Profiling cognitive-motor interference in a large sample of persons with progressive multiple sclerosis and impaired processing speed: results from the CogEx study.

BACKGROUND: Performing cognitive-motor dual tasks (DTs) may result in reduced walking speed and cognitive performance. The effect in persons with progressive multiple sclerosis (pwPMS) having cognitive dysfunction is unknown. OBJECTIVE: To profile DT-performance during walking in cognitively impaired pwPMS and examine DT-performance by disability level. METHODS: Secondary analyses were conducted on baseline data from the CogEx-study. Participants, enrolled with Symbol Digit Modalities Test 1.282 standard deviations below normative value, performed a cognitive single task ([ST], alternating alphabet), motor ST (walking) and DT (both). Outcomes were number of correct answers on the alternating alphabet task, walking speed, and DT-cost (DTC: decline in performance relative to the ST). Outcomes were compared between EDSS subgroups (≤ 4, 4.5-5.5, ≥ 6). Spearman correlations were conducted between the DTCmotor with clinical measures. Adjusted significance level was 0.01. RESULTS: Overall, participants (n = 307) walked slower and had fewer correct answers on the DT versus ST (both p < 0.001), with a DTCmotor of 15.8% and DTCcognitive of 2.7%. All three subgroups walked slower during the DT versus ST, with DTCmotor different from zero (p's < 0.001). Only the EDSS ≥ 6 group had fewer correct answers on the DT versus ST (p < 0.001), but the DTCcognitive did not differ from zero for any of the groups (p ≥ 0.039). CONCLUSION: Dual tasking substantially affects walking performance in cognitively impaired pwPMS, to a similar degree for EDSS subgroups.

Mobile health applications for improving physical function, physical activity, and quality of life in stroke survivors: a systematic review.

PURPOSE: To evaluate the effectiveness of mobile health applications (mHealth apps) containing a physical training component on physical function and physical activity in stroke rehabilitation. MATERIALS AND METHODS: A systematic literature search was conducted in three databases for studies published from inception to 12 July 2022. Clinical trials including mHealth apps with a physical training component were included using outcomes of physical function and physical activity. Quality of life was extracted as a secondary outcome. RESULTS: Five RCTs, two non-RCTs, and four uncontrolled clinical trials were included with a total of 264 stroke survivors. Eleven apps were identified with a physical training component using features of gamification (six apps), exercise prescription (three apps), and physical activity (two apps). Six out of seven studies reported statistically significant improvements in physical function in favor of the experimental group, with the most robust findings for upper extremity function. For physical activity, statistically significant improvements were seen in the experimental groups. Only one study showed significant improvement in quality of life. Overall study quality was fair. CONCLUSIONS: mHealth apps containing a physical training component are promising for physical function and physical activity in stroke rehabilitation. Further research is warranted to confirm these conclusions.Implications for rehabilitationDesign content of mobile apps with a physical training component were focused on gamification, exercise prescription, and physical activityUsing mobile app-delivered therapy seem promising for improving upper extremity function in stroke rehabilitationUsing mobile apps also supported an increase of physical activity in people with strokeStudies using mobile apps should report more specifically the dosage of physical training and adherenceUsing mobile apps seems promising as an additional tool for clinical work, however, more studies are required to understand their effectiveness in stroke rehabilitation.

Do people with multiple sclerosis perceive upper limb improvements from robotic-mediated therapy? A mixed methods study.

BACKGROUND: Robot-mediated training is increasingly considered as a rehabilitation intervention targeting upper limb disability. However, experiences of such an intervention have been rarely explored in the multiple sclerosis population. This mixed methods study sought to explore the impact of an eight week upper limb robotic intervention on experiences of people with multiple sclerosis. METHODS: Eleven participants (Median EDSS- score: 6.5) with moderate to severe upper limb impairment, performed eight week robot- mediated training of the most affected arm. The training involved a virtual learning platform called I-TRAVLE with duration of 30 min per training session, twice to three times per week. Two subjective questionnaires with items from the Intrinsic Motivation Inventory (IMI) and Credibility and Expectancy Questionnaire (CEQ) were collected bi-weekly during the intervention. Approximately one month after completing the training, three focus groups were conducted. Main themes were identified using thematic analysis. RESULTS: Results from the IMI and CEQ indicated high patient satisfaction and expectation that the intervention will be beneficial for them. Two main themes were identified: (1) Effect of the intervention on impairment and activity in that participants felt that there was a positive impact of the training on strength, endurance and during activities of daily living and that it met their expectations; (2) Experiences based on system usage from the system in that participants expressed feelings of motivation and self-improvement. The participants also perceived the training as enjoyable and concluded that the use of games instigated a competitive spirit between the participants. CONCLUSIONS: Robot-mediated training could have a motivating effect and induce a general positive experience while reducing disabilities of people with multiple sclerosis.

Associations between clinical characteristics and dual task performance in Multiple Sclerosis depend on the cognitive and motor dual tasks used.

BACKGROUND: In persons with Multiple Sclerosis (pwMS) performing a simultaneous cognitive task while walking often results in slower gait. Clinical characteristics associated with reduced dual task (DT) performance are not yet entirely clear. This multi-centre study aimed to determine the relationship between clinical and demographical characteristics with dual task (DT) walking performance in pwMS during multiple DT conditions. METHODS: Nine DT conditions were analysed, consisting of combinations of three types of cognitive ('digit span', 'subtraction', 'vigilance') and three types of walking ('walk', 'walk with cup', 'walk over obstacles') conditions. Primary outcomes were DT gait speed (m/s) and motor DT cost of gait speed (DTCmotor, %). Secondary outcomes were clinical tests of physical and cognitive functioning and patient-reported and demographical outcomes. Firstly, univariate analyses and, subsequently, multivariate analyses with backward modelling, were conducted for each type of walking DT condition separately. Cognitive DT conditions were included in the models as main and as interaction effect with the secondary outcomes. RESULTS: Analysis were performed in 81 pwMS (EDSS 3.3 ± 1.0). In the final models of DTCmotor, the significant main effects were in 'walk' DT-conditions the Symbol Digit Modalities Test (SDMT), in 'cup' conditions the SDMT and Dynamic Gait Index and in 'obstacles' conditions age. For DT gait speed, main effects were found for the 2-Minute Walking Test (2MWT) and the Multiple Sclerosis Walking Scale for all walking conditions. Additionally, interactions between cognitive DT-conditions and SDMT, age and 2MWT were found. CONCLUSION: Clinical characteristics related to DT walking performance differed according to cognitive-motor DT-condition used. Still, in general, pwMS with a better mobility demonstrated higher DT gait speed, while a faster information processing speed was related to a lower DTCmotor.

Is the impact of fatigue related to walking capacity and perceived ability in persons with multiple sclerosis? A multicenter study.

BACKGROUND: The relationship between fatigue impact and walking capacity and perceived ability in patients with multiple sclerosis (MS) is inconclusive in the existing literature. A better understanding might guide new treatment avenues for fatigue and/or walking capacity in patients with MS. OBJECTIVE: To investigate the relationship between the subjective impact of fatigue and objective walking capacity as well as subjective walking ability in MS patients. METHODS: A cross-sectional multicenter study design was applied. Ambulatory MS patients (n = 189, age: 47.6 ±â€¯10.5 years; gender: 115/74 women/men; Expanded Disability Status Scale (EDSS): 4.1 ±â€¯1.8 [range: 0-6.5]) were tested at 11 sites. Objective tests of walking capacity included short walking tests (Timed 25-Foot Walk (T25FW), 10-Metre Walk Test (10mWT) at usual and fastest speed and the timed up and go (TUG)), and long walking tests (2- and 6-Minute Walk Tests (MWT). Subjective walking ability was tested applying the Multiple Sclerosis Walking Scale-12 (MSWS-12). Fatigue impact was measured by the self-reported modified fatigue impact scale (MFIS) consisting of a total score (MFIStotal) and three subscales (MFISphysical, MFIScognitive and MFISpsychosocial). Uni- and multivariate regression analysis were performed to evaluate the relation between walking and fatigue impact. RESULTS: MFIStotal was negatively related with long (6MWT, r = -0.14, p = 0.05) and short composite (TUG, r = -0.22, p = 0.003) walking measures. MFISphysical showed a significant albeit weak relationship to walking speed in all walking capacity tests (r = -0.22 to -0.33, p < .0001), which persisted in the multivariate linear regression analysis. Subjective walking ability (MSWS-12) was related to MFIStotal (r = 0.49, p < 0.0001), as well as to all other subscales of MFIS (r = 0.24-0.63, p < 0.001), showing stronger relationships than objective measures of walking. CONCLUSIONS: The physical impact of fatigue is weakly related to objective walking capacity, while general, physical, cognitive and psychosocial fatigue impact are weakly to moderately related to subjective walking ability, when analysed in a large heterogeneous sample of MS patients.

Performed and perceived walking ability in relation to the Expanded Disability Status Scale in persons with multiple sclerosis.

BACKGROUND: The severity of walking impairment in persons with multiple sclerosis (pwMS) at different levels on the expanded disability status scale (EDSS) is unclear. Furthermore, it is unclear if the EDSS is differently related to performed- and perceived walking capacity tests. AIMS: To quantify walking impairment and perceived impact of MS on walking according to EDSS scores and to examine the relations between these parameters in pwMS. METHODS: EDSS was collected by neurologists and walking was assessed by the timed 25ft walk test (T25FWT), two minute walk test (2MWT), six minute walk test (6MWT) and the 12-item MS walking scale (MSWS-12) in 474 PwMS with mild (EDSS 1-4: n=200) to moderate (EDSS 4.5-6.5: n=274) MS. Magnitude of walking impairment was calculated and related to EDSS. RESULTS: Compared to predicted values in healthy controls, walking speed was reduced by 41.5±25.8% in the 6MWT for the total MS group and by 21.8±20.2% and 55.8±19.1% in the mild and moderate MS subgroups, respectively. The EDSS score showed the strongest relationship to the 2MWT and the 6MWT in the total MS group (r=-0.76, p<0.0001), to the MSWS-12 score in the mild MS group (r=0.56, p<0.0001), and to the 2MWT in the moderate MS group (r=-0.50, p<0.0001). CONCLUSION: In pwMS (EDSS scores 1-6.5), walking speed is on average reduced by ~40% when compared to predicted values in healthy controls, and impairments are already present at early disease stages, suggesting early initiation of rehabilitation. The 2MWT and 6MWT show the strongest relationship to EDSS, but the MSWS-12 identify impairments more gradually at low EDSS scores.

Walking capacity and ability are more impaired in progressive compared to relapsing type of multiple sclerosis.

BACKGROUND: Patients with progressive multiple sclerosis (MS) have been attributed greater walking disability than relapsing-remitting MS (RRMS) patients but quantitative data on walking speed and ability are lacking. AIM: To investigate the impact of type of MS on severity of reduced walking ability and capacity taking into account age, sex, height and disease duration. DESIGN: Cross-sectional observational multi-center study SETTING: European MS centers providing either in- or out-patient services, or both. POPULATION: This study included 502 patients: 259, 162 and 81 patients showed RRMS, secondary and primary progressive MS respectively. METHODS: Walking was evaluated by T25FW, six minute walk test and MS-Walking Scale-12. Patient characteristics were compared using a one-way ANOVA, and simple and multivariate regression analysis were applied with the walking measures. RESULTS: In adjusted (sex, age, weight, height and disease duration) analyses, walking impairments were more than 20% greater in progressive types of MS compared to RRMS. There were also indications of greater walking impairment in primary compared to secondary progressive MS patients. CONCLUSION: Clinical walking impairment was larger in progressive compared to relapsing-remitting type of MS. The biological disease mechanism, being degeneration or inflammation, impacts on disability. CLINICAL REHABILITATION IMPACT: Health care professionals must be aware of different severity of walking impairment in progressive compared to relapsing type of MS, and need for intensive treatment. Also, studies must report rehabiltiation effects according to MS type.

Spatio-temporal gait parameters change differently according to speed instructions and walking history in MS patients with different ambulatory dysfunction.

BACKGROUND: Different walking capacity test formats are applied, but their impact on the gait pattern in persons with MS (pwMS) has not yet been investigated according to baseline velocity performance. OBJECTIVE: To assess, in pwMS with different ambulation dysfunction, the impact of speed instructions and previous walking tests (2 and 6min walking test; 2MWT and 6MWT) on spatiotemporal gait parameters. METHODS: 27 participants, divided in three groups based on usual gait speed (Most Limited Community Walkers; MLCW<0.82m/s, CW>1.14m/s, LCW show intermediate values), completed the 2MWT and 6MWT. Before and after each test, they walked on the GAITRite walkway system at both usual and fastest speed. Spatio-temporal gait parameters were measured and analyzed with ANOVA. RESULTS: All gait parameters in the MLCW were significantly different from other groups. In contrast to the MLCW, the LCW and CW subgroups showed greater velocity in the fastest compared to usual speed condition, associated with a significant increase in cadence and step length. After the 6MWT, small changes in cadence at usual speed and step time at fastest speed were observed in the MLCW subgroup only. No impact of the 2MWT on gait parameters was found in any group. CONCLUSIONS: The ability to accelerate was dependent on the severity of ambulatory dysfunction. Prolonged walking during the 6MWT has, in contrast to the 2MWT, some impact on gait parameters in the most disabled group only.

Cued motor imagery in patients with multiple sclerosis.

Motor imagery (MI) is a promising practice tool in neurorehabilitation. However, in patients with multiple sclerosis (MS), impairments in MI accuracy and temporal organization were found during clinical assessment, which may limit the benefits of MI practice. Therefore, we investigated whether the MI quality of MS patients could be optimized by means of external cueing. Fourteen patients with MS and 14 healthy control patients physically executed and visually imagined a goal-directed upper limb task in the presence and absence of added visual and auditory cues. MI quality was assessed by means of eye-movement registration. As main results, it was found that MS patients had significant higher eye-movement times than controls during both execution and imagery, and overestimated the to-be-imagined movement amplitude when no external information was provided during imagery. External cues, however, decreased patients' MI duration and increased the spatial accuracy of their imagined movements. In sum, our results indicate that MS patients imagine movements in a better way when they are provided with external cues during MI. These findings are important for developing rehabilitation strategies based on MI in patients with MS.

Effect of time of day on walking capacity and self-reported fatigue in persons with multiple sclerosis: a multi-center trial.

BACKGROUND: Many persons with multiple sclerosis (PwMS) report increased fatigue in the afternoon and evening compared with the morning. It is commonly accepted that physical capacity also decreases as time of day progresses, potentially influencing the outcomes of testing. OBJECTIVE: The objective of this article was to determine whether self-reported fatigue level and walking capacity are influenced by time of day in PwMS. METHODS: A total of 102 PwMS from 8 centers in 5 countries, with a diverse level of ambulatory dysfunction (Expanded Disability Status Scale [EDSS] <6.5), participated. Patients performed walking capacity tests and reported fatigue level at three different time points (morning, noon, afternoon) during 1 day. Walking capacity was measured with the 6-Minute Walk Test (6MWT) and the 10-m walk test performed at usual and fastest speed. Self-reported fatigue was measured by the Rochester Fatigue Diary (RFD). Subgroups with mild (EDSS 1.5-4.0, n = 53) and moderate (EDSS 4.5-6.5, n = 49) ambulatory dysfunction were formed, as changes during the day were hypothesized to depend on disability status. RESULTS: Subgroups had different degree of ambulatory dysfunction (p < 0.001) but reported similar fatigue levels. Although RFD scores were affected by time of day with significant differences between morning and noon/afternoon (p < 0.0001), no changes in walking capacity were found in any subgroup. Additional analyses on subgroups distinguished by diurnal change in self-reported fatigue failed to reveal analogous changes in walking capacity. CONCLUSIONS: Testing of walking capacity is unaffected by time of day, despite changes in subjective fatigue.

[Bilateral simultaneous central retinal artery occlusion revealing giant cell arteritis]. / Occlusion bilaterale et simultanee de l'artere centrale de la retine revelatrice d'une maladie de Horton.

AIM: To point out the importance of the early diagnosis of giant cell arteritis (GCA) (Horton's disease). MATERIALS AND METHODS: a case report of a sudden bilateral blindness that had revealed GCA. CASE REPORT: A 68-year old female patient with a history of elevated blood pressure and diabetes mellitus type 2, was examined in emergency for a right painful headache developed one week previously. In ophthalmological examination, her BCVA was 0.9 and P2 in both eyes. Diagnosis of Horton's disease was not initially done in spite of elevated erythrocytes sedimentation rate (ESR) at 30 mm, protein C reactive (CRP) at 19 mg/l. The patient consulted seven weeks later in emergency for a sudden bilateral blindness associated with severe headache, recent asthenia, and limping of the lower jaw. At that time, visual acuity was reduced to light perception in both eyes whereas ophthalmoscopy revealed a bilateral central retinal artery occlusion (CRAO). ESR was 74 mm and CRP 233 mg/I. Temporal artery biopsy confirmed the diagnosis of GCA. The patient was treated with systemic steroids without visual recovery. CONCLUSION: This case outlines the importance of the early diagnosis of GCA in order to make possible to start treatment before the occurrence of irreversible complications.

Keeping an eye on imagery: the role of eye movements during motor imagery training.

We recently found that spontaneous eye movements occur during motor imagery of hand movements, which are similar to those made during physical execution. In physical execution, eye movements have been shown to play an important role during training. In motor imagery practice, however, their effect remains unclear. Therefore, in the present study, we examined the role of eye movements during motor imagery practice with specific interest in the impact of task complexity and effector specificity. Thirty-six young healthy participants were tested before and after 4 days of visual motor imagery training on a Virtual Radial Fitts' task with different indices of difficulty. Training was performed with the nondominant hand only. Subjects were divided into a group that trained while spontaneous eye movements were allowed, one that kept the eyes fixed during training, and a control group. Electro-oculography and electromyography signals were monitored to guarantee task compliance during imagery. The results indicated that eye movements during imagery did not affect the temporal parameters of the trained movement. They did, however, help to achieve maximal gains in movement accuracy and efficiency. These positive effects on the spatial parameters were most pronounced during conditions with high accuracy demands and were present for both the trained and the untrained hand. These findings contribute to guidelines for optimizing training protocols based on motor imagery.

Comparison of the 2- and 6-minute walk test in multiple sclerosis.

The 6-minute walk test (6MWT) is often used to assess walking distance in multiple sclerosis (MS), but can be both time consuming for the investigator and exhausting for people with MS (pwMS). The present report compared the 6MWT scores of 40 ambulatory pwMS with their scores on the shorter 2-minute walk test (2MWT). The 2MWT estimated the 6MWT results with a mean relative error of 5% (R(2) = 0.96; p < 0.01). As the last 4-minute period of the 6MWT seems redundant, the 2MWT may be considered as a practical replacement for the 6MWT in routine clinical assessment.

Facilitating robot-assisted training in MS patients with arm paresis: a procedure to individually determine gravity compensation.

Gravity compensation (GC) of the arm is used to facilitate arm movements in conventional therapy as well as in robot-assisted rehabilitation of neurologically impaired persons. Positive effects of GC on Range of Motion (ROM) have been demonstrated in stroke. In Multiple Sclerosis (MS), research regarding this topic is lacking. Since an active participation of the patient is required for effective training, full support of the arm might not be advisable. The present study reports on the development of a procedure to measure actively the individual need for GC and to estimate the influence of GC on ROM during reaching, lifting and transporting in severely affected Persons with MS (PwMS). Ten PwMS were tested with the procedure for determination of GC. Maximal reaching movements were performed in a 3D space in three conditions: No support (NS), with GC by the HapticMaster (GC-HM) and with GC by the HapticMaster combined with a sling suspension system (GC-HMS). For the total sample, significant correlations were found between the amount of GC and clinical tests for upper limb function. In four subjects with severe arm dysfunction it was found that mean ROM is larger in the GC-HMS condition compared to the GC-HM condition, and in the GC-HM condition compared to the NS condition, suggesting positive effects of GC on active ROM in PwMS. Therefore, GC could have a positive effect on arm rehabilitation by enabling the PwMS to actively reach a larger ROM during training.

The effect of levetiracetam on tremor severity and functionality in patients with multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) intention tremor is a disabling symptom, which is difficult to treat. OBJECTIVES: To investigate the effects of levetiracetam, an antiepileptic drug, on tremor severity and related functionality in MS. METHODS: A randomized, double-blind, placebo-controlled, cross-over study examined the effects of 6 weeks of oral levetiracetam administration (starting dose=250 mg/day, maximal dose=2000 mg/day) in 18 MS patients with disabling intention tremor. Primary outcome was Fahn's Tremor Rating Scale (FTRS) A&B. Secondary outcome measures were the nine-hole peg test, patient's opinion rated with the visual analog scale, FTRS C, and an activities of daily life questionnaire and validated tremor indexes derived during the performance of a digitized spiral drawing task and a wrist step-tracking task. Repeated measures analysis of variance and Friedman tests were applied. RESULTS: In all, 14 patients completed the trial. Maximal dose intake ranged from 1000 to most commonly 2000 mg, depending on patients' tolerance level. No significant effects of levetiracetam were found for any outcome measure. Further analyses on subgroups with different tremor severity showed no differential effects. Eight patients reported adverse events such as fatigue and stomach ache. CONCLUSIONS: Levetiracetam intake of 2000 mg/day did not affect tremor severity or functionality in patients with MS.

Unsteady gaze fixation enhances the severity of MS intention tremor.

BACKGROUND: Patients with arm intention tremor due to multiple sclerosis (MS) often manifest eye movement deficits, illustrating the role of infratentorial brain in both ocular and manual movement control. Our previous study showed that both the amplitude of intention tremor and eye fixational movements were greatly enhanced after coordinated eye-hand action toward stationary targets vs during hand movements with continuous target fixation. OBJECTIVE: The present study tested, during coordinated step-tracking movements, the hypothesis that the amplitude of hand intention tremor was influenced by (unsteady) gaze fixation onto the target. METHODS: Simultaneously recorded eye and hand tracking movements were compared between 13 MS patients with intention tremor and 14 healthy controls over conditions in which the magnitude of the primary eye and hand tracking movements, as well as their ratio, were altered. RESULTS: Patients always made larger fixational eye movements around the visual targets than the controls. In the patient group, the size of fixational eye movements decreased following a reduction in the magnitude of the preceding saccadic movement, and most interestingly, was accompanied with a decrease in tremor amplitude. An alteration in the magnitude of the primary hand movement did not affect the tremor severity. CONCLUSIONS: In patients with multiple sclerosis with intention tremor, the unsteady gaze fixation on the visual targets is proportional to the magnitude of the preceding saccades, and influences the severity of intention tremor during eye-hand coordinated visuomotor tasks.

Eye-hand coordination asymmetries in manual aiming.

The authors investigated whether movement-planning and feedback-processing abilities associated with the 2 hand-hemisphere systems mediate illusion-induced biases in manual aiming and saccadic eye movements. Although participants' (N = 23) eye movements were biased in the direction expected on the basis of a typical Müller-Lyer configuration, hand movements were unaffected. Most interesting, both left- and right-handers' eye fixation onset and time to hand peak velocity were earlier when they aimed with the left hand than they were when they aimed with the right hand, regardless of the availability of vision for online movement control. They thus adapted their eye-hand coordination pattern to accommodate functional asymmetries. The authors suggest that individuals apply different movement strategies according to the abilities of the hand and the hemisphere system used to produce the same outcome.

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.

Effect of visual information on step-tracking movements in patients with intention tremor due to multiple sclerosis.

The effect of visual information on step-tracking movements was studied in 18 patients with intention tremor due to multiple sclerosis (MS) and 15 healthy controls. Parricipants performed a slow wrist step-tracking task with stationary targets under five visual feedback conditions. The display of the target and movement cues was selectively withdrawn to examine the effects of visual information on intention tremor and movement accuracy. Results showed that intention tremor was most pronounced when visual display of both target and movement cues was available. Withdrawing visual information of the limb movement reduced tremor more than withdrawing the visual display of the target cues. Both the patient and control group was less accurate when the display of limb movement was occluded. Patients, however, were more dependent on visual information of the limb movement for accurate motor performance than healthy controls. When the visual display of the limb movement was partially occluded between or near to the targets, tremor decreased without deterioration of movement accuracy.