Motor Conduction Time Research Articles

The Impact of Robotic Rehabilitation on the Motor System in Neurological Diseases. A Multimodal Neurophysiological Approach.

Motor disability is a key feature of many neurological diseases, influencing the social roles of affected patients and their ability to perform daily life activities. Current rehabilitation capacities are overwhelmed by the age-related increase of motor dysfunctions seen, for example, in stroke, extrapyramidal or neuromuscular diseases. As the patient to rehabilitation personnel ration increases, robotic solutions might establish the possibility to rapidly satisfy the increasing demand for rehabilitation. This paper presents an inaugural exploratory study which investigates the interchangeability of a novel experimental robotic rehabilitation device system with classical physical therapy, using a multimodal neurophysiological assessment of the motor system—quantitative electroencephalogram (EEG), motor conduction times and turn/amplitude analysis. Preliminary results show no significant difference between the two methods; however, a significant effect of the therapy was found on different pathologies (beneficial for vascular and extrapyramidal, or limited, and only on preventing reduction of joint movements in neuromuscular).

Motor Conduction Time Along the Cauda Equina at Rest and After Walking Following Electrical and Magnetic Stimulation

Introduction: Intermittent neurogenic claudication because of lumbosacral spinal stenosis (LSS) usually begins in people over 60 years. Aim is to measure motor conduction time (CT) in the cauda equina (CE) in healthy people and patients with intermittent neurogenic claudication because of LSS at rest and after walking. To compare magnetic and electrical stimulation (MS and ES), and the sensitivity and specificity of both methods. Methods: Study was randomized controlled trial. Motor CT in the CE of healthy people and patients with intermittent neurogenic claudication due to LSS at rest and after walking as well as the sensitivity and specificity of both methods were calculated. Results: In healthy subjects, there were no statistically significant changes in CECT after ES (2.9 ms ± 1.6 ms) and MS (3.4 ms ± 1.3 ms) at rest, but it was statistically significantly longer in patients with LSS (5.2 ms ± 1.2 ms) after a 10-minute walk. The best sensitivity and specificity were after MS of CE after a 10-minute walk. Conclusions: We noted statistically significantly prolonged CECT in patients with intermittent neurogenic claudication due to LSS after walking compared to being at rest and compared to healthy participants. We got the best sensitivity and specificity after MS of the CE after a 10-minute walk. Measuring CECT could become a useful routine non-invasive method, which could help physicians to choose an optimal way of treatment for people with intermittent neurogenic claudication because of LSS. However, the number of participants was small, and it would be advisable to conduct a study with a larger number of participants.

A patient with McLeod syndrome showing involvement of the central sensorimotor tracts for the legs

BackgroundMcLeod syndrome is a rare X-linked recessive acanthocytosis associated with neurological manifestations including progressive chorea, cognitive impairment, psychiatric disturbances, seizures, and sensorimotor axonal polyneuropathy. However, no studies have investigated the functioning of central sensorimotor tracts in patients with McLeod syndrome.Case presentationA 66-year-old man had experienced slowly progressive chorea and gait disturbance due to lower limb muscle weakness since his early fifties. Blood examinations showed erythrocyte acanthocytosis and the reduction of Kell antigens in red blood cells. Brain magnetic resonance imaging showed atrophy of the bilateral caudate nuclei and putamen. The diagnosis of McLeod syndrome was confirmed by the presence of a mutation of the XK gene on the X chromosome. Somatosensory-evoked potential and transcranial magnetic stimulation studies demonstrated that the central sensory and motor conduction times were abnormally prolonged for the lower extremity but normal for the upper extremity.ConclusionsThis is the first report of the involvement of the central sensorimotor tracts for the legs in a patient with McLeod syndrome. The clinical neurophysiological technique revealed the central sensorimotor tracts involvements clinically masked by neuropathy.

F107. Sensory and motor evoked potentials in a multicenter setting: Estimation of detectable group differences at varying sample sizes

Introduction Sensory and motor evoked potentials (SEP; MEP) can be used to measure quantitatively the extent of delayed signal conduction in multiple sclerosis (MS). They may be useful to monitor disease course and even serve as biomarkers in clinical trials (Hardmeier et al., 2017). Here we estimate the detectable differences in group means and in longitudinal group changes for different sample sizes accounting for physiological and rater-related variability. Methods 15 healthy subjects were evaluated twice within 30 days with median and tibial SEP and upper (UL) and lower limb (LL) MEP in three centers 1-3 according to a common standardized protocol in keeping with IFCN recommendations. Four neurophysiologists (FJ, MH, PA, PF) independently marked all curves blinded to their previous ratings using a web-based tool (EPMark; HB, MH, PF). N20, P40, shortest and mean cortico-muscular-latencies (CML) were analyzed; central (motor) conduction times were omitted due to lower test-retest-reliability. In addition, the sum of the z-transformed results from each test was divided by number of tests to yield a quantitative EP-score (qEPS). Mixed effect models using results of time-points 1 and 2 as combined outcomes were employed to calculate the standard error (SE) of a group mean of cross-sectional measurements or longitudinal changes. The respective SE formulas were used to calculate the difference d detectable with a power of 90% [d = (1.96 + 1.28) ∗ sqrt( SE 1 2 + SE 2 2 ) -2CoV] as a function of group size assuming a central reading center. Covariance between group means by common influence of raters on both groups was ignored for a more conservative estimate. Results For a sample size of n = 60, cross-sectional group mean difference (d1) is estimated to range from 0.6 to 2.1 ms (N20: 0.6, P40: 1.5; CML-UL [shortest/ mean]: 1.4/1.2; CML-LL: 1.7/2.1), and longitudinal mean group difference (d2) from 0.4 to 2.7 ms (N20: 0.4, P40: 1.0; CML-UL: 1.1/0.8; CML-LL: 1.6/2.7). For a sample size of n = 100, d1 ranged from 0.5 to 2.0 ms (N20: 0.5, P40: 1.2; CML-UL: 1.1/1.0; CML-LL: 1.4/2.0), and d2 from 0.4 to 2.6 ms (N20: 0.4, P40: 0.8; CML-UL: 0.9/0.7; CML-LL: 1.5/2.6). For qEPS [including shortest or mean CML], d1 was 0.5/0.4 ms for n = 60, and 0.4/0.3 ms for n = 100; d2 was 0.3/0.2 ms for n = 60 and 0.2/0.2 for n = 100. Conclusion Quantitative evaluation of combined SEP and MEP is possible in a multicenter setting with an independent reading center and allows reliable detection of significant differences in small groups of subjects. When evaluating an intervention, significant changes of EP results at an individual level help to identify responders, while significant changes at a group level may help to determine the biological effectiveness of an intervention. However, variability may be higher in patients and thus, consecutively, estimates of sample size. Supported by an unconditional research grant from Biogen Inc. MA, USA, which had no influence in planning the study or data analysis.

Preparation for reaction time tasks in multiple sclerosis

Background Sensorimotor integration can be assessed using simple reaction time tasks to somatosensory stimuli (ssRT). Tasks performed to stimuli applied to the contralateral hemibody would reveal interhemispheric transfer of information (IHT) across corpus callosum, while tasks performed when a startling-auditory stimulus (SAS) is presented together with the somatosensory cue would reveal the level of subcortical motor preparation. We studied both preparation and IHT in MS patients in whom callosal pathways and subcortical structures may be particularly involved. Methods In 13 controls and 20 mildly disabled relapsing-remitting MS patients, we studied ssRT for voluntary wrist-extension to ipsilateral and contralateral low intensity electrical stimuli, applied to the index finger. Percentage delay (PD) of contralateral vs ipsilateral responses was calculated as a measure of IHT. StartReact trials were performed applying randomly a SAS in ssRT trials (20%). Percentage shortening (SAS-Short) with respect to ssRT was calculated as a measure of the effectiveness of preparation. Motor conduction time (MCT) was assessed by recording the motor-evoked potentials to TMS. Results In controls, mean PD of contralateral responses was 105.7% longer than for ipsilateral responses. In StartReact trials, the mean SAS-Short was 29.7% for ipsilateral and 23.3% for contralateral responses. With respect to controls, patients had no differences in PD (105.4%) but showed significantly lower SAS-Short for ipsilateral (23.4%; p = 0.02) and contralateral trials (10.9%; p = 0.005). Contralateral SAS-Short was inversely correlated with MCT (r = −0.294). Two patients had abnormally delayed orbiculari-oculi responses to SAS. Conclusions Patients with MS have defective subcortical motor preparation that is worse when IHT sensorimotor integration is required.

Defective sensorimotor integration in preparation for reaction time tasks in patients with multiple sclerosis.

Slowness of voluntary movements in patients with multiple sclerosis (MS) may be due to various factors, including attentional and cognitive deficits, delays in motor conduction time, and impairment of specific central nervous system circuits. In 13 healthy volunteers and 20 mildly disabled, relapsing-remitting MS patients, we examined simple reaction time (SRT) tasks requiring sensorimotor integration in circuits involving the corpus callosum and the brain stem. A somatosensory stimulus was used as the imperative signal (IS), and subjects were requested to react with either the ipsilateral or the contralateral hand (uncrossed vs. crossed SRT). In 33% of trials, a startling auditory stimulus was presented together with the IS, and the percentage reaction time change with respect to baseline SRT trials was measured (StartReact effect). The difference between crossed and uncrossed SRT, which requires interhemispheric conduction, was significantly larger in patients than in healthy subjects (P = 0.021). The StartReact effect, which involves activation of brain stem motor pathways, was reduced significantly in patients with respect to healthy subjects (uncrossed trials: P = 0.015; crossed trials: P = 0.005). In patients, a barely significant correlation was found between SRT delay and conduction abnormalities in motor and sensory pathways (P = 0.02 and P = 0.04, respectively). The abnormalities found specifically in trials reflecting interhemispheric transfer of information, as well as the evidence for reduced subcortical motor preparation, indicate that a delay in reaction time execution in MS patients cannot be explained solely by conduction slowing in motor and sensory pathways but suggest, instead, defective sensorimotor integration mechanisms in at least the two circuits examined.

Central motor conduction in brachial monomelic amyotrophy

Prevalence of subclinical involvement of motor pathways in clinically diagnosed Brachial Monomelic Amyotrophy (BMMA) is unknown. To determine the prevalence of subclinical involvement of central motor pathways in BMMA using transcranial magnetic stimulation. Prospective case-control study. Central motor conduction time (CMCT) was determined by 'F' wave method using figure-of-eight coil attached to Magstim 200 stimulator, in 17 patients with BMMA. Motor evoked potentials were recorded from first dorsal interosseous of the affected (AFF) and unaffected upper limbs (UNAFF) at rest and during partial contraction. Comparison was made with data from 10 healthy controls (CTRL). Descriptive analysis and Analysis of Variance (ANOVA). Compared to controls, the mean CMCT of AFF was significantly prolonged, both at rest and contraction: (a) Rest: AFF-6.68+/-1.78 ms, UNAFF-6.36+/-1.16 ms, CTRL-5.71+/-1.02 ms; Fisher's PLSD for AFF vs. CTRL: P =0.037, (b) Contraction: AFF-5.78+/-1.62 ms, UAFF - 4.86+/-1.38 ms, CTRL-4.06+/-0.80 ms; Fisher's PLSD for AFF vs. CTRL; P =0.0002, AFF vs. UNAFF- P =0.044). Prolonged CMCT (>mean+2SD of controls) was observed in 29.4% of AFF and 6.25% of UNAFF at rest, and in 47.1% and 23.5% respectively during contraction. Dysfunction of central motor pathways was observed in both affected and unaffected upper limbs of some patients with BMMA of upper limbs. The dysfunction was more pronounced during voluntary contraction. A larger study is needed to validate the significance of these findings.

Mielopatía cervical: análisis retrospectivo de los resultados quirúrgicos de 54 pacientes tratados mediante discectomía y fusión intersomática por vía anterior

Patients and methodsWe perform a retrospective analysis of clinical results in 53 consecutive patients surgically treated for cervical myelopathy or myelo-radiculopathy with anterior cervical discectomy and interbody fusión by means of the Cloward procedure. Results64.2% of the patients had good outcome as measured by the improvement in one or more grades in the Nurick's scale. No mortality related to the surgical procedure was noted, although 9.4% of the cases suffered neurological deterioration. Correct fusión was achieved in 92.5% of the patients, with a rate of post-surgical kyphosis of 9.4%. Multivariate analysis identified as factors related to the clinical outcome: age (p=0.008), vascular risk factors (p=0.031), duration of symptoms (p=0.002), pre-surgical neurological status (p<0.001), neuroradiological diagnosis (p=0.014), intramedullary high signal intensity changes in T2-weighted images (p=0.008), prolongation of the central somatosensory or motor conduction times (p=0.004) and neurologic complications (p=0.012) ConclusionsTreatment optimisation of the patient suffering cervical spondylotic myelopathy requires individualised evaluation. Prospective randomised studies are needed to answer the questions when and how to opérate.

LATERAL PECTORAL NERVE CONDUCTION

The aim of this study was to measure the motor conduction time (MCT) and velocity of the lateral pectoral nerve (LPN) in normal subjects and patients with neuropathy. For the LPN, we determined that the average MCT was 3.9 m/s using Erb stimulation with needle recording, and the average motor conduction velocity was 70.6 m/s using Erb stimulation and axilla stimulation with needle recordings in normal subjects. In patients, prolonged MCT in LPN was found in 3 of 6 patients with unilateral plexopathy and 3 of 4 patients with polyneuropathy. It was determined that MCT and motor conduction velocity in LPN was as sensitive as biceps brachii MCT in patients with unilateral plexopathy. Furthermore, the motor conduction velocity in the LPN may be beneficial to elucidate the localization of involvement in polyneuropathies, such as distal or proximo-distal

A study of motor dysfunction associated with schizophrenia based on analyses of movement-related cerebral potentials and motor conduction time

Background: Several reports have shown that schizophrenics have motor dysfunction. The aim of this study was to identify the site of the nerve damage responsible for the motor dysfunction in schizophrenics by measuring both movement-related cerebral potentials (MRCPs) and motor conduction times. Methods: The subjects were 27 patients and 31 controls. There was no significant difference in age, nor in the length of the subjects’ arms between the two groups. MRCPs were recorded during voluntary self-paced index movements of the thumb. The motor nerve conduction time was determined by magnetically stimulating the motor cortex and the spinal root. Results: Six of 27 schizophrenics had normal MRCPs, but the remaining 21 showed abnormal MRCPs. Of the 31 controls, 27 were normal, whereas 4 showed abnormal MRCPs. The difference between the two groups was significant; however, no significant differences were found in the motor conduction times, the motor root conduction times, or the central motor conduction times between the two groups. Conclusions: Our results suggest that the responsible focus of motor nerve disorder in schizophrenia lies in the motor-integrating system in frontal lobe, and not in the nervous conduction system from the brain to the muscles.

Electrophysiological features of central motor conduction in spinocerebellar atrophy type 1, type 2, and Machado-Joseph disease

OBJECTIVESTo characterise electrophysiologically the central motor conduction of spinocerebellar atrophy type 1 (SCA1), type 2 (SCA2), and Machado-Joseph disease (MJD).METHODSMotor evoked potentials (MEPs) triggered by transcranial magnetic stimulation (TMS) was...

Transcranial magnetic stimulation as a prognostic tool in stroke

Our aims were to evaluate the prognostic usefulness of magnetic motor evoked potentials (MMEPs) in ischemic stroke, to study the evolution of MMEP abnormalities and the relationships between MMEP abnormalities and infarction topography. We prospectively analyzed 50 consecutive ischemic stroke patients who were followed up to 1 year. MMEPs were recorded 1, 3, 30 and 90 days after stroke and we measured amplitudes and latencies/central motor conduction times (CMCTs) of MMEPs from hypothenar, biceps brachiallis, gastrocnemius and quadriceps. Univariate and multivariate analyses of the clinical and MMEPs data were performed. Patients with Rankin 0–3 at 1 year had had acutely MMEPs with shorter latencies and higher amplitudes than patients with Rankin 4–5 or deceased patients. Increased blood pressure correlated with increased survival, whereas increased heart rate and hyperglycemia correlated with increased mortality. The variables infarction size on second CT, age, and first day CMCT-S1 correctly classified 1 year outcome on discriminant analysis. The inclusion of MMEPs values increased the probability of correct classification from 76% to 84%. We conclude that in patients with nondisabling strokes MMEPs may have an independent value in the prediction of prognosis, increasing the accuracy of prognosis calculations made employing clinical and laboratory data. Topography of lesions should be considered when analyzing MMEP abnormalities after stroke.

P151 Spinal cord signal change (SC) and motor conduction time (MCT) in cervical myelopathy

P151 Spinal cord signal change (SC) and motor conduction time (MCT) in cervical myelopathy

Age and weight effects on motor nerve conduction time measurements in an asymptomatic industrial population

Motor conduction delay has been demonstrated in patients with carpal tunnel syndrome (CTS), however, there is also evidence that conduction slowing can be effected by other factors, e.g., the aging process. Recent development of the digital electroneurometer, a hand-held, battery-powered device for measuring motor nerve conduction time, has made this test available for CTS screening in industry. A cross-sectional study of 77 industrial workers was performed to determine the relationship between median motor nerve conduction time at the carpal tunnel and select personal factors. Motor nerve conduction time increased with age, length of employment, and weight. However, these variables accounted for only 20.3% of the variance in conduction time. The study indicates users of this device should be aware of these effects, and that other sources of variation must be identified and controlled if motor nerve conduction tests are to be used for CTS screening in industry.

Clinical Value of Magnetic Stimulation in Stroke

Magnetic stimulation was performed on 22 patients with acute stroke, Only 1 patient had a prolonged motor conduction time (MCT); this was associated with a poor recovery. In 11 patients, motor evoked

Abnormalities of central motor conduction in Parkinson's disease

The new technique of magnetic stimulation was used to measure amplitude of the motor evoked potential (MEP) recorded from abductor digiti minimi whilst stimulating at the head, and motor conduction time (MCT) between head and neck. Bilateral studies were made in 12 normal subjects and 56 patients with Parkinson's disease. The amplitudes of the MEPs were significantly larger (P less than 0.05) in the patients (mean 1.6 mV, SD 1.4) compared with the normal subjects (mean 0.9 mV, SE 0.6). MCTs were significantly shorter (P less than 0.001) in patients (mean 8.1 ms, SD 1.3) compared with the normal subjects (mean 9.4 ms, SD 1.2). Although the pathophysiological basis of these changes has not been determined, they provide objective measurements which may be clinically valuable in monitoring therapy.

Pre- and postoperative motor conduction times, measured using magnetic stimulation, in patients with cervical spondylosis

Motor conduction time (MCT) between head and neck in pathways to abductor digiti minimi was measured pre- and postoperatively in 15 patients. There was a significant improvement in MCTs in patients with myelopathy who improved clinically, but preoperative MCTs provided no clear, predictive information. Magnetic stimulation may be of value in quantifying motor function before and after surgery in patients with cervical spondylosis.

Motor conduction times, using magnetic cerebral stimulation, vary more in patients with abnormal conduction than with normal conduction in stable definite multiple sclerosis: A.D. Forti, [formula omitted] and J. Adams (Dept. of Clinical Neurophysiology / ARMS Research Unit, Central Middlesex Hospital, London NW10 7NS, U.K.)

Motor conduction times, using magnetic cerebral stimulation, vary more in patients with abnormal conduction than with normal conduction in stable definite multiple sclerosis: A.D. Forti, [formula omitted] and J. Adams (Dept. of Clinical Neurophysiology / ARMS Research Unit, Central Middlesex Hospital, London NW10 7NS, U.K.)

Local neurotoxicity of methylmethacrylate monomer

A technique was devised which allowed a controlled exposure to methylmethacrylate liquid on rat tail skin. The procedure was repeated 3 h daily for 8 weeks. This caused keratolysis without ulcerations in the exposed skin and abnormal muscle responses to stimulation of the rat tail motor nerves by a skin electrode through the treated area after 4 weeks of exposure. The motor conduction time did not differ from controls. The results point to a local neurotoxic reaction by the absorbed methylmethacrylate. This technique may prove valuable in experiments on the determination of dermal and local toxicity of new chemicals.

Carpal tunnel syndrome in pregnancy.

Occurrence of the carpal tunnel syndrome in pregnancy was studied by examining 100 consecutive obstetric admissions. Twenty-one patients reported paresthesias or hypesthesia in the median nerve sensory distribution of the hand during the pregnancy; eight of these had decreased sensation subjectively at the time of examination one to three days after delivery; two had trophic changes, loss of sudomotor function, thenar atrophy, and decreased two-point discrimination; and one had a delay in motor conduction time across the carpal tunnel. Of the 21 patients, 18 became asymptomatic before or shortly after delivery. The remaining three were asymptomatic three months after delivery. We conclude that the incidence of symptoms is probably greater than usually appreciated, but that few patients require treatment. Steroid injection may occassionally be necessary, but the need for surgical intervention is rare.