Jaw Jerk Research Articles

The p.D417N variant of TUBB4A as a possible cause of hereditary spastic paraplegia: a case report

BackgroundTubulins are dimeric proteins expressed in all eukaryotic cells, serving as the fundamental building blocks of microtubule filaments. The TUBB4A gene encodes the protein β-tubulin. Mutations of TUBB4A have been associated with two neurodegenerative diseases with very different clinical characteristics: dystonia type 4 (DYT4) and Hypomyelination with Atrophy of the Basal Ganglia and Cerebellum (H-ABC). Several cases of patients with H-ABC or unclassified leukoencephalopathy show spastic ataxia with or without leukodystrophy in association with mutations in exon 5 of TUBB4A gene.Case presentationWe report the case of a 65-year-old woman who has been complaining of progressive difficulty in walking since childhood. The neurological examination revealed, among all, a spastic gait, difficulties in standing on the toes and heels, brisk deep tendon reflexes at upper limbs, clonic patellar reflexes, brisk ankle reflexes, as well as bilateral Babinski and Hoffmann sign, brisk jaw jerk and severe lower limb spasticity. NGS studies for inherited cases of spastic paraplegia revealed a novel variant of unknown significance (VUS) (c.1249A > G, p.D417N), in TUBB4A. To the best of our knowledge, this variant has not been reported in the literature or any databases in association with these diseases.ConclusionWe report the case of a patient carrying a variant of uncertain significance (VUS) of the TUBB4A gene, showing a progressive, spastic paraparesis, supporting the extension of the phenotypic spectrum up to include spastic paraplegia.

Upper motor neuron signs in primary lateral sclerosis and hereditary spastic paraplegia.

The frequency and distribution of upper motor neuron (UMN) signs in primary lateral sclerosis (PLS) are unknown. We aimed to study the spectrum of UMN signs in PLS and compare it with hereditary spastic paraplegia (HSP). We retrospectively analyzed the frequency of different UMN signs, including hyperreflexia (limbs and jaw), limb and tongue spasticity, Babinski, and Hoffman signs, in PLS patients at first observation and compared this respect to onset region and symptom duration. We also compared PLS versus HSP patients. We included 34 PLS and 20 HSP patients, with a median symptom duration at first visit of 3.0 (interquartile range, IQR = 4.0) and 19.0 (IQR = 22.0) years, respectively. In PLS patients, hyperreflexia of upper (UL) (88.2%) and lower (LL) (91.2%) limbs, and LL spasticity (79.4%) were the most common findings. Spasticity of LL was significantly (p = .012) more frequent in LL-spinal onset subgroup, tongue spasticity in bulbar-onset subgroup (p = .021), and Hoffman sign in UL-spinal onset subgroup (p = .024). The PLS subgroup with shorter disease duration had a higher frequency of abnormal jaw jerk reflex (p = .037). Compared with HSP, PLS patients had a higher frequency of UL hyperreflexia (88.2% vs. 42.1%, p < .001) and UL spasticity (44.1% vs. 0.0%, p < .001). Asymmetric distribution of UMN signs was present in PLS and not in HSP. In PLS, UL UMN signs are nearly always present and UMN sign distribution appears to be associated with onset region. At first observation, bulbar involvement, asymmetrical distribution of UMN signs and UL spasticity may indicate PLS versus HSP.

Periodontal Mechanoreceptors Stimulated Study of Human Masseter Reflex Control Prior and During Fixed and Functional Orthodontic Appliance Therapy

Periodontal Mechanoreceptors Stimulated Study of Human Masseter Reflex Control Prior and During Fixed and Functional Orthodontic Appliance Therapy

662 Bilateral Vocal Cord Paralysis and Cranial Polyneuropathy: A Rare Presentation of Ramsay Hunt Syndrome

Abstract Case Presentation A 61-year-old gentleman with chronic lymphocytic leukaemia presented with right sided disseminated vesicles, otalgia, hearing loss, facial weakness, dysphagia, hoarseness, breathlessness, and stridor. In the preceding 48 hours he had two A&amp;E presentations with only right otalgia, facial weakness, throat tightness and mild breathlessness. Cranial nerve (CN) examination demonstrated right cheek numbness and absent jaw jerk reflex (CNV), right grade 6 lower motor neuron facial palsy (CNVII), impaired hearing (CNVIII), dysphonia, dysphagia, and asymmetric palate elevation (CNIX and X). Fibreoptic nasendoscopy (FNE) demonstrated bilateral vocal cord palsy. He was diagnosed with Ramsay Hunt syndrome (RHS) and disseminated herpes zoster (HZ) requiring intubation and ventilation, intravenous steroids, aciclovir, antibiotics and a prolonged intensive care admission. He was discharged after three months. Eight months later, he has a long-term tracheostomy, gastrostomy, and live-in carer. Discussion This is the only case found in the literature of RHS and associated bilateral vocal cord palsy with cranial polyneuropathy requiring a long-term tracheostomy. It highlights the significant morbidity attached with RHS complications, particularly in a patient with underlying malignancy. Awareness of these rare and potentially life-threatening complications should be raised to avoid investigation and treatment delay. HZ should be considered in patients with CNVII palsy and otalgia, with or without vesicles. Clinicians should perform full CN examination including FNE to assess for cranial polyneuropathy. RHS can present without vesicles, making it indistinguishable from Bell's Palsy. Therefore, we should consider treating Bell's Palsy with aciclovir. Furthermore, multidisciplinary management of disseminated HZ is essential.

Alterations in blink and masseter reflex latencies in older adults with neurocognitive disorder and/or diabetes mellitus.

BACKGROUNDBlink and masseter reflexes provide reliable, quantifiable data on the function of the central nervous system: Delayed latencies have been found in patients with neurocognitive disorder (ND) and type 2 diabetes mellitus (T2DM), but this has not been studied in patients with both pathologies.AIMTo investigate if older adults with ND plus T2DM have prolonged latencies of blink and masseter-reflex and if they were associated with disease progression.METHODSThis cross-sectional study included 227 older adults (> 60 years) from Colima, Mexico. Neurocognitive disorder was identified by a neuropsychological battery test, and T2DM identified by medical history, fasting glucose, and glycosylated hemoglobin. Latencies in the early reflex (R1), ipsilateral late (R2), and contralateral late (R2c) components of the blink reflex were analyzed for all subjects, and 183 subjects were analyzed for latency of the masseter reflex. RESULTSIn 20.7% of participants, ND was detected. In 37%, T2DM was detected. Latencies in R1, R2, and R2c were significantly prolonged for groups with ND plus T2DM, ND, and T2DM, compared with the control group (P < 0.0001). The masseter reflex was only prolonged in older adults (regardless of T2DM status) with ND vs controls (P = 0.030). In older adults with ND and without T2DM, the more the cognitive impairment progressed, the more prolonged latencies in R2 and R2c presented (P < 0.01).CONCLUSIONThese findings suggest that blink and masseter reflexes could be used to evaluate possible changes in brainstem circuits in older adults with ND and T2DM.

Chapter 10 - Monitoring cerebellopontine angle and skull base surgeries

Cerebellopontine angle (CPA) surgery represents a challenge for neurosurgeons due to the high risk of iatrogenic injury of vital neurological structures. Therefore, important efforts in improving the surgical techniques and intraoperative neurophysiology have been made in the last decades. We present a description and review of the available methodologies for intraoperative neuromonitoring and mapping during CPA surgeries. There are three main groups of techniques to assess the functional integrity of the nervous structures in danger during these surgical procedures: (1) Electrical identification or mapping of motor cranial nerves (CNs), which is essential in order to locate the nerve in their different parts during the tumor resection; (2) Monitoring, which provides real-time information about functional integrity of the nervous tissue; and (3) Brainstem reflexes including blink reflex, masseteric reflex, and laryngeal adductor reflex. All these methods facilitate the removal of lesions and contribute to notable improvement in functional outcome and permit on the investigation of their physiopathology in certain neurosurgically treated diseases. Such is the case of hemifacial spasm (HFS). We describe the methodology to evaluate the efficacy of microvascular decompression for HFS treatment at the end of this chapter.

Electrophysiological assessment of the cranial reflexes

Electrophysiological assessment methods play a key role in the diagnosis of various neurological disorders. Electrophysiological evaluation of cranial reflexes is particularly valuable for neurologists. This article provides an overview of electrophysiological evaluation methods for cranial reflexes, which are most commonly used in clinical practice. They provide objective assessment of the functional integrity of nervous system structures that make up the cranial reflex arc, identify the level and, in some cases, the nature of disease, as well as pathophysiological mechanisms of central and peripheral nervous system disorders. We describe the instruments and main approaches to analysing the results for the standard blink reflex, blink reflex with prepulse inhibition, blink reflex with paired stimuli and recovery curve evaluation, reflex inhibition of the levator palpebrae superioris, jaw jerk reflex, and reflex inhibition (cutaneous silent period) of the masseter muscle.

Infantile Ascending Hereditary Spastic Paralysis with Extrapyramidal and Extraocular Manifestations Associated with a Novel ALS2 Mutation.

Infantile Ascending Hereditary Spastic Paralysis with Extrapyramidal and Extraocular Manifestations Associated with a Novel ALS2 Mutation.

Ataxia and Parkinsonism in a Woman With a VCP Variant and Long-Normal Repeats in the SCA2 Allele.

We present the case of a 46-year-old woman with gradually progressive ataxia, parkinsonism, and neuropathy. Symptoms started at age 29 years with speech impairment and difficulty walking. At presentation, she had mild midline ataxia and dysarthria. Left hand rest tremor began at age 33 years. Over the next decade, she developed parkinsonism and lower extremity weakness, which was more prominent than ataxia (Videos 1 and 2 ). Her parkinsonism was responsive to levodopa, and over time, she developed motor fluctuations. She also developed urinary retention and constipation. Medical history was otherwise notable for lumbar radiculopathy, ankylosing spondylitis, elevated anti-nuclear antibodies, migraine, and depression. Current examination reveals appendicular and gait ataxia, dysarthria, parkinsonism (left predominant), bilateral hip flexor weakness and foot drop, length-dependent decrease in pinprick sensation, and hyperreflexia (bilateral Babinski and jaw jerk reflexes). She is adopted and has 2 healthy teenaged sons. She is apparently of European descent but does not know her family history. The authors thank Christopher Gomez, MD, PhD (University of Chicago, IL), for providing ataxia exome and RFC-1 expansion data and discussing the case.

101 Amyotrophic Lateral Sclerosis (ALS) - Not Just a Motor Disease? Isolated Bitter and Sweet Taste Loss in ALS

Specific taste quality deficits in ALS has not heretofore been described. Case Study: A 71 year old right handed female presented with a two year course of progressive reduction in strength in her hands, arms and legs with difficulty tying shoe laces, opening jars, writing and walking. She described nocturnal muscle spasms involving all extremities. Gradually, over eight months prior to presentation, all food began to taste bad and horribly bitter. Associated with no appetite and a seven pounds weight loss. Abnormalities in Neurological examination: Cranial Nerve (CN) examination: CN IX and X: Gag absent bilaterally. Motor examination: Bulk: atrophy in thenar and hypothenar eminences and intrinsics in both upper extremities. Percussion induced fasciculation and myotonia in both shoulders and arms. Fasciculation of tongue with percussion myotonia of tongue. Strength: Intrinsic 4/5 in both upper extremities, 3/5 in abductor policis brevis bilaterally, 3/5 right gastrocnemius soleus, 4/5 bilateral anterior tibialis. Drift testing: left abductor digiti minimi sign. Gait: Heel and toe walking unstable with circumduction of left leg. Tandem gait unstable. Cerebellar: Holmes rebound phenomena positive in the left upper extremity. Deep tendon reflexes: 1+ left brachioradialis. 1+ left triceps. 3+ right ankle jerks. 0 left ankle jerk. Positive jaw jerk. Chemosensory Testing: Normosmia to: Alcohol Sniff Test (46), Pocket Smell Test (3/3) and Retronasal Smell Index (9). Taste Quadrant Testing: ageusia in the palate to sodium chloride and citric acid. Ageusia throughout the palate, tongue and whole mouth to sucrose and quinine hydrochloride. Fungiform papillae count: left 18, right 20 (normal). Lip biopsy (normal). MRI: T2 flair in bilateral corticospinal tracts, left greater than right in the spinal cord and the brain. EMG: fibrillation, positive waves with fasciculation in all four extremities. Voluntary contraction with polyphasic unstable motor unit action potentials. While Lang found no taste loss in ALS (Lang, 2011), Pelletier found reduction in intensity of taste to all modalities in different sectors of the tongue, but paradoxically demonstrated normogeusia in whole mouth taste perception (Pelletier, 2013). Pathological specimens of those with ALS revealed degeneration in the nucleus parabrachialis medialis and tractus trigeminothalamicus dorsalis (Oyanagi, 2015), suggesting that taste deficit may be due to central white matter abnormalities. Sweet taste is localized in the most posterior and rostral aspect of the right insular cortex, immediately adjacent to bitter (Prinster, 2017), suggesting a neighborhood effect phenomena. Weight loss in ALS may be due to sensory distortion and secondary impairment of appetite. It would be worthwhile to investigate those with ALS for evidence of otherwise overlooked gustatory deficits, correction of which may improve appetite and nutritional state.

Pseudo Bulbar Palsy a Rare NEURO-COVID Presentation

Background: The Global pandemic of COVID-19 with more than half million people passed away from their families tragically, wide variety of signs and symptoms resulted from this Novel SARS Cov2 virus. Although the respiratory and Gastro-intestinal symptoms are dominant, however, neurological symptoms whether specific or nonspecific have been reported. Till now the extents of knowledge regarding the neurological sequel of COVID-19 infection are finite. Pseudo Bulbar Palsy is a neurological disease characterised by dysarthria, dysphagia, facial and tongue weakness in addition to emotional liability resulted from an upper motor neuron lesion in the corticoid bulbar tracts. Peripheral neuropathy, Demyelisation and vascularise are underlying aetiologies. This will result in deglutition, and speech disturbance. Case presentation: 60 years old male from Najaf, went to the emergency department with three days history of drowsiness and anorexia after COVID-19 related fever and myalgias. He had significant risk factors. He had 2 weeks fever following a contact with COVID-19 patient. Examination revealed drowsiness, dehydration, the patient was not aware for time and place, eye refluxes was symmetrical. The face was normal with exaggerated jaw jerk CT of the chest showed evidence of COVID-19 infection confirmed by positive PCR. Brain CT showed only brain atrophy without signs of localised ischemia. Farther blood investigations confirm activity of infection. During this the patient developed tonic clonic convulsion required anticonvulsant therapy; he remained semiconscious, with difficulty to swallow and dysarthria, Irritability, drowsiness and disorientation. He received anticoagulant, Steroids, mannitol. The condition improved and the patient discharged in better condition with two weeks anticoagulation. Discussion: this is a story for a rare complication belong to COVID-19 infection, treated as a stroke, as mention in literatures, many recorded cases of Neurocovid that required treatment accordingly. Conclusion: neurological symptoms of COVID-19are extreme and might be nonspecific but some time life threatening, these might overlap severe infection. The improvement in the neurological sequel overlap the COVID-19 improvement both clinical aspect and investigation.

Differential Diagnosis of Chronic Neuropathic Orofacial Pain: Role of Clinical Neurophysiology.

Orofacial pain syndromes encompass several clinically defined and classified entities. The focus here is on the role of clinical neurophysiologic and psychophysical tests in the diagnosis, differential diagnosis, and pathophysiological mechanisms of definite trigeminal neuropathic pain and other chronic orofacial pain conditions (excluding headache and temporomandibular disorders). The International Classification of Headache Disorders 2018 classifies these facial pain disorders under the heading Painful cranial neuropathies and other facial pains. In addition to unambiguous painful posttraumatic or postherpetic trigeminal neuropathies, burning mouth syndrome, persistent idiopathic facial and dental pain, and trigeminal neuralgia have also been identified with neurophysiologic and quantitative sensory testing to involve the nervous system. Despite normal clinical examination, these all include clusters of patients with evidence for either peripheral or central nervous system pathology compatible with the subclinical end of a continuum of trigeminal neuropathic pain conditions. Useful tests in the diagnostic process include electroneuromyography with specific needle, neurography techniques for the inferior alveolar and infraorbital nerves, brain stem reflex recordings (blink reflex with stimulation of the supraorbital, infraorbital, mental, and lingual nerves; jaw jerk; masseter silent period), evoked potential recordings, and quantitative sensory testing. Habituation of the blink reflex and evoked potential responses to repeated stimuli evaluate top-down inhibition, and navigated transcranial magnetic stimulation allows the mapping of reorganization within the motor cortex in chronic neuropathic pain. With systematic use of neurophysiologic and quantitative sensory testing, many of the current ambiguities in the diagnosis, classification, and understanding of chronic orofacial syndromes can be clarified for clinical practice and future research.

Inter-rater reliability of primitive signs in dementia

ObjectivesThe aim of the present study is to explore inter-rater reliability of primitive signs in a group of patients assessed for dementia. Patients and methods97 patients admitted to our University Hospital for cognitive impairment were enrolled in the study. The mean age was 73.04 ± 8.68 (53 females and 44 males). All patients were examined by two cognitive neurologists in a blind fashion. The grasp reflex, the snout reflex, the glabella tap reflex and the palmomental reflex were elicited according to the current literature. Moreover, we add a stretch reflexes (the masseter reflex) to our battery. ResultsThe most frequent primitive reflex was the palmomental reflex followed by the glabella tap, snout, and grasp. The inter-rater reliability was measured for each primitive reflex: grasp reflex (0.884) have a strong correspondence; the glabella tap (0.556), the palmomental (0.516) and the snout reflex (0.445) have otherwise a weak correspondence. The masseter reflex reaches a moderate agreement (0.662). All the measurements reached statistical significance (p < 0.005). ConclusionThe results of the study show weak to substantial agreement for primitive signs and the masseter reflex as expressed by the low-to-high kappa values.

Trigeminal neuralgia as a presenting symptom of brain metastasis in advanced stage of breast cancer

Trigeminal neuralgia is defined as sudden, usually unilateral, severe, brief, stabbing, recurrent episodes of pain in the distribution of one or more branches of the trigeminal nerve. We report a case of trigeminal neuralgia which was a presenting symptom for the diagnosis of brain metatstasis in a patient with advanced stage of breast cancer. A 51 old female complained of right facial pain. She had been diagnosed invasive ductal carcinoma one year ago. Since the detection of cancer, she had multiple metastasis in bone, both lung and chest wall. Brief recurrent lanscinating right facial pain was persisted during 7 days without relief. On admission, pain was distributed in maxillary and mandibular division of trigeminal nerve. Neurologic examination revealed no contraction of masseter and temporalis on the same side. Hypestheia was accompanied in right maxillary and mandibular branch of trigeminal nerve. Brain MRI depicted multiple metastasis in right cavernous sinus, Meckel’s cave and bilateral cerebellum. Neurophysiologic study showed normal blink reflex response, but no potential for masseter reflex test. She was diagnosed with secondary trigeminal neuralgia and we prescribed oxcarbazepine with palliative chemotherapy. Malignant metastasis involving the path of trigeminal nerve could elicit neuralgic pain as a secondary cause of trigeminal neuralgia. In our patient, the neuralgic pain in the area of trigeminal nerve was the only presenting symptom of brain metastasis. Secondary cause of trigeminal neuralgia should be evaluated with extensive brain imaging especially in patient with cancer.

Vestibulo masseteric reflex and acoustic masseteric Reflex. Normative data and effects of age and gender

ObjectiveTo provide normative data for the Vestibulo-Masseteric Reflex (VMR) and Acoustic-Masseteric Reflex (AMR) in healthy subjects, stratified for age and gender. MethodsA total of 82 healthy subjects (M:F 43:39, mean age 39.3 ± 18.4 years, range 13–79 years) underwent recording of click-evoked VMR and AMR (0.1 ms duration, 5 Hz frequency) from active masseter muscles. Masseter responses to uni- and bilateral stimulation were recorded in a zygomatic and a mandibular configuration, according to the position of the reference electrode. Stimulation intensity curves were recorded for each reflex in ten subjects (mean age 20.7 ± 8.1 years). Gender effect was investigated in 62 subjects and age effect was analyzed in six 10-subject groups aged from <25 to >65 years. Onset and peak latencies, interpeak intervals, raw and corrected amplitudes, latency and amplitude asymmetries were analyzed. ResultsVMR had a higher elicitation rate than AMR. For both reflexes, rates of elicitation, and corrected amplitudes were higher in the zygomatic configuration, and bilateral stimulation elicited larger responses. Best acoustic ranges of elicitation were 98–113 dB for AMR and 128–138 dB for VMR. Reflex latencies were shorter in females than males. Frequency and amplitude of VMR and AMR decreased substantially over 55 year olds. ConclusionsVMR and AMR can be easily performed in any clinical neurophysiology laboratory. SignificanceThese reflexes can find application in the investigation of brainstem function in central neurological disorders.

A CASE OF READING EPILEPSY IN A PATIENT HAVING IDIOPATHIC GENERALIZED EPILEPSY

Reflex seizures are defined as epileptic events that are triggered only by specific stimuli which can be external or complex internalmental processes. Reading epilepsy is one such rare form of reflex epilepsy. In primary reading epilepsy, typical attacks are jaw jerks(clicking sensation or stammering), that may evolve into GTCS if reading continues. As reading epilepsy is task-specific, they aregenerally misdiagnosed as non-epileptic and thought to be due to stress related to studies. We report the case of a young male whohave jaw jerks along with blank staring spells while reading which was misdiagnosed as pseudoseizures. This rare case highlights thiseasily treatable benign reflex epilepsy syndrome.

A Clinicopathologic Case Report of a Female with Valosin-Containing Protein (VCP) Gene Mutation Related Disease

Valosin Containing Protein (VCP) gene mutations have been reported in ~1-2% of familial amyotrophic lateral sclerosis (ALS). We report a case of clinically defined and neuropathologically confirmed ALS in a 48-year-old, emaciated female with a p.R155C (c.463 C > T) mutation in VCP gene. She presented with progressive generalized muscular weakness, weight loss, dyspnea on exertion, combined nasal and spastic dysarthria, positive jaw jerk and exaggerated gag reflex.

P115. Painful mydriasis as the only clinical sign of an ipsilateral midbrain abscess

History A 39-year-old man noted increasing right frontal and right retroorbital pain. After 3 days, he also noted blurred vison in the right eye. On clinical examination, he had a mydriatic right pupil with diminished light reaction but otherwise normal findings including eye movements examination (and direct-current electro-oculography). Findings Masseter reflex testing disclosed an increased latency on the right side and was interpreted in favor of an ipsilateral mesencephalic lesion. MRI documented an abscess in the left ventral midbrain involving the region of the distal intra-mesencephalic segment of the 3rd nerve. Cerebrospinal fluid analysis revealed 185 leucocytes/ μ l, mildly elevated total protein (536 g/l), and normal glucose and lactate levels. There was no serological evidence for neuroborreliosis, neurolues, brucellosis, leptospirosis, echinococcosis, or fungal infections. Transesophageal echocardiography and dental and otolaryngological examinations were normal. Treatment He was treated with a combination of ceftriaxone (2 × 2 g/d) plus flucloxacillin (4 × 2 g/d) plus metronidazole (3 × 500 mg/d) for 6 weeks, and for another 6 weeks with cotrimoxazole (800 mg sulfamethoxazole + 160 mg trimethoprim twice daily). During the first 2 weeks antibiotic treatment was accompanied by dexamethasone (initial bolus of 40 mg i.v. followed by 4 × 8 mg/d, which was slowly tapered within 2 weeks). Clinical course Complete clinical recovery occurred within 2 weeks and CSF was normal after 15 days (4 leukoctes/ μ l, total protein: 228 g/l) Conclusion Painful unilateral mydriais may be the only clinical sign of an ipsilateral midbrain lesion.

Reevaluation of reflex responses of the human masseter muscle to electrical lip stimulation.

We examined the reflex response of the human masseter muscle to electrical stimulation of the lip using both single motor unit and surface electromyogram based methods. Using the classical analysis methods, reflex response to mild electrical stimuli generated two distinct short-lasting inhibitions. This pattern may reflect the development of combinations of short- and long-latency inhibitory postsynaptic potentials as a result of the mildly painful electrical lip stimulation. However, this pattern appearing in the classical analysis methods may have developed as a consequence of earlier responses and may not be genuine. This study examined the genuineness of these responses using both the classical analysis methods and the discharge rate method to uncover the realistic postsynaptic potentials in human trigeminal motor nucleus. Using the discharge rate method, we found that the electrical lip stimulation only generated a long-lasting single or compound inhibitory response that is followed by late, long-lasting excitation. These findings have important implications on the redrawing of the neuronal pathways of the trigeminal nerve that are frequently used to judge neuromuscular disorders of the trigeminal region.NEW & NOTEWORTHY We examined the human masseter reflex response to electrical stimulation of lower lip to uncover realistic postsynaptic potentials in the trigeminal motor nucleus. We found that the stimulation generates a long-lasting single or compound inhibitory response that is followed by a late, long-lasting excitation. These findings have important implications on the redrawing of the neuronal pathways of the trigeminal nerve that are frequently used to judge neuromuscular disorders of the trigeminal region.

A neurophysiological study of facial numbness in multiple sclerosis: Integration with clinical data and imaging findings

ObjectiveTo integrate neurophysiological findings with clinical and imaging data in a consecutive series of multiple sclerosis (MS) patients developing facial numbness during the course of an MS attack. MethodsNine consecutive patients with MS and recent-onset facial numbness were studied clinically, imaged with routine MRI, and assessed neurophysiologically with trigeminal somatosensory evoked potential (TSEP), blink reflex (BR), masseter reflex (MR), facial nerve conduction, facial muscle and masseter EMG studies. ResultsAll patients had unilateral facial hypoesthesia on examination and lesions in the ipsilateral pontine tegmentum on MRI. All patients had abnormal TSEPs upon stimulation of the affected side, excepting one that was tested following remission of numbness. BR was the second most sensitive neurophysiological method with 6/9 examinations exhibiting an abnormal R1 component. The MR was abnormal in 3/6 patients, always on the affected side. Facial conduction and EMG studies were normal in all patients but one. ConclusionsFacial numbness was always related to abnormal TSEPs. A concomitant R1 abnormality on BR allowed localization of the responsible pontine lesion, which closely corresponded with MRI findings. We conclude that neurophysiological assessment of MS patients with facial numbness is a sensitive tool, which complements MRI, and can improve lesion localization.