Influence of visual and proprioceptive afferences on upper limb ataxia in patients with multiple sclerosis

Effects of Peripheral Cooling on Upper Limb Tremor Severity and Functional Capacity in Persons with MS

Upper limb intention tremor in persons with multiple sclerosis (pwMS) affects the ability to perform activities of daily life and is difficult to treat. The study investigated the effect of peripheral upper limb cooling on tremor severity and functional performance in MS patients with intention tremor. In experiment 1, 17 patients underwent two 15 min cooling conditions for the forearm (cold pack and cryomanchet) and one control condition. In experiment 2, 22 patients underwent whole arm cooling for 15 min using multiple cold packs. In both experiments, patients were tested at four time points (pre- and post-0, -25 and -50 min cooling) on unilateral tasks of the Test Evaluant les Membres supérieurs des Personnes Agées (TEMPA), Fahn's tremor rating scale (FTRS), Nine Hole Peg Test (NHPT). In experiment 1, the mean FTRS ranged from 13.2 to 14.1 across conditions. A two-way ANOVA showed mainly time effects, showing that cooling the forearm significantly reduced the FTRS, the performance on the NHPT, and three out of four items of the TEMPA, mostly independent of the cooling modality. In experiment 2, the mean FTRS was 13.1. A repeated measures ANOVA showed that cooling the whole arm reduced the FTRS and time needed to execute two out of four items of the TEMPA. These effects occurred immediately after cooling lasting at least 25 min. Cooling the whole upper limb led to a clinically noticeable effect on tremor severity and improved functional performance, which was pronounced during the first half-hour after cooling.

Change in upper limb function in people with multiple sclerosis treated with nabiximols: a quantitative kinematic pilot study

OBJECTIVES

Nabiximols represents an increasingly employed add-on treatment option for spasticity in people with multiple sclerosis (PwMS) who either were unresponsive or reported excessive adverse reactions to other therapies. While several studies performed in the last decade demonstrated its effectiveness, safety, and tolerability, few quantitative data are available on the impact on motor dysfunctions. In this open-label, not concurrently controlled study, we aimed to assess the impact of a 4-week treatment with nabiximols on upper limb functionality.

METHODS

Thirteen PwMS (9 female, 4 male) with moderate-severe spasticity underwent a combination of clinical tests (i.e., Box and Block, BBT and Nine-Hole Peg test, 9HPT) and instrumental kinematic analysis of the "hand to mouth" (HTM) movement by means of optical motion capture system.

RESULTS

After the treatment, improvements in gross and fine dexterity were found (BBT + 3 blocks/min, 9HPT - 2.9 s, p < 0.05 for both cases). The kinematic analysis indicated that HTM movement was faster (1.69 vs. 1.83 s, p = 0.05), smoother, and more stable. A significant reduction of the severity of spasticity, as indicated by the 0-10 numerical rating scale (4.2 vs. 6.3, p < 0.001), was also observed.

CONCLUSION

The findings from the present pilot study suggest that a 4-week treatment with nabiximols ameliorates the spasticity symptoms and the overall motor function of upper limb in PwMS with moderate-severe spasticity. The use of quantitative techniques for human movement analysis may provide valuable information about changes originated by the treatment in realistic upper limb motor tasks involved in activities of daily living.

Effect of immersive virtual reality training on hand-to-mouth task performance in people with Multiple Sclerosis: A quantitative kinematic study

BACKGROUND

Although the use of Virtual Reality (VR) has received increasing interest as an add-on treatment in neurorehabilitation programs in the last fifteen years, there is scarce information about the effectiveness of fully immersive VR-based treatments on upper limb (UL) motor function in people with Multiple Sclerosis (PwMS).

METHODS

In this bicentric 2-period interventional crossover study, 19 PwMS with moderate to severe disability (mean EDSS score 5.5) and relevant UL impairment underwent 12 immersive-VR sessions over a period of 4 weeks, using commercially available VR platform (Oculus Quest) and games (Fruit Ninja, Beat Saber and Creed - Rise to Glory). Possible changes associated with the treatment were objectively assessed through instrumental kinematic analysis of the "hand-to-mouth" (HTM) movement by means of optical motion capture system. Clinical tests to assess gross and fine manual dexterity (i.e., the Box and Blocks and Nine Hole Peg Test) were also administered.

RESULTS

The results of the kinematic analysis suggest that the VR training positively impacted the ability of the tested PwMS to perform the HTM task. In particular, a significant reduction of the overall time required to complete the task of approximately 20% for both most and least affected limb, and an improved degree of precision and stability of the movement, as indicated by the reduced value of adjusting sway, especially for the most affected limb (-60%).

CONCLUSION

Based on the results of the quantitative analysis, a 4-week treatment with immersive VR is able to improve speed and stability of the HTM movement in PwMS. This suggests that such an approach might be considered suitable to facilitate an immediate transfer of the possible positive effects associated with the training to common activities of daily living.

Assessing proprioceptive acuity in people with multiple sclerosis

Background

Proprioceptive acuity and impairments in proprioceptively guided reaches have not been comprehensively examined in people with multiple sclerosis (MS).

Objective

To examine proprioceptive acuity in people with MS who self-report and who do not self-report upper limb (UL) impairment, and to determine how people with MS reach proprioceptive targets.

Methods

Twenty-four participants with MS were recruited into two groups based on self-reported UL impairment: MS-R (i.e. report UL impairment; n  =  12) vs. MS-NR (i.e. do not report UL impairment; n  =  12). Proprioception was assessed using ipsilateral and contralateral robotic proprioceptive matching tasks.

Results

Participants in the MS-R group demonstrated worse proprioceptive acuity compared to the MS-NR group on the ipsilateral and contralateral robotic matching tasks. Analyses of reaches to proprioceptive targets further revealed that participants in the MS-R group exhibited deficits in movement planning, as demonstrated by greater errors at peak velocity in the contralateral matching task in comparison to the MS-NR group.

Conclusion

Our findings suggest that people with MS who self-report UL impairment demonstrate worse proprioceptive acuity, as well as poorer movement planning in comparison to people with MS who do not report UL impairment.

Assessing visually guided reaching in people with multiple sclerosis with and without self-reported upper limb impairment

The ability to accurately complete goal-directed actions, such as reaching for a glass of water, requires coordination between sensory, cognitive and motor systems. When these systems are impaired, like in people with multiple sclerosis (PwMS), deficits in movement arise. To date, the characterization of upper limb performance in PwMS has typically been limited to results attained from self-reported questionnaires or clinical tools. Our aim was to characterize visually guided reaching performance in PwMS. Thirty-six participants (12 PwMS who reported upper limb impairment (MS-R), 12 PwMS who reported not experiencing upper limb impairment (MS-NR), and 12 age- and sex-matched control participants without MS (CTL)) reached to 8 targets in a virtual environment while seeing a visual representation of their hand in the form of a cursor on the screen. Reaches were completed with both the dominant and non-dominant hands. All participants were able to complete the visually guided reaching task, such that their hand landed on the target. However, PwMS showed noticeably more atypical reaching profiles when compared to control participants. In accordance with these observations, analyses of reaching performance revealed that the MS-R group was more variable with respect to the time it took to initiate and complete their movements compared to the CTL group. While performance of the MS-NR group did not differ significantly from either the CTL or MS-R groups, individuals in the MS-NR group were less consistent in their performance compared to the CTL group. Together these findings suggest that PwMS with and without self-reported upper limb impairment have deficits in the planning and/or control of their movements. We further argue that deficits observed during movement in PwMS who report upper limb impairment may arise due to participants compensating for impaired movement planning processes.

Evaluation of upper extremity ataxia through image processing in individuals with multiple sclerosis

BACKGROUND

Impaired dexterity is a frequently reported disability among people with ataxic multiple sclerosis (MS).

OBJECTIVE

To quantify and standardize the evaluation of upper extremity coordination disorder among patients with multiple sclerosis (MS), using the Tablet Ataxia Assessment Program (TAAP).

METHODS

The X and Y axis movements of 50 MS patients and 30 healthy individuals who were evaluated using the International Cooperative Ataxia Rating Scale (ICARS) were also assessed using TAAP. The functional times of the participants' right and left hands were recorded using the nine-hole peg test (NHPT). The upper extremity coordination of individuals with MS was evaluated using the upper extremity kinetic functions section of ICARS.

RESULTS

The deviations for the X and Y axis movements of the MS group were greater than those of the control group (p<0.05). Significant correlations were shown between TAAP scores and NHPT and ICARS scores. The strongest correlation was found between NHPT and ICARS in the dominant hand (rnhpt=0.356, pnhpt=0.001; ricars=0.439, picars=0.000). In correlating the Y axis with ICARS, the deviations in the Y axis were found to be greater in the non-dominant hand than those in the X axis (ryright=0.402, pyright=0.004; ryleft=0.691, pyleft=0.000).

CONCLUSION

Measurement using TAAP is more sensitive than other classical and current methods for evaluating ataxia. We think that TAAP is an objective tool that will allow neurorehabilitation professionals and clinicians to evaluate upper extremity coordination.

Is There Any Relationship between Upper and Lower Limb Impairments in People with Multiple Sclerosis? A Kinematic Quantitative Analysis

Background

In people with multiple sclerosis (pwMS), disability is generally assessed on the basis of ambulation abilities, whereas upper limb motor dysfunctions are less frequently considered. Nevertheless, they can severely affect the quality of life of pwMS. To date, it remains mostly unknown whether a relationship exists between upper and lower limb impairments.

Aim

To investigate the existence of a relationship between upper and lower limb impairments in pwMS based on two fundamental motor tasks, namely walking and hand-to-mouth (HTM) movement.

Methods

Twenty-eight pwMS with Expanded Disability Status Scale (EDSS) scores in the range of 1-6, and 21 healthy controls (HC) underwent a kinematic analysis of gait and HTM movement performed with a motion capture system. The spatiotemporal parameters for the two tasks were calculated and correlated using Spearman's rank correlation coefficients.

Results

The pwMS performed worse than HC on both tasks. Small to large correlations were found between the total HTM movement duration and most of the gait parameters (rho, 0.35-0.68; p < 0.05).

Conclusions

Both upper and lower limb motor abilities in pwMS worsen as disability increases. Nevertheless, their relationship is only moderate. This finding emphasizes the need for specific tests to quantify disability considering the overall motor function in pwMS.

Quantitative assessment of upper limb functional impairments in people with Parkinson's disease

BACKGROUND

In clinical routine, upper limb motor disorders of people with Parkinson's disease are commonly assessed using scale- or timed tests, but such tools are not fully suitable for providing detailed information about their type and magnitude. To partly overcome these limitations, the present study aims to quantitatively investigate upper limb functional impairments through quantitative analysis of the "hand-to-mouth" task.

METHODS

Twenty-five individuals with Parkinson's disease and 20 age-matched healthy individuals underwent a kinematic analysis of the hand-to-mouth task from which spatio-temporal and kinematic measures, including summary measures (Arm Variable Score and Arm Profile Score), were calculated and correlated with clinical scores (Hoehn & Yahr, H&Y and the Unified Parkinson Disease Rating Scale, UPDRS).

FINDINGS

The "hand-to-mouth" movement is significantly altered in individuals with Parkinson's disease, especially in terms of reduced velocity, reduced range of motion of elbow flexion-extension and deviation from a physiologic pattern (Arm Profile Score 12.8° vs. 10.1° of unaffected, P = 0.002). Significant moderate correlations were found between movement duration and UPDRS-III (rho = 0.478, P = 0.001) and between the Arm Profile Score and H&Y (rho = 0.481, P = 0.024) and UPDRS-III (rho = 0.326, P = 0.001).

INTERPRETATION

On the basis of such findings, we can state that the kinematic analysis of "hand-to-mouth" movement, and in particular the summary indexes, are suitable for easily representing upper limb movement alterations in people with Parkinson's disease, thus allowing the monitoring either of disease progression or effectiveness of pharmacologic and rehabilitative treatments.

Validation of the Arm Profile Score in assessing upper limb functional impairments in people with multiple sclerosis

BACKGROUND

Although upper limb (UL) impairments are widespread in people with Multiple Sclerosis (pwMS), there is limited quantitative evidence concerning their specific features. The aim of this study is to validate a synthetic measure based on kinematic data to define the degree of deviation from a physiologic pattern during the "hand to mouth" (HTM) task.

METHODS

Twenty pwMS (mean age 51.2 SD 11.1) years, Expanded Disability Status Scale (EDSS) score in the range 2-6.5, underwent a kinematic analysis of the HTM task using a motion capture system. Spatio-temporal parameters and synthetic indexes (Arm Variable Score, AVS and Arm Profile Score, APS) were calculated and compared with those of age-matched healthy individuals. Kinematic data were correlated with the EDSS score and clinical tests such as the Nine Hole Peg Test (NHPT) and hand-grip strength (HGS).

FINDINGS

PwMS exhibit reduced velocity, increased movement duration, sway of adjusting and frequency of direction changes as well as higher APS values (15.4° vs. 8.6°, P<0.001) with respect to controls due to alterations in trunk flexion-extension, shoulder abduction-adduction, flexion-extension and rotation and elbow flexion-extension. Moderate-to-large correlations were found between APS and EDSS (rho=0.609, P<0.001), NHPT (rho=0.468, P=0.03) and HGS (rho=-0.627 P<0.001).

INTERPRETATION

The kinematic analysis of HTM provides useful information in quantifying UL impairments in pwMS. The APS index appears suitable to represent UL movement deviations from the physiological pattern in pwMS and to assess disease progression or effectiveness of pharmacologic and rehabilitative treatments effectiveness.

Neuromuscular taping for the upper limb in Cerebral Palsy: A case study in a patient with hemiplegia

OBJECTIVE

To assess quantitatively the effects of Neuromuscular Taping (NMT) on the upper limb in a female child with left hemiplegia, due to Cerebral Palsy (CP).

METHODS

The patient underwent NMT on cervical level, shoulder and hand only of the plegic upper limb, followed by physical therapy. Kinematic data of upper limbs during reaching task were collected before (PRE) and after 2 weeks of treatment (POST).

RESULTS

After the intervention, the affected limb improved in terms of movement duration, Average Jerk and Number of Unit Movements indices, indicating a faster, smoother and less segmented movement. Improvements appeared at the ranges of motion of the upper limb joints, both at shoulder and elbow joints. No significant changes were globally displayed for the unaffected arm.

CONCLUSION

NMT seems to be a promising intervention for improving upper limb movement in patients with CP. Further investigations are certainly needed to assess effectively the effects of the intervention in this pathological state.

[The use of neuromodulation for the treatment of tremor]

BACKGROUND

Tremor may be a disabling disorder and pharmacologic treatment is the first-line therapy for these patients. Nevertheless, this treatment may lead to a satisfactory tremor reduction in only 50% of patients with essential tremor. Thalamotomy was the treatment of choice for tremor refractory to medical therapy until deep brain stimulation (DBS) of the ventral intermedius nucleus (Vim) of the thalamus has started being used. Nowadays, thalamotomy is rarely performed.

METHODS

This article is a non-systematic review of the indications, results, programming parameters and surgical technique of DBS of the Vim for the treatment of tremor.

RESULTS

In spite of the fact that it is possible to achieve similar clinical results using thalamotomy or DBS of the Vim, the former causes more adverse effects than the latter. Furthermore, DBS can be used bilaterally, whereas thalamotomy has a high risk of causing disartria when it is performed in both sides. DBS of the Vim achieved an adequate tremor improvement in several series of patients with tremor caused by essential tremor, Parkinson's disease or multiple sclerosis. Besides the Vim, there are other targets, which are being used by some authors, such as the zona incerta and the prelemniscal radiations.

CONCLUSION

DBS of the Vim is a useful treatment for disabling tremor refractory to medical therapy. It is essential to carry out an accurate patient selection as well as to use a proper surgical technique. The best stereotactic target for tremor is still unknown, although the Vim is the most used one.

Understanding tremor in multiple sclerosis: prevalence, pathological anatomy, and pharmacological and surgical approaches to treatment

Background

Given that tremor is one of the most prevalent and disabling features of multiple sclerosis (MS), we will review the most significant milestones in tremor in this disease in recent years, focusing on prevalence, clinical features, anatomical basis, and treatment.

Methods

Data for this review were identified by searching MEDLINE with the search terms “multiple sclerosis” and “tremor”. References were also identified from relevant articles published between January 1966 and May 2012.

Results

The predominant type of MS tremor is a large-amplitude, postural, and kinetic tremor, which most commonly affects the arms, although tremor can also involve head, neck, vocal cords, and trunk. Involvement of the tongue, jaw, or palate has not been reported. Although the anatomical basis underlying tremor in MS is poorly understood, the link between the cerebellum and the MS-related tremor is supported by clinical and experimental studies. Currently available medication is often unsuccessful in most cases. Surgical treatment can be a satisfactory alternative to treat severe and disabling tremor.

Discussion

Tremor in MS patients could be considered as an advanced consequence of the disease and its presence suggests a more aggressive course. MS tremor can be severe and very disabling for a small group of patients. Treatment of MS tremor remains a great challenge. Recent studies suggest that dissociating tremor from cerebellar dysfunction using selected clinical tests would be the key issue to successful surgical treatment. Understanding the pathophysiology and biochemistry of tremor production in MS may lead to new therapeutic approaches.

Cerebellar ataxia: pathophysiology and rehabilitation

This series of articles for rehabilitation in practice aims to cover a knowledge element of the rehabilitation medicine curriculum. Nevertheless they are intended to be of interest to a multidisciplinary audience. The competency addressed in this article is 'The trainee consistently demonstrates a knowledge of management approaches for specific impairments including spasticity, ataxia.'

Movement disorders in patients with multiple sclerosis

Apart from tremor and restless-legs syndrome, abnormal involuntary movements are uncommon in patients with multiple sclerosis. A review of the literature in multiple sclerosis reveals case reports of a variety of other movement disorders such as myoclonus, spasmodic torticollis, paroxysmal dystonia, chorea, ballism, and parkinsonism. This chapter presents a thorough review of these movement disorders in multiple sclerosis patients and provides readers with potential underlying pathogenetic mechanisms.

Adaptive robot training for the treatment of incoordination in Multiple Sclerosis

BACKGROUND

Cerebellar symptoms are extremely disabling and are common in Multiple Sclerosis (MS) subjects. In this feasibility study, we developed and tested a robot therapy protocol, aimed at the rehabilitation of incoordination in MS subjects.

METHODS

Eight subjects with clinically defined MS performed planar reaching movements while grasping the handle of a robotic manipulandum, which generated forces that either reduced (error-reducing, ER) or enhanced (error-enhancing, EE) the curvature of their movements, assessed at the beginning of each session. The protocol was designed to adapt to the individual subjects' impairments, as well as to improvements between sessions (if any). Each subject went through a total of eight training sessions. To compare the effect of the two variants of the training protocol (ER and EE), we used a cross-over design consisting of two blocks of sessions (four ER and four EE; 2 sessions/week), separated by a 2-weeks rest period. The order of application of ER and EE exercises was randomized across subjects. The primary outcome measure was the modification of the Nine Hole Peg Test (NHPT) score. Other clinical scales and movement kinematics were taken as secondary outcomes.

RESULTS

Most subjects revealed a preserved ability to adapt to the robot-generated forces. No significant differences were observed in EE and ER training. However over sessions, subjects exhibited an average 24% decrease in their NHPT score. The other clinical scales showed small improvements for at least some of the subjects. After training, movements became smoother, and their curvature decreased significantly over sessions.

CONCLUSIONS

The results point to an improved coordination over sessions and suggest a potential benefit of a short-term, customized, and adaptive robot therapy for MS subjects.

Tremor in multiple sclerosis

Tremor is estimated to occur in about 25 to 60 percent of patients with multiple sclerosis (MS). This symptom, which can be severely disabling and embarrassing for patients, is difficult to manage. Isoniazid in high doses, carbamazepine, propranolol and gluthetimide have been reported to provide some relief, but published evidence of effectiveness is very limited. Most trials were of small size and of short duration. Cannabinoids appear ineffective. Tremor reduction can be obtained with stereotactic thalamotomy or thalamic stimulation. However, the studies were small and information on long-term functional outcome is scarce. Physiotherapy, tremor reducing orthoses, and limb cooling can achieve some functional improvement. Tremor in MS remains a significant challenge and unmet need, requiring further basic and clinical research.

Subtle upper limb impairment in asymptomatic multiple sclerosis subjects

We evaluated upper limb function in multiple sclerosis (MS) subjects (11 clinically definite MS patients and seven clinically isolated syndrome (CIS) subjects), with a normal upper limb standard neurological examination. Subjects performed center-out reaching movements under visual control, with and without vision of the hand. Their movements were recorded through a digitizing tablet. Motor performance was also related to lesion load, estimated from magnetic resonance imaging (MRI). We found that in MS and CIS subjects, under the hand vision condition, movements were significantly less smooth, and had a less symmetric speed profile. However, the observed impairment did not correlate with MRI findings. This result may be interpreted as evidence of a compensatory strategy, elicited by subtle alterations in sensorimotor control. Multiple Sclerosis 2007; 13: 428-432. http://msj.sagepub.com

Treatment for ataxia in multiple sclerosis

BACKGROUND

Disabling tremor or ataxia is common in multiple sclerosis (MS) and up to 80% of patients experience tremor or ataxia at some point during their disease. A variety of treatments are available, ranging from pharmacotherapy or stereotactic neurosurgery to neurorehabilitation.

OBJECTIVES

To assess the efficacy and tolerability of both pharmacological and non-pharmacologic treatments of ataxia in patients with MS.

SEARCH STRATEGY

The following electronic resources were searched: Cochrane MS Group trials register (June 2006), the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 2, 2006), National Health Service National Research Register (NRR) including the Medical Research Council Clinical Trials Directory (Issue 2, 2006), MEDLINE (January 1996 to June 2006), and EMBASE (Jan 1988 to June 2006). Manual searches of bibliographies of relevant articles, pertinent medical and neurology journals and abstract books of major neurology and MS conferences (2001-2006) were also performed. Direct communication with experts and drug companies was sought.

SELECTION CRITERIA

Blinded, randomised trials which were either placebo-controlled or which compared two or more treatments were included. Trials testing pharmacological agents must have had both participant and assessor blinding. Trials testing surgical interventions or effects of physiotherapy, where participants could not have been blinded to the treatment, must have had independent assessors who were blinded to the treatment. Cross-over trials were included.

DATA COLLECTION AND ANALYSIS

Three independent reviewers extracted data and the findings of the trials were summarised. A meta-analysis was not performed due to the inadequacy of outcome measures and methodological problems with the studies reviewed.

MAIN RESULTS

Ten randomised controlled trials met the inclusion criteria. Six placebo-controlled studies (pharmacotherapy) and four comparative studies (one stereotactic neurosurgery and three neurorehabilitation) were reviewed. No standardised outcome measures were used across the studies. In general, pharmacotherapies were unrewarding and data on neurosurgery or rehabilitation is insufficient to lead to a change in practice.

AUTHORS' CONCLUSIONS

The absolute and comparative efficacy and tolerability of pharmacotherapies to treat ataxia in MS are poorly documented and no recommendations can be made to guide prescribing. Although studies on neurosurgery and neurorehabilitation showed promising results, the absolute indications for treating with those methods cannot be developed. Standardised, well validated measures of ataxia and tremor need to be developed and employed in larger randomised controlled trials with careful blinding.

Moderate alterations in lower limbs muscle temperature do not affect postural stability during quiet standing in both young and older women

Older adults demonstrate increased amounts of postural sway, which may ultimately lead to falls. Temperature is known to have a profound effect on the performance of the neuromuscular system which could have important implications on motor control. It is, therefore, of interest to investigate if the age-related decline in postural stability could be affected by changes in local limbs temperature. The present study investigated the effects of localized warming and cooling on postural sway in nine young (22+/-3 years) and nine older (73+/-3 years) women. Postural sway was assessed, using a single force platform, during quiet standing at three muscle temperature conditions: control (34.2+/-0.2 degrees C), cold (31.3+/-0.3 degrees C) and warm (37.0+/-0.1 degrees C). Two stances were evaluated, the Romberg (large support base) and modified Tandem (narrow support base), under both eyes-open and eyes-closed conditions. Root mean square (RMS), mean velocity (MV), sway area (SA) and mean power frequency (MPF) were calculated from the centre of pressure (COP) displacement. Neither warming nor cooling significantly affected any of the postural parameters which were, however, all higher (P<0.05) in the older group than the young group in all conditions. This study demonstrated that, in quiet standing conditions, a moderate variation (+/-3 degrees C) in lower limbs temperature does not affect postural steadiness in either young or older women.

Effects of peripheral cooling on intention tremor in multiple sclerosis

OBJECTIVE

To investigate the effect of peripheral sustained cooling on intention tremor in patients with multiple sclerosis (MS). MS induced upper limb intention tremor affects many functional activities and is extremely difficult to treat.Materials/

METHODS

Deep (18 degrees C) and moderate (25 degrees C) cooling interventions were applied for 15 minutes to 23 and 11 tremor arms of patients with MS, respectively. Deep and moderate cooling reduced skin temperature at the elbow by 13.5 degrees C and 7 degrees C, respectively. Evaluations of physiological variables, the finger tapping test, and a wrist step tracking task were performed before and up to 30 minutes after cooling.

RESULTS

The heart rate and the central body temperature remained unchanged throughout. Both cooling interventions reduced overall tremor amplitude and frequency proportional to cooling intensity. Tremor reduction persisted during the 30 minute post cooling evaluation period. Nerve conduction velocity was decreased after deep cooling, but this does not fully explain the reduction in tremor amplitude or the effects of moderate cooling. Cooling did not substantially hamper voluntary movement control required for accurate performance of the step tracking task. However, changes in the mechanical properties of muscles may have contributed to the tremor amplitude reduction.

CONCLUSIONS

Cooling induced tremor reduction is probably caused by a combination of decreased nerve conduction velocity, changed muscle properties, and reduced muscle spindle activity. Tremor reduction is thought to relate to decreased long loop stretch reflexes, because muscle spindle discharge is temperature dependent. These findings are clinically important because applying peripheral cooling might enable patients to perform functional activities more efficiently.

Interaction between eye and hand movements in multiple sclerosis patients with intention tremor

Deficient eye and hand movements are present in patients with multiple sclerosis. In the present study, eye and hand movements were simultaneously measured during visually guided wrist step-tracking tasks in 16 patients with intention tremor and 15 healthy controls. The coupling between eye and hand movements was analyzed during simultaneous eye-hand tracking, and interactions were studied by comparing the coordinated eye-hand condition with isolated eye- or hand-tracking conditions. Despite movement abnormalities, the onset of eye and hand movements was highly correlated and an invariant coupling between the saccadic completion time and hand peak velocity was found, suggesting that the temporal coupling was very much preserved. The differences between the experimental tracking conditions suggest that, in MS patients with intention tremor, the ocular system influenced the hand movements. Intention tremor amplitude was reduced when there was no preceding saccadic eye movement, whereas conversely, eye movements were not affected by different hand tremor severity.

Augmented visual feedback increases finger tremor during postural pointing

Physiological tremor in the upper limb of eight adults was examined during the performance of a unilateral pointing task under conditions where the visual feedback, limb used and target size were altered. All subjects were required to aim a hand-held laser pointer at a circular target 5.5 m away with the goal of keeping the laser emission within the centre of the target. Visual feedback was defined as either normal vision (NV) of their limb tremor, where the laser was switched off, or augmented vision (AV) where the laser was switched on. Postural tremor from the segments of the upper limb, forearm muscle EMG activity, and target accuracy measures were recorded and analysed in the time and frequency domains. Accuracy-tremor relations were assessed using cross correlation and linear regression. Results revealed a high degree of similarity in the general pattern of the tremor output seen for each limb segment across conditions with only scalar (amplitude) changes being seen as a function of the different constraints imposed. For any single condition the tremor amplitude increased from proximal to distal segments. The frequency profile for the tremor in any segment displayed two prominent frequency peaks (at 2-4 Hz and 8-12 Hz). A third, higher frequency peak (18-22 Hz) was observed in the index fingers only. Across all conditions significant coupling relations were observed only between the hand-finger and forearm-upper arm segment pairs. Altering the visual feedback was shown to have the greatest effect on limb tremor with increased tremor and EMG activity and decreased coupling being seen under AV conditions. In trying to reduce tremor output when the augmented feedback was provided novice subjects instead increased muscle activity which resulted in increased tremor. Overall these results indicate that the physiological tremor output observed in neurologically normal subjects is not simply the product of intrinsic oscillations but is influenced by the nature of the task being performed.

Group II spindle fibres and afferent control of stance. Clues from diabetic neuropathy

OBJECTIVE

Since patients with large-fibre neuropathy do not show abnormal body sway during stance, the hypothesis was tested that postural control is not impaired until myelinated fibres of medium size are affected.

METHODS

In 22 diabetic neuropathic patients and 13 normals, we recorded: (1) body sway area (SA), (2) stretch responses of soleus (Sol) and flexor digitorum brevis (FDB) to toe-up rotation of a platform, (3) Sol and FDB H reflex and FDB F wave, (4) conduction velocity (CV) of tibial, deep peroneal and sural nerve. In patients, detection thresholds for vibration, cooling (CDT), warming and heat-pain (HPDT) were assessed.

RESULTS

Body SA was increased in patients with respect to normals. Toe-up rotation elicited short- (SLR) and medium-latency (MLR) responses in Sol and FDB in all normals. In patients, SLR was absent in FDB and reduced in Sol, and MLR was delayed in both muscles; the FDB H reflex was absent. The CV of tibial nerve group II afferent fibres, as estimated from the afferent time of FDB MLR, was reduced in patients. All sensory detection thresholds were increased. Stepwise multiple regression showed that increased SA was explained by increased latency of MLR, decreased CV of group II fibres and augmented CDT and HPDT.

CONCLUSIONS

Unsteadiness in diabetic neuropathy is related to alterations in medium-size myelinated afferent fibres, possibly originating from spindle secondary terminations.

Intention tremor during manual aiming: a study of eye and hand movements

Accurate goal-directed movements toward a visual target require a precise coordination of both the oculomotor and limb motor systems. Intention tremor and eye movement deficits are frequently observed in multiple sclerosis (MS). The goal of this study was to examine the characteristics of intention tremor and simultaneously produced eye movements during rapid goal-directed movements. Eye and hand movements were synchronously measured in 16 MS patients with intention tremor and 16 control subjects. Manual performances of the patient group were characterized by a delayed onset, slower execution and aiming inaccuracies. In line with the clinically defined picture of intention tremor differences between patients and control subjects were most pronounced toward the end of the movement. Dependent variables were obviously greater in MS patients compared with control subjects, and correlated well with clinical outcome measures. The application of an inertial load to the limb did not show any effect on intention tremor. In addition to impaired limb coordination, evidence has been found that eye movements, too, were abnormal in patients compared with control subjects. Moreover, eye and hand movement deficits seemed to be closely related, suggesting a common underlying command structure. Inaccurate eye movements were likely to hamper an accurate motor performance of the hand.

Physiotherapy approaches in the treatment of ataxic multiple sclerosis: a pilot study

OBJECTIVE

This study was planned to investigate the efficacy of neuromuscular rehabilitation and Johnstone Pressure Splints in the patients who had ataxic multiple sclerosis.

METHODS

Twenty-six outpatients with multiple sclerosis were the subjects of the study. The control group (n = 13) was given neuromuscular rehabilitation, whereas the study group (n = 13) was treated with Johnstone Pressure Splints in addition.

RESULTS

In pre- and posttreatment data, significant differences were found in sensation, anterior balance, gait parameters, and Expanded Disability Status Scale (p < 0.05). An important difference was observed in walking-on-two-lines data within the groups (p < 0.05). There also was a statistically significant difference in pendular movements and dysdiadakokinesia (p < 0.05). When the posttreatment values were compared, there was no significant difference between sensation, anterior balance, gait parameters, equilibrium and nonequilibrium coordination tests, Expanded Disability Status Scale, cortical onset latency, and central conduction time of somatosensory evoked potentials and motor evoked potentials (p > 0.05). Comparison of values revealed an important difference in cortical onset-P37 peak amplitude of somatosensory evoked potentials (right limbs) in favor of the study group (p < 0.05).

CONCLUSIONS

According to our study, it was determined that physiotherapy approaches were effective to decrease the ataxia. We conclude that the combination of suitable physiotherapy techniques is effective multiple sclerosis rehabilitation.

Measurement of ataxic symptoms with a graphic tablet: standard values in controls and validity in Multiple Sclerosis patients

Aim of our study was to find a specific measure for the intensity of upper limb tremor and other ataxic symptoms in Multiple Sclerosis (MS) patients, and to establish standard values and test quality parameters. Three hundred and forty-two consecutive patients with different symptoms in the upper limbs (upper motor neuron symptoms, cerebellar upper limb ataxia, and/or sensory deficits in the upper limbs) and 140 healthy controls took part in the study. All patients and controls had to trace over a 25 cm high figure '8' on a graphic tablet, to tap with the stylus on the tablet and to perform the nine-hole-peg test (9HPT). Patients were additionally examined using clinical standard scales to classify motor dysfunctions of the upper limbs. One hundred and eighty-nine patients and 27 controls were tested twice to investigate the test reliability. Kinematic analysis of the tablet data was performed by kernel estimators, oscillatory activity by spectral analysis. Total power in the 2--10 Hz band was very specific for ataxia versus other motor symptoms. Tapping and 9HPT could well distinguish patients from controls, and patients with predominant motor neuron or cerebellar symptoms from patients with predominant sensory dysfunctions. Mean drawing error did not differ between motor and sensory dysfunctions. The test--retest reliability was similarly high for both spectral analysis and 9HPT.

Neurophysiological investigations in multiple sclerosis

The advent of magnetic resonance imaging techniques has greatly reduced the diagnostic value of neurophysiological tests, particularly evoked potentials, in multiple sclerosis patients, because of the higher sensitivity in revealing subclinical involvement of the central nervous system. Technical progress and new methods of investigating afferent and efferent nervous pathways would seem to increase the sensitivity in detecting neural dysfunction, but the 'clinical gain' is modest at best. More promising is the utilization of neurophysiological tests to quantify the severity of white matter involvement. Transversal and longitudinal studies have demonstrated good correlations between neurophysiological parameters and disability measures, indicating that a battery of neurophysiological tests could be useful in monitoring the disease evolution in single patients and as surrogate endpoints in clinical trials. Further studies are needed for a better definition of the applications of evoked potentials and other neurophysiological techniques. Finally, event-related potentials and advanced electroencephalogram techniques, such as coherence analysis, could provide useful information on the pathophysiology of cognitive dysfunction, so common in multiple sclerosis patients, and with a strong impact on the quality of life.

Sensory-motor and genito-sphincter dysfunctions in multiple sclerosis

Multiple sclerosis is a chronic demyeliniting disease of the central nervous system which is characterized by an extreme multiplicity of clinical features. Multiple sclerosis can have a profound impact on the quality of life of patients. The induced handicap varies from one patient to an other, and depends on the location of the demyeliniting lesions. Among the symptoms, sensory-motor disorders and genito-sphincter dysfunctions are some of the more disabling. Thus, up to 70% of patients suffer from urinary troubles, and 15 years after the onset of the illness, 50% of patients have difficulties for deambulation. A good knowledge of these pathologies is necessary to improve the management of patients suffering from multiple sclerosis.