{"title":"Emerging role of clinical neurophysiology in the diagnosis of movement disorders","authors":"Shabbir Hussain I. Merchant","doi":"10.1016/j.cnp.2022.01.003","DOIUrl":"10.1016/j.cnp.2022.01.003","url":null,"abstract":"","PeriodicalId":45697,"journal":{"name":"Clinical Neurophysiology Practice","volume":"7 ","pages":"Pages 49-50"},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2467981X22000051/pdfft?md5=34fb98823038c708cd6e168c450f9170&pid=1-s2.0-S2467981X22000051-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44991528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A test to determine the site of abnormal neuromuscular refractoriness","authors":"Hatice Tankisi , Hugh Bostock , Peter Grafe","doi":"10.1016/j.cnp.2021.11.001","DOIUrl":"10.1016/j.cnp.2021.11.001","url":null,"abstract":"<div><h3>Objective</h3><p>The relative refractory period (RRP) of motor axons is an important parameter in nerve excitability tests of the recovery cycle (RC). Abnormalities may have a site in the axonal membrane, the neuromuscular junction, or in a dysfunction of the muscle. We aimed in this study to determine the site of abnormality, using a modified protocol of the conventional RC test, whereby an additional supramaximal stimulus is added at the same interstimulus interval as in RC recordings (RCSM).</p></div><div><h3>Methods</h3><p>Twenty-four healthy subjects aged 37.8 ± 2.4 years (mean ± SE) were examined with median nerve excitability testing using RC and RCSM protocols at normal temperature (34.1 ± 0.2 °C). The recordings were repeated in 12 subjects after selective cooling of the thenar muscle (25.2 ± 0.7 °C) and in 12 subjects after cooling the nerve trunk at the wrist (24.9 ± 0.3 °C).</p></div><div><h3>Results</h3><p>After cooling the nerve, RRP measured with RC and RCSM were prolonged similarly (medians by 1.8 ms, and 2.1 ms respectively). In contrast, cooling the muscle prolonged RRP measured with RC (by 1.3 ms), but did not significantly prolong RRP measured with RCSM. RRPs measured by RC and RCSM were significantly different when cooling was at the muscle (P = 5.10<sup>-4</sup>), but not when cooling was at the nerve (P = 0.57).</p></div><div><h3>Conclusions</h3><p>A difference between RC and RCSM indicates abnormal excitability distal to the axonal membrane under the stimulating electrode.</p></div><div><h3>Significance</h3><p>Combining RCSM with the conventional RC protocol should help to localize the site of abnormal neuromuscular refractoriness.</p></div>","PeriodicalId":45697,"journal":{"name":"Clinical Neurophysiology Practice","volume":"7 ","pages":"Pages 1-6"},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/07/e9/main.PMC8693356.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39785390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nathan Pavey , Mana Higashihara , Mehdi A.J. van den Bos , Parvathi Menon , Steve Vucic
{"title":"The split-elbow index: A biomarker of the split elbow sign in ALS","authors":"Nathan Pavey , Mana Higashihara , Mehdi A.J. van den Bos , Parvathi Menon , Steve Vucic","doi":"10.1016/j.cnp.2021.11.002","DOIUrl":"10.1016/j.cnp.2021.11.002","url":null,"abstract":"<div><h3>Objective</h3><p>The split elbow sign is a clinical feature of amyotrophic lateral sclerosis (ALS), characterised by preferential weakness of biceps brachii muscle compared to triceps. A novel neurophysiological index, termed the <em>split elbow index (SEI)</em>, was developed to quantify the split-elbow sign, and assess its utility in ALS.</p></div><div><h3>Methods</h3><p>Clinical and neurophysiological assessment was prospectively undertaken on 34 ALS patients and 32 ALS mimics. Compound muscle action potential (CMAP) amplitude was recorded from biceps brachii and triceps muscles from which the SEI was calculated using the following formula:</p><p><span><math><mrow><mi>SEI</mi><mo>=</mo><mfrac><mrow><mi>CMAPamplitudeBICEPSBRACHII</mi></mrow><mrow><mi>CMAPamplitudeTRICEPSBRACHII</mi></mrow></mfrac></mrow></math></span></p></div><div><h3>Results</h3><p>The split elbow sign was significantly more common in ALS patients when compared to ALS mimic patients (P < 0.05). The SEI was significantly reduced in ALS patients when compared to ALS mimics (P < 0.01). This reduction was evident in spinal and bulbar onset ALS. A SEI cut-off value of ≤0.62 exhibited a sensitivity of 71% and specificity of 61%.</p></div><div><h3>Conclusions</h3><p>The split elbow sign is significantly more common in ALS patients, and was supported by a reduction in the SEI.</p></div><div><h3>Significance</h3><p>The SEI may be utilised as a surrogate biomarker of the split elbow sign in future ALS studies.</p></div>","PeriodicalId":45697,"journal":{"name":"Clinical Neurophysiology Practice","volume":"7 ","pages":"Pages 16-20"},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/04/5a/main.PMC8733259.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39816986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Melanie Bergmann, Elisabeth Brandauer, Ambra Stefani, Anna Heidbreder, Iris Unterberger, Birgit Högl
{"title":"The additional diagnostic benefits of performing both video-polysomnography and prolonged video-EEG-monitoring: When and why","authors":"Melanie Bergmann, Elisabeth Brandauer, Ambra Stefani, Anna Heidbreder, Iris Unterberger, Birgit Högl","doi":"10.1016/j.cnp.2022.02.002","DOIUrl":"10.1016/j.cnp.2022.02.002","url":null,"abstract":"<div><h3>Objective</h3><p>Video-polysomnography (VPSG) and prolonged video-EEG-monitoring (pVEEG-M) are neurophysiological investigation modalities. Depending on indication either is performed, but occasionally patients undergo both (during the same or separate stays). We sought to assess the reasons and potential benefits of dual diagnostic assessments with both modalities.</p></div><div><h3>Methods</h3><p>A retrospective chart-review was performed to identify patients who underwent both VPSG and pVEEG-M during the 10 year period between 2007 and 2017. One-hundred-nine patients were identified who had undergone both studies. Patients were grouped according to indication and outcome.</p></div><div><h3>Results</h3><p>One-hundred-nine patients had both, a VPSG and pVEEG-M, in 62 (56.9%) the studies were performed because of separate diagnoses independent from each other. In 47 patients (43.1%) investigation with both modalities was needed to clarify the suspected diagnosis or to refute differential diagnoses. Out of these 47, 11 (10.1% of the whole group) arrived a new final diagnosis whereas in 36 (33%) the primary diagnosis was corroborated with the second modality.</p></div><div><h3>Conclusions</h3><p>In the majority of cases VPSG plus pVEEG-M were indicated to diagnose or monitor different comorbid diseases (e.g. sleep-related breathing disorder and epilepsy). In the other cases, performing both modalities was useful to achieve a higher diagnostic accuracy or to refute differential diagnoses.</p></div><div><h3>Significance</h3><p>VPSG and pVEEG-M are neurophysiological investigations which complement each other, especially in case of two different comorbid diseases in a single patient, to rule out differential diagnosis or when a higher diagnostic certainty is seeked.</p></div>","PeriodicalId":45697,"journal":{"name":"Clinical Neurophysiology Practice","volume":"7 ","pages":"Pages 98-102"},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/d4/e7/main.PMC8938868.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40325323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A.W.G Buijink , D.A. Piña-Fuentes , M.J. Stam , M. Bot , P.R. Schuurman , P. van den Munckhof , A.F. van Rootselaar , R.M.A. de Bie , M. Beudel
{"title":"Thalamic local field potentials recorded using the deep brain stimulation pulse generator","authors":"A.W.G Buijink , D.A. Piña-Fuentes , M.J. Stam , M. Bot , P.R. Schuurman , P. van den Munckhof , A.F. van Rootselaar , R.M.A. de Bie , M. Beudel","doi":"10.1016/j.cnp.2022.03.002","DOIUrl":"10.1016/j.cnp.2022.03.002","url":null,"abstract":"<div><h3>Background</h3><p>Essential tremor (ET) is one of the most common movement disorders, and continuous deep brain stimulation (DBS) is an established treatment for medication-refractory cases. However, the need for increasing stimulation intensities, with unpleasant side effects, and DBS tolerance over time can be problematic. The advent of novel DBS devices now provides the opportunity to longitudinally record LFPs using the implanted pulse generator, which opens up possibilities to implement adaptive DBS algorithms in a real-life setting.</p></div><div><h3>Methods</h3><p>Here we report a case of thalamic LFP activity recorded using a commercially available sensing-enabled DBS pulse generator (Medtronic Percept PC).</p></div><div><h3>Results</h3><p>In the OFF-stimulation condition, a peak tremor frequency of 3.8 Hz was identified during tremor evoking movements as assessed by video and accelerometers. Activity at the same and supraharmonic frequency was seen in the frequency spectrum of the LFP data from the left vim nucleus during motor tasks. Coherence analysis showed that peripherally recorded tremor was coherent with the LFP signal at the tremor frequency and supraharmonic frequency.</p></div><div><h3>Conclusion</h3><p>This is the first report of recorded tremor-related thalamic activity using the electrodes and pulse generator of an implanted DBS system. Larger studies are needed to evaluate the clinical potential of these fully implantable systems, and ultimately pulse generators with sensing-coupled algorithms driving stimulation, to really close the loop.</p></div>","PeriodicalId":45697,"journal":{"name":"Clinical Neurophysiology Practice","volume":"7 ","pages":"Pages 103-106"},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2467981X22000129/pdfft?md5=44b407396804d4d3bb0c2c692fd3c311&pid=1-s2.0-S2467981X22000129-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48945079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Christine Van Winssen, Paulina Kyriakopoulos, Farah El Sadi, Arezoo Rezazadeh, Tadeu Fantaneanu
{"title":"Integrating virtual EEG sessions into fellowship programs during the COVID-19 pandemic","authors":"Christine Van Winssen, Paulina Kyriakopoulos, Farah El Sadi, Arezoo Rezazadeh, Tadeu Fantaneanu","doi":"10.1016/j.cnp.2022.03.001","DOIUrl":"10.1016/j.cnp.2022.03.001","url":null,"abstract":"","PeriodicalId":45697,"journal":{"name":"Clinical Neurophysiology Practice","volume":"7 ","pages":"Pages 96-97"},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2467981X22000117/pdfft?md5=27f540242aa21c27f9312cfa0b7810cc&pid=1-s2.0-S2467981X22000117-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46201226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yared Z. Zewde, Biniyam A. Ayele, Hanna D. Belay, Dereje M. Oda, Meron A. G/Wolde, Yohannes D. Gelan, Fikru T. Kelemu, Seid A. Gugssa, Abenet T. Mengesha
{"title":"Electrodiagnostic referrals and neuromuscular disease pattern in East Africa: Experience from a tertiary hospital in Ethiopia","authors":"Yared Z. Zewde, Biniyam A. Ayele, Hanna D. Belay, Dereje M. Oda, Meron A. G/Wolde, Yohannes D. Gelan, Fikru T. Kelemu, Seid A. Gugssa, Abenet T. Mengesha","doi":"10.1016/j.cnp.2022.02.001","DOIUrl":"10.1016/j.cnp.2022.02.001","url":null,"abstract":"<div><h3>Objective</h3><p>We present a retrospective cross-sectional review of the electrodiagnostic (EDX) referral and diagnostic patterns in patients with suspected neuromuscular conditions at a tertiary hospital in Ethiopia.</p></div><div><h3>Methods</h3><p>Between 2016 and 2019, 313 patients were evaluated at the EDX lab in Tikur Anbessa Specialised Hospital, Addis Ababa, Ethiopia. In our patients, nerve conduction study and when appropriate needle electromyography was done. Demographic and clinical data were extracted from a digital registry.</p></div><div><h3>Results</h3><p>Polyneuropathy (19.8%), carpal tunnel syndrome (12.1%), and lumbosacral radiculopathy (9.9 %) were the top three reasons for EDX referral in Ethiopia. Among them, polyneuropathy was the most frequent electrodiagnosis, where diffuse axonal and demyelinating subtypes accounted for 54% and 18.8%, respectively. Guillain-Barre syndrome was suspected in 18 patients and 15 had EDX confirmed motor axon polyneuropathy while three patients had demyelinating variant. Although a quarter (26.2%) of the referrals had a normal EDX, abnormal test results were significantly associated with weakness (95% CI: 3.29–7.04, p < 0.001), bound to wheelchair (95% CI: 1.86–2.87, p = 0.01) and having a specific diagnosis at time of referral (95% CI: 2.53–4.68, p = 0.007).</p></div><div><h3>Conclusions</h3><p>Diffuse and entrapment neuropathies were the main reasons for electrodiagnosis test referrals in Ethiopia. Also, motor axonal variant was the most common type of inflammatory polyneuropathy diagnosed with EDX.</p></div><div><h3>Significance</h3><p>Proper patient evaluation and documentation significantly improves the diagnostic yield and cost-effectiveness of EDX testing in a resource-poor countries like Ethiopia. This might be achieved through educating medical students, residents, and other care providers on the basics of EDX and its indications for correct use in the clinical care.</p></div>","PeriodicalId":45697,"journal":{"name":"Clinical Neurophysiology Practice","volume":"7 ","pages":"Pages 65-70"},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/58/8b/main.PMC8924510.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40308376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Are nerve conduction studies altered in functional neurological disorders?","authors":"Eglė Sukockienė, Frédéric Assal, Annemarie Hübers","doi":"10.1016/j.cnp.2022.05.003","DOIUrl":"10.1016/j.cnp.2022.05.003","url":null,"abstract":"<div><h3>Background</h3><p>Functional neurological disorders represent conditions without a readily identifiable origin or laboratory-supported diagnostic. We report a case of functional neurological disorder, presenting with muscle weakness with alterations in F-waves on the affected side.</p></div><div><h3>Case report</h3><p>A retrospective case review of a patient seen in clinic. Electrophysiological evaluation included nerve conduction studies, including recording of F-waves in lower limbs, and needle EMG. A patchy sensory loss and unilateral muscle weakness of the left lower limb persisted nine days after a 40-year-old female patient developed bilateral lower limb weakness following a laparoscopic surgery. MRI was negative for radicular compression, myelopathy, or lumbosacral plexopathy. F-waves of the peroneal and tibial nerves on the left were absent or of reduced persistence and amplitude compared to the asymptomatic right side.</p></div><div><h3>Significance</h3><p>The observation of unilateral alterations of F-wave parameters could be interpreted as an asymmetrical decrease of alpha motor neuron excitability on L4 – S2 segments. In the absence of peripheral nervous system dysfunction or a structural lesion, the results here suggest a central control dysfunction or point to a more complex peripheral role. Further research is necessary to determine the frequency of these findings in a larger group of patients while incorporating other late responses, such as H (Hoffman) reflex, and measures of cortical excitability.</p></div>","PeriodicalId":45697,"journal":{"name":"Clinical Neurophysiology Practice","volume":"7 ","pages":"Pages 166-168"},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/65/31/main.PMC9214718.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40402419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}