headache with ophthalmoplegia related to paresis of cranial nerves III, IV, or VI, with onset typically in childhood. These symptomatic episodes may persist for several hours or for several weeks, months, or permanently. To date, the exact etiology of ophthalmoplegic migraine remains unknown. In previous case reports, ophthalmoplegic migraine may or may not be associated with changes seen on magnetic resonance imaging. Contrast-enhanced magnetic resonance imaging performed during symptomatic and postsymptomatic periods in patients with ophthalmoplegic migraine may hold great value in identifying the pathophysiologic features of oculomotor nerve palsies. Of cases demonstrating abnormal magnetic resonance imaging, a majority show improved but persistent changes on repeat imaging. The present report describes a case of recurrent ophthalmoplegic migraine in a 16-year-old girl. Although the patient presented with ophthalmoplegic migraine during this episode in the same manner as her prior episodes, enhancement of the cranial nerve III on magnetic resonance imaging was evident during the eighth episode whereas previous imaging had been normal. Complete resolution of enhancement of the oculomotor nerve on repeat imaging adds to the few cases that have shown such findings in patients with recurrent ophthalmoplegic migraine. A review of previous reported cases of ophthalmoplegic migraine is offered.

Electric stimulation approaches to the restoration and rehabilitation of swallowing: a review

In recent years, there has been a proliferation of interest in the use of electric stimulation for the treatment of swallowing disorders. This review explores both the rationale and existing evidence for electric stimulation approaches to swallowing rehabilitation. Although this is an exciting area of research which holds promise for future clinically relevant technology and/or therapy, a critical analysis of the existing literature will be presented to support the argument that implementation of electric stimulation in clinical swallowing rehabilitation settings still remains pre-mature.

[Moebius sequence: clinico-radiological findings]

INTRODUCTION

Moebius syndrome is an infrequent congenital, non-progressive disorder that is defined by facial palsy (usually bilateral) and oculomotor compromise. Its clinical spectrum is variable but it affects other cranial nerves and is associated with multiple malformations.

PATIENTS AND METHODS

We report the clinical, neurological and neuroimaging features and the progress of 20 patients (16 males and 4 females) who satisfied diagnostic criteria for Moebius sequence.

RESULTS

Ages at the first visit ranged from 9 days to 23 months. Births had been normal in 50% of the patients. Facial nerve compromise was observed in all cases, 70% being bilateral. Cranial nerves VI (85%), XII (40%), VIII (25%) and IX (60%) were also involved. Perinatal respiratory distress was seen in 35% of the patients, apnoeas in 25% and retarded development in 60% of cases. They also presented other associated malformations such as microretrognathia, ogival palate, club foot, hand and foot malformations, and four cases presented unilateral agenesis of the pectoralis major. An electromyogram study showed absence of spontaneous and voluntary activity and muscle evoked potentials on stimulating the facial nerve; magnetic resonance imaging of the brain showed hypoplasia of the trunk, agenesis of the cranial nerves and abnormalities in the posterior fossa in three of the ten cases in which the scan was performed.

CONCLUSIONS

The association of multiple malformations and dysfunction of the cranial nerves suggests a disruption in the process of morphogenesis during the embryonic period, and therefore Moebius syndrome is considered to be a malformative sequence.

Motor responses of muscles supplied by cranial nerves to subthalamic nucleus deep brain stimuli

The distribution of human corticobulbar motor excitatory and inhibitory output is not fully understood. In particular, it is unclear whether the pattern of innervation is the same for upper and lower facial muscles, and what is the motor cortical area giving rise to such innervation. We used electrodes implanted in the subthalamic nucleus (STN) in patients with Parkinson's disease to activate motor tracts at a subcortical level. We examined the excitatory and inhibitory effects of unilateral single STN deep brain stimulation (sSTN-DBS) in 14 patients by taking recordings from facial, cervical and upper limb muscles on both sides. We measured the latency and amplitude of the motor-evoked potentials (MEPs), and the latency and duration of the silent periods, and compared ipsilateral with contralateral responses and responses obtained in different muscles. Unilateral sSTN-DBS induced strictly contralateral MEPs in the trapezius, deltoid, biceps and thenar muscles. The same stimulus always induced bilateral MEPs in the orbicularis oculi, orbicularis oris, masseter and sternocleidomastoid at a mean latency in the range 6.0-9.1 ms. MEP latencies in the orbicularis oculi and orbicularis oris were significantly longer than in the masseter and sternocleidomastoid (P < 0.01). A short latency small action potential was recorded in the ipsilateral orbicularis oculi that was likely generated by activation of extraocular muscles. During sustained voluntary muscle contraction, a silent period was recorded at similar onset latency on both sides. This period was significantly shorter in orbicularis oculi than in masseter, and in the ipsilateral side for both muscles (P < 0.01). sSTN-DBS is able to activate the descending projecting fibres in the corticobulbar tract eliciting bilateral MEPs and silent periods in facial and cranial muscles. This suggests that fibres to both ipsi- and contralateral motor nuclei descend together at the level of the STN. These findings are relevant in the discussion of the innervation of upper and lower facial muscles in humans and in the interpretation of previous results obtained with transcranial cortical stimulation.

Monitoring motor function during resection of tumours in the lower brain stem and fourth ventricle

OBJECTIVES

Even in the days of modern microsurgery, the removal of a brain stem lesion remains a surgical challenge. Especially when operating on children, the prognosis is directly related to the radicality of the resection; however, a radical resection is often associated with surgical morbidity. Intraoperative neuromonitoring could help to minimise the surgical morbidity, but few studies have been performed to clarify the value of this monitoring. We investigated a prospective series of 21 patients with lesions involving the brain stem for the prognostic value and benefits of neuromonitoring.

METHODS

We performed intraoperative neuromonitoring of cranial nerve function by electromyography (EMG) and motor evoked potential (MEP). The results were correlated with postoperative neurological deficits.

CONCLUSIONS

There is a good correlation between intraoperative neurophysiological events and postoperative neurological deficits in patients with lesions of the brain stem. In general, transient, prolonged, spontaneous activity in EMG is associated with a transient paresis of the respective muscle, whereas a permanent spontaneous activity is associated with a permanent deficit. Intraoperative neuromonitoring reliably predicts postoperative neurological function in patients with tumours of the lower brain stem and fourth ventricle. This neuromonitoring guides the neurosurgeon in the operation and may decrease surgical morbidity. We recommend using monitoring of MEP and EMG of the lower cranial nerves in surgery on all patients with lesions involving the lower brain stem and fourth ventricle.

Neurological causes of taste disorders

In caring for patients with taste disorders, the clinical assessment should include complete examination of the cranial nerves and, in particular, gustatory testing. Neurophysiological methods such as blink reflex and masseter reflex allow the testing of trigeminofacial and trigeminotrigeminal pathways. Modern imaging methods (MRI and computed tomography) enable the delineation of the neuroanatomical structures which are involved in taste and their relation to the bony skull base. From a neurological point of view, gustatory disorders can result from damage at any location of the neural gustatory pathway from the taste buds via the peripheral (facial, glossopharyngeal and vagal nerve) and central nervous system (brainstem, thalamus) to its representation within the cerebral cortex. Etiopathogenetically, a large number of causes has to be considered, e.g. drugs and physical agents, cerebrovascular disorders including dissection of the carotid artery and pontine/thalamic lesions, space-occupying processes - in particular tumors compressing the cerebellopontine angle and the jugular foramen of the skull base - head trauma and skull base fractures, isolated cranial mononeuropathy (e.g. Bell's palsy) or polyneuropathy, epilepsy, dementia, multiple sclerosis and major depression. In addition to this, aging can also lead to diminished taste perception. Due to the broad differential diagnostic considerations, it is essential to look for additional, even mild, neurological signs and symptoms. Treatment must relate to the underlying cause. Zinc may be tried in idiopathic dysgeusia.

Neurostimulation for chronic noncancer pain: an evaluation of the clinical evidence and recommendations for future trial designs

Object

Neurostimulation to treat chronic pain includes approved and investigational therapies directed at the spinal cord, thalamus, periaqueductal or periventricular gray matter, motor cortex, and peripheral nerves. Persistent pain after surgery and work-related or neural injuries are common indications for such treatments. In light of the risks, efforts, costs, and expectations associated with neurostimulation therapies, a careful reexamination of the methods used to gather evidence for this treatment’s long-term efficacy is in order.

Methods

The authors combed English-language publications to determine the nature of the evidence supporting the efficacy of neurostimulation therapies for chronic noncancer pain. To formulate recommendations for the design of future studies, the results of their analysis were compared with established guidelines for the evaluation of medical evidence.

Evidence supporting the efficacy of neurostimulation has been collected predominantly from retrospective series or from prospective studies whose design or methods of analysis make them subject to limited interpretation. To date, there has been no successful clinical study focused on establishing the efficacy of neurostimulation for pain and incorporating sufficient numbers of participants, matched control groups, sham stimulation, randomization, prospectively defined end points, and methods for controlling experimental bias. Currently available data provide little support for the common practices of psychological or pharmacological screening or trial stimulation to predict and/or improve long-term results.

Conclusions

These findings do not diminish the value of previous investigations or positive patient experiences and do not mean that the treatments are ineffective; rather, they reveal that new data are required to answer the questions raised in and by previous study data. Future analyses of emerging neurostimulation modalities for pain should, whenever feasible, require unambiguous diagnoses as an entry criterion and should involve the use of randomization, parallel control groups that receive sham stimulation, and blinding of patients, investigators, and device programmers. Given the chronicity of patient symptoms and stimulation therapies, efficacy should be studied for 1 year or longer after device implantation. Meticulous study methods are especially important to evaluate new therapies like motor cortex and occipital nerve stimulation.

Multiple cranial nerve palsies associated with type 2 diabetes mellitus

Although isolated cranial nerve palsies are common in patients with diabetes mellitus, multiple simultaneous cranial neuropathies are rare. We report a 48-year-old man, a known case of diabetes mellitus, who presented with facial palsy, foot drop and painful ophthalmoplegia of the left eye. The initial differential diagnosis included diabetic polyneuropathy, septic cavernous sinus thrombosis, mucormycosis and the Tolosa Hunt syndrome. Magnetic resonance (MR) imaging findings were consistent with those of the Tolosa Hunt syndrome. The patient had a remarkable complete resolution of his ophthalmoplegia after four weeks of steroid treatment, with repeat MR imaging showing resolution of the initial changes.

[Painful tic convulsif and Botulinum toxin]

INTRODUCTION

Painful tic convulsif is a rare disorder that associates trigeminal neuralgia (TN) and ipsilateral hemifacial spasm (HFS). These two disorders are the most common examples of hyperactive cranial rhizopathy and are frequently caused by vascular compression of these cranial nerves at the nerve root entry and exit zone in the brain stem, which leads to paroxysmal ephaptic transmission.

CASE REPORTS

We report the cases of four patients with combined TN and HFS out of a total of 247 patients with HFS who were treated with botulinum toxin. One patient had TN that was contralateral to the HFS, while the other three were ipsilateral, and one of these had bilateral HFS. In all four cases both the HFS and the TN improved with botulinum toxin treatment.

CONCLUSIONS

These four patients with TN and HFS suggest a common aetiology for the two disorders, due either to central neuronal hyperactivity or to vascular compression of several cranial nerves. The beneficial effect of botulinum toxin in both disorders supports the idea of this toxin having a central mechanism of action that acts by controlling neuronal hyperactivity in the brain stem, as well as its peripheral action.

The Role of the Craniospinal Nerves in Mediating the Antinociceptive Effect of Transcranial Electrostimulation in the Rat

Transcranial electrostimulation (TES) has been reported to elicit significant analgesia, but its mechanism of action has not been elucidated. In a recently introduced clinically relevant rat model of TES we have validated and characterized the TES antinociceptive effect, suggesting involvement of the sensory nerves of the rat's scalp in mediating that effect. In this study, we have further investigated the role of the craniospinal nerves by attempting to block the TES antinociceptive effect with local anesthetic injected under the TES electrodes. We also applied different transcutaneous electrical nerve stimulation modalities through the TES electrodes and compared the elicited antinociceptive effect to that of TES. The antinociceptive effect was assessed by measuring nociceptive thresholds in the tail-flick latency test in awake, unrestrained male rats. Data were analyzed by one-way analysis of variance followed by the Bonferroni t-test. The TES antinociceptive effect was significantly reduced after local anesthetic injection, and administration of 100 Hz transcutaneous electrical nerve stimulation was, over time, capable of eliciting the same degree of antinociceptive effect as TES. We conclude that sensory craniospinal nerves play a critical role in mediating the TES antinociceptive action and offer a hypothesis on the underlying mechanism(s) responsible for this action.