Motor Point Research Articles

P33-12 Projection of muscle afferents to the sensorimotor cortex after voluntary movement and electrical stimulation of a motor point – An MEG study

P33-12 Projection of muscle afferents to the sensorimotor cortex after voluntary movement and electrical stimulation of a motor point – An MEG study

Low-frequency electrical stimulation can improve ability in the activities of daily living soon after stroke

Objective To assess the efficacy of low-frequency electrical stimulation (LES) in improving ability in the activities of daily living (ADL) of subjects after a recent stroke. Methods In a randomized controlled trial, 37 subjects with a first stroke were randomly divided into an electrical stimulation (ES) group and a control group. In the ES group (n = 19 ) electrodes were applied on the motor points of the tibialis anterior, the peroneal longus and the peroneus brevis muscles. Stimulation current was applied at an intensity set to cause full ankle extension. The stimulus pulse was a symmetric biphasic wave with frequency of 30 Hz, a pulse width of 200 μs, a duty cycle of 5 s on and 5 s off ramped up and down for 1 s each and amplitude up to 90 mA. The current amplitude was adjusted according to each subject's comfort. Stimulation lasted for 30 min/d, 5 d/week for 3 weeks. All subjects in the 2 groups also received a standard rehabilitation program. Evaluations included the Fugl-Meyer motor assessment (FMA) for the lower extremity and the modified Barthel index (MBI) for ADL ability. Measurements were recorded before treatment and after 2 and 3 weeks of treatment. Results Before treatment there was no significant difference between the two groups in terms of age, time post-stroke, stroke severity or the baseline measurements. After 2 and 3 weeks of treatment, the FMA scores in the ES group were significantly higher than those of the control group. The MBI scores in the ES group were also significantly higher than in the control group. The average MBI transferring, walking and stair climbing scores in the ES group were all significantly higher than those in the control group after either 2 or 3 weeks. Conclusion Three weeks of LES can improve ADL ability soon after stroke. Key words: Low-frequency electrical stimulation; Stroke; Activities of daily living

Determination of muscle fatigue index for strength training in patients with Duchenne dystrophy

INTRODUCTION: Muscle weakness is the most prominent impairment in Duchenne muscular dystrophy (DMD) and often involves the loss of functional ability as well as other limitations related to daily living. Thus, there is a need to maintain muscle strength in large muscle groups, such as the femoral quadriceps, which is responsible for diverse functional abilities. However, the load and duration of training for such rehabilitation has proven to be a great unknown, mainly due to the undesired appearance of muscle fatigue, which is a severe factor for the injury of muscle fibers. OBJECTIVES: The aim of the present study was to determine a fatigue index by means of surface electromyography (EMG) for the parameterization of muscle strengthening physiotherapy training. METHODS: A cross-sectional study (case series) was carried out involving four patients with DMD. Three pairs of surface electrodes were placed on the motor point of the Rectus femoris, Vastus lateralis and Vastus medialis of the dominant limb, maintaining the knee at 60º of flexion. The participants were instructed to perform the extension movement of this joint at four strength levels (100%, 80%, 60% and 40% of maximal voluntary isometric contraction). RESULTS: The slope of the linear regression line was used for the determination of the fatigue index, performed by Pearson's test on the median frequency of each strength level. CONCLUSION: Electromyographic measurements of the strength index for muscle training proved to be a simple accessible assessment method, as well as an extremely valuable tool, allowing the design of a muscle strength training program with an individualized load threshold.

Multicenter analysis of diaphragm pacing in tetraplegics with cardiac pacemakers: Positive implications for ventilator weaning in intensive care units

Diaphragm pacing (DP) can replace mechanical ventilation in tetraplegics and in trials has assisted respiration in amyotrophic lateral sclerosis patients. This report describes results of DP in patients with cardiac pacemakers. Prospective, single-center and multicenter, nonrandomized, controlled, interventional protocols under U.S. Food and Drug Administration and/or institutional review board approval were evaluated. Patients underwent laparoscopic diaphragm motor point mapping to identify optimal electrode site for implantation. With diaphragm conditioning, patients were weaned from their ventilator. Perioperative and long-term assessments between the cardiac pacemakers and DP were analyzed for any device-to-device interactions. Over 300 subjects were implanted from 2000 to 2010. Twenty tetraplegics with cardiac pacemakers and DP were analyzed from 6 sites. Subjects ranged from 19 to 61 years old with DP implantation 6 months to 24 years postinjury. There were no immediate or long-term device to device interactions. All patients achieved diaphragm-paced tidal volumes exceeding their basal requirements and, after conditioning, all patients could go >4 hours without mechanical ventilators; 71% could go 24 hours continuously. DP can be safely implanted in tetraplegics having cardiac pacemakers. Applications for temporary use of DP to maintain diaphragm type 1 muscle fiber and improve posterior lobe ventilation may benefit complex critical care patients.

Extent of spontaneous motor recovery after traumatic cervical sensorimotor complete spinal cord injury

Retrospective, longitudinal analysis of motor recovery data from individuals with cervical (C4-C7) sensorimotor complete spinal cord injury (SCI) according to the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI). To analyze the extent and patterns of spontaneous motor recovery over the first year after traumatic cervical sensorimotor complete SCI. Datasets from the European multicenter study about SCI (EMSCI) and the Sygen randomized clinical trial were examined for conversion of American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade, change in upper extremity motor score (UEMS) or motor level, as well as relationships between these measures. There were no overall differences between the EMSCI and Sygen datasets in motor recovery patterns. After 1 year, up to 70% of subjects spontaneously recovered at least one motor level, but only 30% recovered two or more motor levels, with lesser values at intermediate time points. AIS grade conversion did not significantly influence motor level changes. At 1 year, the average spontaneous improvement in bilateral UEMS was 10-11 motor points. There was only moderate relationship between a change in UEMS and a change in cervical motor level (r(2)=0.30, P<0.05). Regardless of initial cervical motor level, most individuals recover a similar number of motor points or motor levels. Careful tracking of cervical motor recovery outcomes may provide the necessary sensitivity and accuracy to reliably detect a subtle, but meaningful treatment effect after sensorimotor complete cervical SCI. The distribution of the UEMS change may be more important functionally than the total UEMS recovered.

Danes with brains

What is it that forces someone performing a maximal effort to slow his pace or to stop? In a recent issue of The Journal of PhysiologyRasmussen et al. (2010) report results that enlighten somewhat the still poorly understood mechanisms underlying the limits of exercise performance. For about a century exercise physiology has mostly concentrated on muscle, cardio-vascular or pulmonary physiology and still today some maintain that the limits of performance are in one or the other. But what happens when one engages in a maximal physical effort, for instance pedalling on a cycle ergometer until exhaustion? At some stage one cannot keep up the intensity of the effort and one has to a stop the effort or at least decrease its intensity. At that moment it may well be that some system (e.g. cardiac output/oxygen transport) is so heavily taxed that its capacity is being reached. But it is the brain which commands the reduction of the intensity or the end of the effort. Physical effort is the result of recruitment of motor units by the brain and the end of effort is the result of their de-recruitment (Kayser, 2003). What remains elusive is how the brain is led to de-recruit motor units at exhaustion. Rasmussen et al. (2010) have in typical Danish style (i.e. methodologically strong and rather invasive) set out to investigate whether at maximum exercise performance in normoxic and/or hypoxic conditions increased brain metabolic activity may perhaps outstrip oxygen delivery leading to a reduction in motor command. To this end they measured arterial–venous differences of blood gases, glucose and lactate over the brain, by inserting blood sampling lines high into the right internal jugular vein and a brachial artery. Brain blood flow was estimated from Doppler measured velocity in the middle cerebral artery. They asked subjects to cycle for 20 min at a moderate load in normoxia followed, after 10 min rest, by 20 min at the same load in hypoxia (= 0.1), a load chosen at the limit of what could be maintained in hypoxia. After a rest the subjects then did a maximum performance test in normoxia. The brain's ability to fully recruit muscle was evaluated by asking the subjects to perform maximum voluntary contractions of the biceps brachii while superimposing electrical stimulation of the motor points or magnetic stimulation over the motor cortex. The authors found that both in hypoxia and during maximum exercise in normoxia the ability of the brain to recruit additional (non-fatigued) muscle (biceps brachii) was compromised, indicated by a 10% decrease in voluntary activation level as quantified with the superimposed stimulation technique. This was accompanied by a 20% reduction in brain oxygen delivery despite an increase in middle cerebral artery blood velocity. Using estimated tissue oxygen tension () they found correlations with the rate of perceived exertion (Borg scale) and voluntary activation levels. Since acute restoration of oxygen supply is known to reverse the advent of exhaustion of exercise in hypoxia (Kayser et al. 1994; Amann et al. 2007; Subudhi et al. 2008), it thus seems plausible to expect a causal link between brain oxygen supply and locomotor muscle recruitment. Using a-v differences that reflect overall effects, Rasmussen et al. (2010) have approached the brain as whole. But it can be expected that during heavy exercise certain groups of neurons are particularly active and may be exposed to more extreme metabolic conditions. The challenge for future work lies in getting a better view of what happens in certain regions of the brain. Motion artefacts during whole body exercise like cycling still pose enormous problems, but the advent of increasingly sophisticated brain imaging techniques are likely to allow a better insight into what happens in the brain at the moment of exhaustion from intense effort. Some groups are starting to work with multisite brain tissue saturation measurements using near infrared spectroscopy, other groups experiment with EEG. Rasmussen et al. (2010) are from the famous ‘Danish school’, a formidable heritage from the early days of August Krogh and the more recent Copenhagen Muscle Research Centre set up by Bengt Saltin. I expect those Danish brains to come up soon with more good ideas to bring us closer to an understanding of what happens in the brain leading it to decrease muscle recruitment at the point of exhaustion.

Innervation zones of the upper and lower limb muscles estimated by using multichannel surface EMG.

The distribution of innervation zones was investigated in 3 subjects for 17 muscles and 8 muscle groups in the upper and lower limb, by detecting bi-directional propagation of motor unit action potentials (MUAPs) with the multichannel surface electrode array. Clarification of the distribution of innervation zones depended on the ease in detecting the propagation of MUAPs and the actual scattering of innervation zones, which were closely related with muscle morphology with respect to the arrangements of muscle fibers. In muscles having fibers running parallel to each other, such as the biceps brachii, intrinsic hand muscles, vastus lateralis and medialis, tensor fasciae latae, peronei, soleus, tibialis anterior, and hypothenar muscles in the foot, it was relatively easy to detect the propagating MUAPs, and the innervation zones were distributed in a relatively narrow band around muscle belly. On the other hand, in muscles with a complicated structure including pinnation of muscle fibers, in-series muscle fibers and aponeurotic tissues, such as the deltoid, flexors and extensors in the forearm, rectus femoris, sartorius, hamstrings and gastrocnemius, it was more difficult to detect the propagating MUAPs and to identify the innervation zones, which were widely scattered or distributed in complex configurations. The distribution of the innervation zones clarified in the present study can be used to find the optimal location of electrodes in surface EMG recordings and of stimulus electrodes in the functional and therapeutic electrical stimulations. It may also be useful in motor point biopsy for diagnosis of neuromuscular diseases as well as in the botulinum toxin injection for the treatment of spasticity.

Anatomic localization of motor entry points and intramuscular nerve endings in the hamstring muscles

To elucidate the location of motor entry points (MEPs) and intramuscular nerve endings of the hamstring muscles. We dissected 50 cadaveric lower extremities to identify the MEPs, where the nerve branch first pierced the muscle belly, and the proximal and distal limit points (PLPs and DLPs, respectively) of the terminal intramuscular nerve endings. These points were measured in relation to a reference line, expressed in x-coordinate, which connected the superior medial aspect of ischial tuberosity to the proximal aspect of the medial femoral epicondyle. We also expressed the MEP in y-coordinate, which is perpendicular to the x-coordinate connecting the superior medial aspect of ischial tuberosity to the lateral aspect of the greater trochanter. Finally, these distances were translated into percentage distances in relation to the total length of the reference lines and their mean values were calculated. For the long head of biceps femoris muscles, the MEPs were located at 41.5 and 36.3% distance of the x and y coordinates, while the PLP and DLP were located at 39.7 and 72.9% distance of the x-coordinate. For the short head, the corresponding data were 56.2, 59.7, 58.9 and 80.2%. The semitendinosus showed two innervations zones; the data for the upper and lower zones were 20.3, 18.9, 18.6, 36.8% and 59.9, 21.4, 56.6, 79.1%, respectively. For the semimembranosus, the data were 62.2, 18.8, 55.9 and 89.1%. The parameters provided from this study should help increase the efficacy and precision of motor point injections to the hamstring muscles.

Diagnostic criteria of traumatic central cord syndrome. Part 1: A systematic review of clinical descriptors and scores

Systematic review. The applied definition of traumatic central cord syndrome (TCCS) lacks specific quantified diagnostic criteria. To review currently applied TCCS diagnostic criteria and quantitative data regarding the 'disproportionate weakness' between the upper and lower extremities described in original studies reporting on TCCS subjects. A MEDLINE (1966 to 2008) literature search was conducted. The descriptors applied to define TCCS were extracted from all included articles. We included original studies that reported on the differences in motor score (based on the Medical Research Council scale) between the total upper extremity motor score (UEMS) and the total lower extremity motor score (LEMS), in a minimum of five TCCS patients at the time of hospital admission. The mean difference between the total UEMS and the total LEMS of the patients included in each study was calculated. Case reports were excluded. None of the identified studies on TCCS patients reported inclusion and/or exclusion criteria using a quantified difference between the UEMS and LEMS. Out of 30 retrieved studies, we identified seven different clinical descriptors that have been applied as TCCS diagnostic criteria. Nine studies reporting on a total of 312 TCCS patients were eligible for analysis. The mean total UEMS was 10.5 motor points lower than the mean total LEMS. There is no consensus on the diagnostic criteria for TCCS. Nevertheless, this review revealed an average of 10 motor points between the UEMS and LEMS as a possible TCCS diagnostic criterion. However, further discussion by an expert panel will be required to establish definitive diagnostic criteria.

J1602-1-1 指・手首運動筋のFES運動点探索装置の開発([J1602-1]機械の知能化と脳工学応用)

There are motor point maps as index of stimulation points to move each muscle for functional electrical stimulation (FES). However we'll usually have to search detailed motor points by trial and error when arranging electrodes since individual differences are large. In this research, we developed a system aids searching motor points of fingers and wrist muscles. It contains 12 × 10 electrodes which cover a forearm and sensors which catch movement of each finger and wrist. It chooses a pair of electrodes in order and stimulates a subject. When the response was measured, it records the response movement and the position of electrode pair. As a result, we obtained the generated motor point map.

Shape and innervation of popliteus muscle

The aim of this study was to delineate the shape of the popliteus muscle and determine the correct motor point site for treating spasticity. A total of 22 legs from 13 fresh Korean cadavers were evaluated. The x-axis was set as a transverse line across the lateral and medial epicondyle of the femur and the y-axis as a vertical line at the midpoint of the medial malleolus of the tibia and lateral malleolus of the fibula. The popliteus muscle is an obtuse triangle in shape. Superior, medial, and inferior angles were 27.2±4.3°, 114.8±19.8°, and 38.0±18.8° respectively. The lengths of the superior, medial, and lateral sides of the triangle were 7.6±1.0 cm, 6.2±1.0 cm, and 11.9±1.5 cm respectively. Nerve branches ran superficially on the periosteum of the tibia and entered the popliteus on its superficial surface. The diverging point of the nerve branch entered the popliteus from the tibial nerve located at the midline of the popliteal fossa and 17% of the leg length above the intercondylar line. Most nerve entry points (83.3%) were within a 2.0×3.0 cm rectangle with the center located at -1.0 cm (-7%) on the x-axis and -3.3 cm (-9%) on the y-axis.

Effect of electrical stimulation on blood glucose level and lipid profile of sedentary type 2 diabetic patients

Background: Physical exercise has emerged as a major tool in the prevention and management of diabetes mellitus, but a large diabetic population is not physically fit for regular exercise programme due to associated complications of diabetes and old age. This unique study is an attempt to explore the use of electrical stimulation as a method of treatment of type 2 diabetic patients. Aims: This study was designed to analyze the effects of electrical stimulation on blood glucose level, lipid profile, and physiological parameters of sedentary type 2 diabetic patients. Settings: This study was experimental in nature with different subject design. Materials and Methods: The experimental group (N = 20) underwent electrical stimulation through surface electrodes placed over motor points of quadriceps femoris muscles for 40 min/day, 3 days/week continued for 2 weeks. Twenty diabetic subjects who received placebo treatment served as the control group. Physiological parameters were measured, and blood samples taken both before and after treatment on the first day and the last day of the intervention in both groups. Statistical Analysis: Related and unrelated t-tests were used for statistical analysis. Results and Conclusion: The percentage change in blood glucose level scores of the experimental group (12.71%) was much higher as compared to the control group (4.06%) after a single session of treatment. Following 2 weeks of electrical stimulation, the blood glucose level was significantly (t = 5.026, P = 0.001) reduced in experimental group, but there was an insignificant fall in the same for the control group. Our results suggest that electrical stimulation can be used to assist in the control of blood glucose level in type 2 diabetic patients.

Fluoxetine Blocks Myotonic Runs and Reverts Abnormal Surface Electromyogram Pattern in Patients With Myotonic Dystrophy Type 1

To verify the effects of a muscular injection of fluoxetine both on needle electromyogram (EMG) "myotonic runs" and on the surface EMG pattern in patients affected by myotonic dystrophy type 1. Needle EMG recording: We performed needle EMG recordings on the tibialis anterior or opponent thumb muscle in 3 patients. The resting electrical activity and the myotonic discharge were detected before and after the local injection of 100 microL of fluoxetine. Surface EMG recording: A motor point stimulation protocol was carried out on the tibialis anterior of 3 patients. Stimulation consisted of 10-second, 15-Hz pulse train, 0.1 ms in duration. A supramaximal stimulation was applied, and the surface myoelectric signal was recorded. The averaged rectified value (ARV) of the amplitude was evaluated before and after the intramuscular injection of 300 microL of fluoxetine. Needle EMG: The injection of fluoxetine induced a clear-cut reduction of the basal electrical activity and made it impossible to evoke "myotonic runs" in all the patients tested. The reversibility of the effect of the drug was checked in 2 patients who exhibited a partial recovery of myotonic EMG activity 40 minutes after the administration. Surface EMG: The patients showed the typical decreasing ARV pattern before the drug administration; the fluoxetine injection consistently provoked a clear and complete recovery of the normal increasing ARV curve. We showed, for the first time, that the local application of fluoxetine produces functional modifications in myotonic dystrophy type 1 muscle electrical properties. The relevance of this study consists in the introduction of fluoxetine, a well-known and largely used drug, as a tool for investigating further therapeutical approaches in this disease.

Safety of Eptifibatide for Subcortical Stroke Progression

Background: There is no proven treatment for stroke progression in patients with subcortical infarcts. Eptifibatide, a glycoprotein IIb/IIIa inhibitor, might halt stroke progression by improving flow in the microcirculation. Methods: We conducted a retrospective analysis of patients with subcortical stroke who experienced deterioration and were treated with eptifibatide (loading dose 180 μg/kg; infusion 2 μg/kg/min) for 24–48 h. Oral antiplatelet agents were started 6 h before discontinuation of eptifibatide. Results: Twenty-four patients with subcortical strokes were treated. The median admission NIHSS score was 5.0, which worsened to 8.5 (motor 5.0) before starting eptifibatide. The median NIHSS score 24 h after starting eptifibatide was 5.5. At 24 h, 42% had motor NIHSS scores less than or equal to pre-deterioration scores (50% for total NIHSS), and 50% had improved at least 1 motor point compared to pre-eptifibatide scores, which was sustained until hospital discharge. At discharge, the median total NIHSS score was 4.5. Ninety-two percent of patients were discharged home or to inpatient rehabilitation. Treatment was stopped early in 1 case due to a platelet drop <100,000/μl. No systemic or intracerebral bleeding occurred. Conclusions: Eptifibatide infusion may be safe in patients with subcortical ischemic strokes. Future studies are needed to test the safety and potential efficacy of this agent in subcortical stroke progression.

Elicitability of muscle cramps in different leg and foot muscles

To explore the efficacy of muscle motor point stimulation in eliciting muscle cramps, 11 subjects underwent eight sessions of electrical stimulation of the following muscles bilaterally: abductor hallucis flexor hallucis brevis, and both heads of the gastrocnemius muscles. Bursts of 150 square wave stimuli (duration: 152 micros; current intensity: 30% supramaximal) were applied. The stimulation frequency was increased from 4 pulses per second (pps) at increments of 2 pps until a cramp was induced. The number of cramps that could be elicited was smaller in flexor hallucis brevis than in abductor hallucis (16 vs. 22 out of 22 trials each; P < 0.05) and in the lateral gastrocnemius than in the medial gastrocnemius (5 vs. 20 out of 22 trials each; P < 0.0001). We show that leg and foot muscles have different cramp susceptibility, and the intermuscle variability in the elicitability profile for electrically induced cramps supports the use of the proposed method for cramp research.

Avaliação do ácido lático em indivíduos com hemiparesia pós-acidente vascular encefálico após estimulação elétrica para fortalecimento muscular

O fortalecimento da musculatura parética promove melhora da capacidade funcional, o que pode ser obtido pela estimulação elétrica funcional (EEF), porém são necessários parâmetros específicos para evitar fadiga muscular. Este estudo visou verificar, em indivíduos com hemiparesia pós-AVE, o tempo de repouso (time off) necessário para reabsorção do ácido lático durante a EEF, de modo a evitar a fadiga - detectada por lactacidemia (concentração excessiva de ácido lático). Foram coletadas amostras de sangue de 18 indivíduos portadores de hemiparesia em sete momentos, antes, durante e após a EEF. A corrente quadrada bifásica, de 50 Hz, foi usada com time on de 10 segundos (s) e o time off variou de 10 s (protocolo 1) a 30 s (protocolo 2), sobre o ponto motor do músculo tibial anterior. Na análise do sangue coletado, não foi encontrada diferença estatisticamente significante (p&gt;0,05) entre os dois protocolos; tampouco foi registrada diferença no período imediatamente pós-terapia. Pode-se pois afirmar que a ferramenta utilizada para mensurar lactacidemia não se mostrou eficaz na detecção da fadiga muscular, inviabilizando verificar o tempo ideal de repouso (time off), sendo necessários mais estudos em busca de protocolos seguros. Sugere-se a continuidade deste estudo, com alteração do músculo e atividade funcional eliciada pela estimulação elétrica, bem como uma ferramenta alternativa na mensuração e detecção da fadiga muscular.

Anatomic Localization of Motor Points of Hip Adductors

To identify the precise location of the motor points of hip adductors in relation to bony landmarks. Nineteen limbs from ten adult cadavers were anatomically dissected. The motor point of each adductor muscle was determined by measuring its distance from the pubic tubercle with reference to a line joining the pubic tubercle and the medial epicondyle of the femur, and this distance was expressed as a percentage. For describing the mediolateral relationship between the motor point of each adductor and bony landmarks, its distance from the pubic tubercle was measured with reference to a line joining the pubic tubercle and the greater trochanter of the femur, and the result was expressed as a percentage. The percent distances along the longitudinal reference line distal to the pubic tubercle were as follows: adductor longus, 26.0% +/- 4.8%; adductor brevis, 21.0% +/- 4.8%; gracilis, 32.1% +/- 2.1%; and adductor magnus, 30.4% +/- 4.1%. Further, the percent distances along the horizontal reference line lateral to the pubic tubercle were as follows: adductor longus, 24.9% +/- 7.8%; adductor brevis, 24.9% +/- 7.4%; and adductor magnus, 33.6% +/- 5.9%. Identification of these motor points facilitates the efficacy and efficiency of a neural blockade and decreases undesirable complications.

A method for better positioning bipolar electrodes for lower limb EMG recordings during dynamic contractions

To obtain a high quality EMG acquisition, the signal must be recorded as far away as possible from muscle innervations and tendon zones, which are known to shift during dynamic contractions. This study describes a methodology, using commercial bipolar electrodes, to identify better electrode positions for superficial EMG of lower limb muscles during dynamic contractions. Eight female volunteers participated in this study. Myoelectric signals of the vastus lateralis, gastrocnemius medialis, peroneus longus and tibialis anterior muscles were acquired during maximum isometric contractions using bipolar electrodes. The electrode positions of each muscle were selected assessing SENIAM and then, other positions were located along the length of muscle up and down the SENIAM site. The raw signal (density), the linear envelopes, the RMS value, the motor point site, the position of the IZ and its shift during dynamic contractions were taken into account to select and compare electrode positions. For vastus lateralis and peroneus longus, the best sites were 66% and 25% of muscle length, respectively (similar to SENIAM location). The position of the tibialis anterior electrodes presented the best signal at 47.5% of its length (different from SENIAM location). The position of the gastrocnemius medialis electrodes was at 38% of its length and SENIAM does not specify a precise location for signal acquisition. The proposed method should be considered as another methodological step in every EMG study to guarantee the quality of the signal and subsequent human movement interpretations.

The Validity and Reliability of the Motor Point Detection System: A Preliminary Investigation of Motor Points of the Triceps Surae Muscles

Lee NG, You JH, Park HD, Myoung HS, Lee SE, Hwang JH, Kim HS, Kim SS, Lee KJ. The validity and reliability of the motor point detection system: a preliminary investigation of motor points of the triceps surae muscles. Objective To investigate the validity and reliability of the motor point detection system in cadavers and healthy young adults. Design Correlation statistics. Setting University research laboratory. Participants Sixty-two lower limbs of 31 healthy young adults (mean age, 22.3±1.8) and 10 size-matched lower limbs from cadavers were used. Interventions Not applicable. Main Outcome Measures The validity of the motor point detection system's motor point measure was determined by comparing the motor point locations of the lower-leg muscles obtained from the motor point detection system with the established anatomic motor point locations from our previous cadaveric dissection study. The anatomic motor points were determined by tracing the terminal motor nerve branches on soleus, medial, and lateral gastrocnemius muscles through the dissection of adult cadavers. The test-retest reliability was determined by repeatedly measuring the locations of motor points in healthy young adults on 2 separate occasions, approximately 24 hours apart. The intraclass correlation coefficient (ICC) was computed to determine correlation, and an independent t test was used to determine the difference between the demographic and clinical variables at the significance level ( P<.05). Results Correlation analysis revealed relatively high validity between the motor point detection system and cadaver-dissected motor point location measurements (ICC 2,1=.71–.92, P<.05). The test-retest reliability showed excellent correlation between the repeated measures (range, ICC 1,2=.90–.95 at P<.05). Conclusions Our results showed that the motor point detection system was accurate and consistent in the measurement of motor point locations of the lower-leg muscles. This system can be considered as an alternative device to localize motor points in clinical settings. Our motor point detection system warrants further investigation in pathologic population.

Complete worldwide operative experience in laparoscopic diaphragm pacing: results and differences in spinal cord injured patients and amyotrophic lateral sclerosis patients

Diaphragm movement is essential for adequate ventilation, and when the diaphragm is adversely affected patients face lifelong positive-pressure mechanical ventilation or death. This report summarizes the complete worldwide multicenter experience with diaphragm pacing stimulation (DPS) to maintain and provide diaphragm function in ventilator-dependent spinal cord injury (SCI) patients and respiratory-compromised patients with amyotrophic lateral sclerosis (ALS). It will highlight the surgical experiences and the differences in diaphragm function in these two groups of patients. In prospective Food and Drug Administration (FDA) trials, patients underwent laparoscopic diaphragm motor point mapping with intramuscular electrode implantation. Stimulation of the electrodes ensued to condition and strengthen the diaphragm. From March of 2000 to September of 2007, a total of 88 patients (50 SCI and 38 ALS) were implanted with DPS at five sites. Patient age ranged from 18 to 74 years. Time from SCI to implantation ranged from 3 months to 27 years. In 87 patients the diaphragm motor point was mapped with successful implantation of electrodes with the only failure the second SCI patient who had a false-positive phrenic nerve study. Patients with ALS had much weaker diaphragms identified surgically, requiring trains of stimulation during mapping to identify the motor point at times. There was no perioperative mortality even in ALS patients with forced vital capacity (FVC) below 50% predicted. There was no cardiac involvement from diaphragm pacing even when analyzed in ten patients who had pre-existing cardiac pacemakers. No infections occurred even with simultaneous gastrostomy tube placements for ALS patients. In the SCI patients 96% were able to use DPS to provide ventilation replacing their mechanical ventilators and in the ALS studies patients have been able to delay the need for mechanical ventilation up to 24 months. This multicenter experience has shown that laparoscopic diaphragm motor point mapping, electrode implantation, and pacing can be safely performed both in SCI and in ALS. In SCI patients it allows freedom from ventilator and in ALS patients it delays the need for ventilators, increasing survival.