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

2015 ◽  
Vol 113 (5) ◽  
pp. 1462-1469 ◽  
Author(s):  
Christopher Cabib ◽  
Sara Llufriu ◽  
Jordi Casanova-Molla ◽  
Albert Saiz ◽  
Josep Valls-Solé
Keyword(s):  
Multiple Sclerosis ◽  
Reaction Time ◽  
Brain Stem ◽  
Healthy Subjects ◽  
Sensorimotor Integration ◽  
Motor Preparation ◽  
Conduction Time ◽  
Sensory Pathways ◽  
The Difference ◽  
Startreact Effect

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.

Preparedness for landing after a self-initiated fall

2012 ◽  
Vol 108 (9) ◽  
pp. 2501-2508 ◽  
Author(s):  
Juan M. Castellote ◽  
Ana Queralt ◽  
Josep Valls-Solé
Keyword(s):  
Reaction Time ◽  
Auditory Stimulus ◽  
Healthy Subjects ◽  
Muscle Activation ◽  
Motor Program ◽  
Experimental Conditions ◽  
Imperative Signal ◽  
Precise Information ◽  
Startreact Effect

A startling auditory stimulus (SAS) causes a faster execution of voluntary actions when applied together with the imperative signal in reaction time tasks (the StartReact effect). However, speeding up reaction time may not be the best strategy in all tasks. After a self-initiated fall, the program for landing has to be time-locked to foot contact to avoid damage, and therefore advanced execution of the program would not be convenient. We examined the effects of SAS on the landing motor program in 8 healthy subjects that were requested to let themselves fall from platforms either 50 or 80 cm high at the perception of a visual imperative signal and land on specific targets. In trials at random, SAS was applied either together with the imperative signal (SASIS) or at an appropriate prelanding time (SASPL). As expected, the latency of takeoff was significantly shortened in SASIS trials. On the contrary, the timing of foot contact was not significantly different for SASPL compared with control trials. No changes were observed in the size of the electromyograph bursts in the two experimental conditions with respect to the control condition. Our results indicate that the landing program after a self-initiated fall may in part be organized at the time of takeoff and involve precise information on timing of muscle activation. Once launched, the program is protected against interferences by external inputs.

Electromyographic activity to keep a lower limb in a raised position in healthy subjects and subjects with multiple sclerosis

2008 ◽  
Vol 14 (5) ◽  
pp. 691-693
Author(s):  
R Gatti ◽  
M Corti ◽  
S Govetto ◽  
K Bonzani ◽  
S Boccardi
Keyword(s):  
Multiple Sclerosis ◽  
Supine Position ◽  
Lower Limb ◽  
Healthy Subjects ◽  
Biceps Femoris ◽  
Abdominal Muscles ◽  
Electromyographic Activity ◽  
Hip Kinematics ◽  
The Difference ◽  
The Right

The objective of this work was to assess the activation of the stabilization muscles used to keep one lower limb raised from a supine position, in healthy subjects and in subjects with multiple sclerosis (MS) in two different conditions. The test required subjects to keep the right lower limb at 45° from the supine position on a horizontal bed plane, with the knee extended. The position was reached in two ways: by raising the right limb (A), and by resting the left lower limb on the bed after both limbs had been raised (B). During the test, pelvis and hip kinematics and the surface electromyographic (sEMG) activity were acquired. Fourteen healthy subjects and 14 subjects with multiple sclerosis were included in the study. Results showed that in the A condition, healthy subjects had a greater activation of the biceps femoris than the abdominal muscles, while in the B condition the difference between the two muscles decreased. In the MS group there was no difference in muscular activation for the two conditions. The data show that in the MS subjects there is an alteration of the stabilization muscles with regard the quality of the activation. Starting from these data new exercises of motor rehabilitation in subjects with multiple sclerosis could be recommended.

Spettroscopia protonica RM di lesioni isolate del tronco encefalico

1997 ◽  
Vol 10 (2_suppl) ◽  
pp. 37-38
Author(s):  
M. Cosottini ◽  
M. Mascalchi ◽  
M.C. Bianchi ◽  
M. Mortilla ◽  
M. Tosetti ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Brain Stem ◽  
Healthy Subjects ◽  
Brain Stem Glioma ◽  
Single Voxel ◽  
Neoplastic Lesions ◽  
Multiple Sclerosis Plaque ◽  
Brain Stem Lesions ◽  
Stem Lesions ◽  
Brain Stem Gliomas

Seven patients with solitary brain stem lesions (3 brain stem gliomas, 2 capillary telangectasias, 1 neuro-Behçet, 1 acute multiple sclerosis plaque) and 15 healthy volunteers were examined with single voxel proton MR speotroscopy using short TE STEAM or long TE PRESS techniques. The pontine spectrum in the healthy subjects showed a higher choline/creatine ratio than that observed in the normal supratentorial compartment. The three patients with brain stem glioma invariably showed a moderate to severe decrease of the N-acetyl-aspartate/creatine ratio associated with presence of lactate in two patients. The reduction of the N-acetyl aspartate/creatine ratio in the patients with non-neoplastic lesions was mild or absent and it was never associated with the presence of lactate. Even if further investigations are required to confirm these preliminary findings, our study indicates that proton MR speotroscopy may be of assistance in the differential diagnosis of neoplastic and non-neoplastic solitary brain stem lesions.

Mild hypoglycemia and impairment of brain stem and cortical evoked potentials in healthy subjects

Diabetes ◽  
1990 ◽  
Vol 39 (12) ◽  
pp. 1550-1555 ◽  
Author(s):  
T. W. Jones ◽  
G. McCarthy ◽  
W. V. Tamborlane ◽  
S. Caprio ◽  
E. Roessler ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Brain Stem ◽  
Healthy Subjects ◽  
Cortical Evoked Potentials

scholarly journals Bi-caudate ratio as a MRI marker of white matter atrophy in multiple sclerosis and ischemic leukocencephalopathy

2019 ◽  
Vol 50 (1) ◽  
Author(s):  
Dena Serag ◽  
Eman Ragab
Keyword(s):  
Multiple Sclerosis ◽  
White Matter ◽  
Surrogate Marker ◽  
Normal Subjects ◽  
Subjective Assessment ◽  
Linear Measurement ◽  
Control Group ◽  
Imaging Science ◽  
The Difference ◽  
Sensitivity Specificity

Abstract Background Brain atrophy measurement is now a cornerstone in basic neuro-imaging science. While assessment of white matter atrophy by visual inspection is subjective, volumetric approaches are time-consuming and not often feasible. Bi-caudate ratio represents a linear surrogate parameter of brain volume that can be derived from standard imaging sequences. This study highlights the value of the bi-caudate ratio (BCR) as a MRI marker of white matter atrophy in patients with multiple sclerosis and ischemic leukoencephalopathy and set a cut-off value to differentiate between patients with white matter atrophy and normal subjects. Results A total of 115 patients (54 males and 61 females) diagnosed with white matter leukoencephalopathy (MS in 51 patients and ischemic leukoencephalopathy in 64 patients) were included. Another group of 60 subjects with a normal white matter signal was recruited as a control group. BCR for the patient group ranged from 0.13 to 0.27 (mean (± SD) = 0.16 ± 0.02), while for the control group, it ranged from 0.05 mm to 0.13 (mean (± SD) = 0.09 ± 0.01). The difference between the two groups was statistically significant (P value < 0.001). A cut-off value of 0.13 was used to differentiate between the BCR in both patients and control groups with sensitivity, specificity, and accuracy of 99.2%, 100%, and 99%, respectively. The difference in BCR for patients diagnosed with MS and ischemic leukoencephalopathy was also statistically significant (P value < 0.001). Conclusion The bi-caudate ratio represents a linear measurement of subcortical atrophy that can be useful as a surrogate marker of global supra-tentorial white matter atrophy instead of the usually performed visual and therefore subjective assessment. It is an easily obtained measure that can be performed without complex time-consuming volumetric studies. Our findings also revealed that the BCR is higher in patients with ischemic leukoencephalopathy than in patients with MS.

scholarly journals The Brief International Cognitive Assessment in Multiple Sclerosis (BICAMS): Validation in Arabic and Lebanese Normative Values

2021 ◽  
pp. 1-10
Author(s):  
Hala Darwish ◽  
Pia Zeinoun ◽  
Natali Farran ◽  
Husam Ghusn ◽  
Bassem Yamout ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Psychometric Properties ◽  
Cognitive Assessment ◽  
Healthy Subjects ◽  
Good Evidence ◽  
Normative Values ◽  
Arabic Version ◽  
Retest Reliability ◽  
Test Retest Reliability ◽  
Healthy Participants

Abstract Objective: Multiple sclerosis (MS) is often associated with cognitive deficits. Accurate evaluation of the MS patients’ cognitive performance is essential for diagnosis and treatment recommendation. The Brief International Cognitive Assessment in Multiple Sclerosis (BICAMS), widely used cognitive testing battery, examines processing speed, verbal and visuospatial learning, and memory. Our study aims to examine the psychometric properties of an Arabic version of the BICAMS and to provide normative values in a Lebanese sample. Method: The BICAMS, comprised of the Symbol Digit Modalities Test (SDMT), Brief Visuospatial Memory Test-Revised (BVMT-R), and a newly developed verbal learning/memory test, the Verbal Memory Arabic Test (VMAT), were administered on healthy subjects and MS patients. The sample consisted of 180 healthy individuals, of whom 63 were retested after 2–3 weeks. Forty-three MS patients matched with 43 healthy subjects based on age, sex, and years of education were assessed. A sample of 10 MS patients was also examined on two occasions. Test–retest reliability and criterion-related validity were examined, and regression-based norms were derived. Results: The test–retest correlations showed good evidence of reliability with coefficients ranging between 0.64 and 0.73 in the healthy sample, and between 0.43 and 0.92 in the MS sample. The BICAMS was able to discriminate between MS patients and matched healthy participants on the SDMT and BVMT-R. Normative data were comparable to other studies. Conclusions: This new Arabic version of the BICAMS shows initial good psychometric properties. While good evidence of VMAT’s reliability was shown in the healthy participants, less test–retest reliability in this tool was seen in the MS group, and partial criterion-related validity was evident. This renders further examination of the VMAT. We provide regression-based norms for a Lebanese sample and encourage the use of this battery in both research and clinical settings.

scholarly journals Biomechanical analysis of an unpowered hip flexion orthosis on individuals with and without multiple sclerosis

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Ross M. Neuman ◽  
Staci M. Shearin ◽  
Karen J. McCain ◽  
Nicholas P. Fey
Keyword(s):  
Multiple Sclerosis ◽  
Muscle Activity ◽  
Healthy Subjects ◽  
Muscle Activation ◽  
Assistive Technologies ◽  
Lower Limbs ◽  
Biomechanical Analysis ◽  
Foot Drop ◽  
Plantar Flexors ◽  
Hip Flexion

Abstract Background Gait impairment is a common complication of multiple sclerosis (MS). Gait limitations such as limited hip flexion, foot drop, and knee hyperextension often require external devices like crutches, canes, and orthoses. The effects of mobility-assistive technologies (MATs) prescribed to people with MS are not well understood, and current devices do not cater to the specific needs of these individuals. To address this, a passive unilateral hip flexion-assisting orthosis (HFO) was developed that uses resistance bands spanning the hip joint to redirect energy in the gait cycle. The purpose of this study was to investigate the short-term effects of the HFO on gait mechanics and muscle activation for people with and without MS. We hypothesized that (1) hip flexion would increase in the limb wearing the device, and (2) that muscle activity would increase in hip extensors, and decrease in hip flexors and plantar flexors. Methods Five healthy subjects and five subjects with MS walked for minute-long sessions with the device using three different levels of band stiffness. We analyzed peak hip flexion and extension angles, lower limb joint work, and muscle activity in eight muscles on the lower limbs and trunk. Single-subjects analysis was used due to inter-subject variability. Results For subjects with MS, the HFO caused an increase in peak hip flexion angle and a decrease in peak hip extension angle, confirming our first hypothesis. Healthy subjects showed less pronounced kinematic changes when using the device. Power generated at the hip was increased in most subjects while using the HFO. The second hypothesis was not confirmed, as muscle activity showed inconsistent results, however several subjects demonstrated increased hip extensor and trunk muscle activity with the HFO. Conclusions This exploratory study showed that the HFO was well-tolerated by healthy subjects and subjects with MS, and that it promoted more normative kinematics at the hip for those with MS. Future studies with longer exposure to the HFO and personalized assistance parameters are needed to understand the efficacy of the HFO for mobility assistance and rehabilitation for people with MS.

Reaction time in ambulant multiple sclerosis patients

1988 ◽  
Vol 85 (2) ◽  
pp. 187-196 ◽  
Author(s):  
A. Jennekens-Schinkel ◽  
E.A.C.M. Sanders ◽  
J.B.K. Lanser ◽  
E.A. Van der Velde
Keyword(s):  
Multiple Sclerosis ◽  
Reaction Time ◽  
Multiple Sclerosis Patients

scholarly journals Involvement of the Inconstant Bursa of the Fifth Metatarsophalangeal Joint in Psoriatic Arthritis: A Clinical and Ultrasonographic Study

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Giovanni Ciancio ◽  
Stefania Volpinari ◽  
Maria Fotinidi ◽  
Federica Furini ◽  
Ilaria Farina ◽  
...  
Keyword(s):  
Psoriatic Arthritis ◽  
Healthy Subjects ◽  
Statistical Significance ◽  
Metatarsophalangeal Joint ◽  
Metatarsal Bone ◽  
The Other ◽  
Control Group ◽  
Asymptomatic Patients ◽  
Seronegative Spondyloarthritis ◽  
The Difference

Objective. To evaluate the involvement of the bursa located next to the head of the 5th metatarsal bone in patients with psoriatic arthritis (PsA) in comparison with the other seronegative spondyloarthritis (SpA).Methods. All patients with PsA seen during a period of 24 months were enrolled. The control group included healthy subjects and patients with the other SpA. All subjects underwent clinical and ultrasound (US) examination of the lateral surface of the 5th metatarsal.Results. 150 PsA patients (88 M; 62 F), 172 SpA (107 M; 65 F), and 95 healthy controls (58 M; 37 F) were evaluated. Based on clinical and US evaluation, bursitis was diagnosed in 17/150 (11.3%) PsA patients but in none of the SpA (P<0.0001) and healthy (P=0.0002) controls. In detecting bursitis, US was more sensitive than clinical examination, although the difference did not reach statistical significance (P=0.09).Conclusion. The bursa of the 5th metatarsophalangeal joint appears to be involved in PsA more frequently than by chance. If confirmed by other studies, this finding could be considered as a distinctive clinical sign of PsA, useful for differential diagnosis with the other SpA. In asymptomatic patients, US proved to be more sensitive in the detection of bursitis.

Limits to the Control of the Human Thumb and Fingers in Flexion and Extension

2010 ◽  
Vol 103 (1) ◽  
pp. 278-289 ◽  
Author(s):  
W. S. Yu ◽  
H. van Duinen ◽  
S. C. Gandevia
Keyword(s):  
Control System ◽  
Healthy Subjects ◽  
Neural Control ◽  
Force Production ◽  
Total Force ◽  
Neural Drive ◽  
Antagonist Muscles ◽  
Hand Performance ◽  
The Difference ◽  
Flexion And Extension

In humans, hand performance has evolved from a crude multidigit grasp to skilled individuated finger movements. However, control of the fingers is not completely independent. Although musculotendinous factors can limit independent movements, constraints in supraspinal control are more important. Most previous studies examined either flexion or extension of the digits. We studied differences in voluntary force production by the five digits, in both flexion and extension tasks. Eleven healthy subjects were instructed either to maximally flex or extend their digits, in all single- and multidigit combinations. They received visual feedback of total force produced by “instructed” digits and had to ignore “noninstructed” digits. Despite attempts to maximally flex or extend instructed digits, subjects rarely generated their “maximal” force, resulting in a “force deficit,” and produced forces with noninstructed digits (“enslavement”). Subjects performed differently in flexion and extension tasks. Enslavement was greater in extension than in flexion tasks ( P = 0.019), whereas the force deficit in multidigit tasks was smaller in extension ( P = 0.035). The difference between flexion and extension in the relationships between the enslavement and force deficit suggests a difference in balance of spillover of neural drive to agonists acting on neighboring digits and focal neural drive to antagonist muscles. An increase in drive to antagonists would lead to more individualized movements. The pattern of force production matches the daily use of the digits. These results reveal a neural control system that preferentially lifts fingers together by extension but allows an individual digit to flex so that the finger pads can explore and grasp.

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