Proposal of surface electromyography signal acquisition protocols for masseter and temporalis muscles

Abstract Introduction The aim of this study was to propose a method of electrodes positioning on the superficial masseter and anterior temporalis muscles for surface electromyographic (sEMG) recordings in order to overcome some known methodological constraints. Methods Fifteen volunteers with normal occlusion participated in two experimental sessions within a 7 day-period. Surface electrodes were placed on two different locations that were based on palpable and individual anatomical references. Surface EMG signals (2000 Hz per channel; A/D: 16 bits; gain: 2000 X; band-pass filter: 20-500 Hz) were recorded under three conditions: mandibular rest position, 30% and 100% of maximum voluntary bite force. Three measurements of maximal bite force were taken by using a force transducer positioned over the lower right first molar region and the highest record was taken into account. The root mean square value was considered for analysis. Intraclass correlation coefficients (ICCs), paired t test, and the Bland-Altman method comprised the statistical analyses. The level of significance was set at 0.05. Results ICC records for right and left masseter and anterior temporalis muscles at T0 (first sEMG record) and T7 (second sEMG record) intervals were significantly different (p<0.05). The results showed satisfactory to excellent reproducibility of RMS values at rest, MVBF and 30% MVBF, as well as for MVBF in kgf. Conclusion The results showed reliable reproducibility for the sEMG signal recording in masseter and anterior temporalis muscles from the protocols presented and under the three conditions investigated.

Evaluation of central vestibular syndrome in dogs using brainstem auditory evoked responses recorded with surface electrodes / Avaliação da síndrome vestibular central em cães usando respostas evocadas auditivas do tronco cerebral gravadas com eletrodos de superfície

The present study aimed to analyse the wave morphology, amplitude, latency, and intervals of the brainstem auditory evoked responses (BAERs) in dogs with central vestibular syndrome (CVS) recorded with surface electrodes. Ten dogs with CVS were examined by mono- and binaural stimulation, using the Neuropack electrodiagnostic system, with stimulus intensities of 90 dBSPL. BAERs examinations revealed morphological changes of waves I, II, III, and V and decreased amplitudes of all waves in 7/10 dogs. P values obtained were = 0.014 for wave I amplitude, 0.031 for II, and III and 0.032 for V. Comparing the latencies of waves I, II, III, and V generated by right and left monoaural stimulation in dogs with CVS, we did not observe significant differences (P > 0.05). No statistical differences were observed for BAERs latencies of the waves recorded after binaural and monaural stimulation (left or right). As far as we know, this is the first study of BAERs using surface electrodes, obtained from dogs with CVS.(AU)

Este estudo destina-se à análise da morfologia, da amplitude, da latência e do intervalo das ondas das respostas evocadas auditivas no tronco cerebral (BAERs) em cães com síndrome vestibular central (CVS) registrados com eletrodos de superfície. Dez cães com CVS foram examinados por estimulação mono e binaural usando um sistema de eletrodiagnóstico Neuropack, com intensidade do estímulo de 90 dBSPL. Os exames BAERs relevaram alterações morfológicas das ondas I, II, III e V, bem como baixas amplitudes para todas as ondas no caso dos 7/10 cães. Os valores de P obtidos foram = 0.014 para ampitude da onda I, 0.031 para a II e 0.032 para a V. Compararam-se as latências das ondas I, II, III e V geradas pelo estímulo monoaural direito e esquerdo em cães com CVS e não foram constatadas diferenças significativas (P > 0.05). Igualmente não foram observadas diferenças estatísticas no caso das latências BAERs no que diz respeito às ondas gravadas depois de estímulos binaural e monoaural (esquerdo ou direito). Pelo que é de conhecimento dos autores da presente pesquisa, este é o primeiro estudo sobre BAERs usando eletrodos de superfície obtidos em cães com CVS.(AU)

Brainstem auditory evoked responses in healthy Argentine Mastiff dogs recorded with surface electrodes / Evocado auditivo de respostas em cães Mastiff argentino saudáveis rever utilizando eletrodos de superfície

Evocado auditivo de respostas ­ BAER ) foi gravado utilizando eletrodos de superfície em sete cães Mastiff argentino saudáveis para estimulações monoaural e binaural em intensidades sonoras de 90 dB NPS . As latências e amplitudes das ondas I, III e V bem como os intervalos InterWave I- III , III -V e IV foram calculados. As diferenças estatísticas foram obtidas para as ondas III e latências V, amplitudes das ondas III e intervalos I- III e I-V entre mono e estimulação binaural. Por serem uma das raças geneticamente predispostas à surdez congênita, obtendo valores de referência BAER, os cães Mastiff argentino têm uma importância clínica especial.(AU)

An electrophysiological study of Riche-Cannieu anastomosis / 中华物理医学与康复杂志

Objective To explore the optimal electrophysiologieal approach for detecting Riehe-Cannieu anastomosis(RCA),an anomalous anastomosis between the deep branch of ulnar nerve and the recurrent branch of the medial nerve in the palm of the hand,and to estimate its incidence. Methods One hundred subjects(56 male,44 female,mean age 37.8 years)without any hand motor or sensory dysfunction were selected randomly.The ulnar nerve was stimulated at both the elbow and wrist,and recordings were made from the abductor pollicis brevis,which is normally innervated by the medial nerve,to document any compound muscle action potentials(CMAP).CMAP recorded from both points during stimulation is an accepted indicator of RCA.Group A comprised 40 hands of 20 subjects,while group B included 160 hands of 80 subjects.Surface electrode stimulation was used in both groups.Surface and needle electrode recording was used in group A,while only needle electrode recording was used in group B.Results In group A,31 hands of 16 subjects were found to have RCA by means of surface electrode recording,but only 6 hands of 3 subjects were found to have RCA by means of concentric needle electrode recording.There was a difference of up t0 80.6% between results obtained by the 2 recording methods.In group B,35 hands of 20 subjects were found to have RCA.A total of 41 hands of 23 subjects among the 100 were found to have RCA when concentric needle electrode recording was used(20.5%incidence). Conclusion The type of recording electrode influences the accuracy of RCA examination.An accurate and reliable result can be obtained by using a concentric needle electrode.The abductor pollicis brevis can be anomalously innervated by the ulnar nerve because of RCA.When both the medial and ulnar nerve have been injured.RCA might result in anomalous clinical symptoms and electrophysiological findings.Thoroughly understanding this anomaly is of crucial importance in the clinical evaluation and diagnosis of medial or ulnar nerve injury,as well as to avoid mistakenly interpreting the electrophysiological data when Riche-Cannieu anastomosis is present.