Sensitivity to heat in MS patients: a factor strongly influencing symptomology--an explorative survey

Mechanisms and pharmacology of neuropathic pain in multiple sclerosis

The neuropathic pain of multiple sclerosis is quite prevalent and severely impacts quality of life. A few randomized, placebo-controlled, blinded clinical trials suggest that cannabis- and anticonvulsant-based treatments provide partial pain relief, but at the expense of adverse events. An even smaller, but emerging, number of translational studies are using rodent models of experimental autoimmune encephalomyelitis (EAE), which exhibit pain-like behaviors resembling those of Multiple sclerosis (MS) patients. These studies not only support the possible effectiveness of anticonvulsants, but also compel further clinical trials with serotonin-norepinephrine reuptake inhibitors, the immunosuppressant drug rapamycin, or drugs which interfere with glutamatergic neurotransmission. Future behavioral studies in EAE models are essential toward a new pharmacotherapy of multiple sclerosis pain.

Headache in multiple sclerosis: features and implications for disease management

The aim of this study was to investigate the variables affecting headache occurrence in patients with multiple sclerosis (MS). Seventy-two MS patients with comorbid headaches completed a 28-item questionnaire. This evaluation assessed each patient's demographics, headache description and modifying factors, social history, and impact on quality of life. Our patients reported a wide spectrum of headache presentations, characteristics, and resulting disability. We discuss the patterns in our data in the context of current hypotheses regarding headache and MS causality. In our patients, migraines with aura strongly correlated with MS exacerbations, suggesting that they might be useful as a marker for flare-up onset. Patients' pain descriptions varied based on their headache frequency, history, and relationship to MS progression. Due to the severity of headache in MS patients and resulting impact on their activities of daily living, a thorough analysis of headache presentation is warranted in such patients.

Thalamo-striato-cortical determinants to fatigue in multiple sclerosis

BACKGROUND

The aim was to explore the thalamo-striato-cortical theory of central fatigue in multiple sclerosis (MS) patients with self-reported fatigue. If the theory correctly predicted fatigue based on disruptions of the thalamo-striato-cortical network, we expected altered brain activation in this network in MS participants while performing a complex cognitive task that challenged fatigue.

METHODS

MS participants with self-reported fatigue were examined by functional magnetic resonance imaging (fMRI) during the performance of a complex working memory task. In this task, cognitive effort was challenged by a parametric design, which modeled the cerebral responses at increasing cognitive demands. In order to explore the theory of central fatigue in MS we also analyzed the cerebral responses by adding perceived fatigue scores as covariates in the analysis and by calculating the functional connectivity between regions in the thalamo-striatocortical network. The main findings were that MS participants elicited altered brain responses in the thalamo-striato-cortical network, and that brain activation in the left posterior parietal cortex and the right substantia nigra was positively correlated to perceived fatigue ratings. MS participants had stronger cortical-to-cortical and subcortical-to-subcortical connections, whereas they had weaker cortical-to-subcortical connections.

CONCLUSIONS

The findings of the present study indicate that the thalamo-striato-cortical network is involved in the pathophysiology of fatigue in MS, and provide support for the theory of central fatigue. However, due to the limited number of participants and the somewhat heterogeneous sample of MS participants, these results have to be regarded as tentative, though they might serve as a basis for future studies.

Identifying symptom co-occurrence in persons with multiple sclerosis

Patients with multiple sclerosis (MS) experience a myriad of symptoms. There is some evidence that symptoms may co-occur, or happen in particular combinations. Yet most existing studies focus on single symptoms and practitioners make a priori care decisions based on individual symptoms alone. We examined symptom co-occurrences in patients with relapsing-remitting MS (RRMS), collecting qualitative and quantitative data (mixed methods; N = 140). Content analysis revealed fatigue, heat intolerance, numbness, balance problems, and leg weakness as the most common symptoms. Factor analysis revealed the following factors: urinary, problems with balance, vision, heat, depression, and sleep. These preliminary findings indicate co-occurrence of several disabling symptoms from the overall self-report MS-Related Symptom Scale and 3-month recall. This information will guide health care professionals in developing targeted interventions and improve outcomes.

Neuropathic pain in animal models of nervous system autoimmune diseases

Neuropathic pain is a frequent chronic presentation in autoimmune diseases of the nervous system, such as multiple sclerosis (MS) and Guillain-Barre syndrome (GBS), causing significant individual disablement and suffering. Animal models of experimental autoimmune encephalomyelitis (EAE) and experimental autoimmune neuritis (EAN) mimic many aspects of MS and GBS, respectively, and are well suited to study the pathophysiology of these autoimmune diseases. However, while much attention has been devoted to curative options, research into neuropathic pain mechanisms and relief has been somewhat lacking. Recent studies have demonstrated a variety of sensory abnormalities in different EAE and EAN models, which enable investigations of behavioural changes, underlying mechanisms, and potential pharmacotherapies for neuropathic pain associated with these diseases. This review examines the symptoms, mechanisms, and clinical therapeutic options in these conditions and highlights the value of EAE and EAN animal models for the study of neuropathic pain in MS and GBS.

Work capacity and health-related quality of life among individuals with multiple sclerosis reduced by fatigue: a cross-sectional study

BACKGROUND

Among individuals diagnosed with the chronic neurologic disease, multiple sclerosis (MS), a majority suffers from fatigue, which strongly influences their every-day-life. The aim of this study was to investigate work capacity and health-related quality of life (HRQoL) in a group of MS patients and also to investigate if work capacity and HRQoL could be predicted by background factors, fatigue, heat sensitivity, cognitive dysfunction, emotional distress or degree of disability.

METHODS

A descriptive, cross-sectional, designed survey was undertaken A questionnaire was sent to 323 individuals diagnosed with MS, aged between 20 and 65 years, with physical disability on the expanded disability status score (EDSS) in the interval 0 ≥ EDSS ≤ 6.5, living in Östergötland county in eastern Sweden. Questions on background factors, occupation and work, together with the health-related quality of life short form instrument (SF-36), the fatigue severity scale (FSS), the perceived deficit questionnaire (PDQ) and the hospital anxiety depression scale (HAD) were posed. Associations between variables were analyzed using Pearson's and Spearman's correlations. Differences between groups were tested using the Chi-square test, the Mann Whitney U-test, and the Student's t-test. Predictive factors were analyzed using multiple linear and multiple logistic regression analysis.

RESULTS

Of those who completed the questionnaire (n = 257, 79.6%), 59.8% were working. Work capacity was found significantly more among men (p < 0.005), those with a higher level of education (p < 0.001), those reporting less fatigue (p < 0.001), and those having no heat sensitivity (p = 0.004). For work capacity, significant predictors were low physical disability (EDSS), low fatigue, higher level of education, male sex and lower age. Those with work capacity showed significantly higher HRQoL than those who had no work capacity (p < 0.001). Levels of fatigue, cognition and emotional distress were found to be major contributing factors for HRQoL.

CONCLUSIONS

Work capacity and HRQoL among individuals diagnosed with MS are highly influenced by fatigue which can be considered as a key symptom. Work capacity was influenced by heat-sensitivity, cognitive difficulties and emotional distress and significant predictive factors besides fatigue, were physical disability (EDSS), age, sex, and level of education. Remaining at work also gives a better HRQoL.

The use of focus groups to characterize symptoms in persons with multiple sclerosis

Multiple sclerosis is a chronic neurological disease with a myriad of symptoms. Because most work has been quantitative, it is important to capture symptoms as described by patients who experience them, using a qualitative approach. The purpose of our study was to describe and identify symptoms, with emphasis on co-occurrence, using focus groups. Three focus groups were conducted (N = 16) with relapsing-remitting multiple sclerosis patients. Common symptoms, described as both singular and co-occurring, were problems with balance, cognition, vision, and heat intolerance. These findings augment past characterizations of symptoms experienced in persons with relapsing-remitting multiple sclerosis and provide evidence for future studies.

Fatigue and heat sensitivity in patients with multiple sclerosis

OBJECTIVES

Fatigue is one of the most common and troubling symptoms of multiple sclerosis (MS), and heat is often reported as a trigger. Although it is assumed that this heat sensitivity is specific for MS, the evidence for disease specificity is limited. We studied the relationship between fatigue, heat sensitivity, and environmental temperature, and its specificity for MS.

MATERIALS AND METHODS

We compared 88 MS patients with 76 patients with ulcerative colitis (UC), another chronic auto-immune disease. As most important outcome measures, heat sensitivity, physical fatigue, mental fatigue, environmental temperature, and ambient UV-light levels were determined.

RESULTS

More patients with MS reported heat sensitivity for fatigue, compared to patients with UC (53.4% vs 35.5%, respectively, P = 0.016). However, heat-sensitive patients were equally fatigued as heat-insensitive patients. Climatological data, including day temperature and amount of ambient UV light, were not related to fatigue in both heat-sensitive and heat-insensitive patients with MS.

CONCLUSIONS

Our findings support the assumption that heat sensitivity regarding fatigue has an MS-specific component. Although patients with MS experience a relationship between environmental temperature and fatigue, objective assessment by climatological data could not confirm this.

Heat sensitive persons with multiple sclerosis are more tolerant to resistance exercise than to endurance exercise

Background:

Heat sensitivity (HS) is reported by 58% of all persons with multiple sclerosis (MS), causing symptom exacerbation possibly limiting exercise participation.

Objective:

The purpose of this study was to test the hypotheses that (a) a relationship between exercise-induced changes in core–temperature (Ctemp) and changes in symptom intensity exists, and (b) that resistance exercise (RE), as a consequence of a minor increase in core temperature, will induce a lesser worsening of symptoms than endurance exercise (EE) in HS persons with MS.

Methods:

On two separate days, 16 HS persons with MS randomly completed a session of RE and EE, or EE and RE, respectively. Testing was conducted pre, post and one hour after exercise and consisted of Visual Analogue Scale (VAS) scoring (fatigue, spasticity, pain, strength, walking and balance), the 5-time sit-to-stand (5STS), the Multiple Sclerosis Functional Composite (MSFC) and Body Sway. Composite scores describing average subjective symptom intensity (SI) and total number of symptoms (SN) were calculated from VAS scores.

Results:

Ctemp (0.9±0.4°C vs 0.3±0.1°C, p<0.001), SI (1.7±1.9 cm vs 0.6±1.5 cm, p<0.05) and SN (1.6±1.9 vs 0.6±2.1, p<0.05) increased significantly more during EE than RE. Changes in Ctemp correlated to changes in SI ( r=0.50, p<0.01). No differences were observed in 5STS, MSFC and Body Sway scores after EE when compared to RE.

Conclusion:

An exercise-induced increase in Ctemp is associated with increased number and severity of perceived symptoms in HS persons with MS. Based on these findings it is expected that HS persons with MS do tolerate RE better than EE.

Keeping cool: use of air conditioning by australians with multiple sclerosis

Despite the known difficulties many people with MS have with high ambient temperatures, there are no reported studies of air conditioning use and MS. This study systematically examined air conditioner use by Australians with MS. A short survey was sent to all participants in the Australian MS Longitudinal Study cohort with a response rate of 76% (n = 2,385). Questions included hours of air-conditioner use, areas cooled, type and age of equipment, and the personal effects of overheating. Air conditioners were used by 81.9% of respondents, with an additional 9.6% who could not afford an air conditioner. Regional and seasonal variation in air conditioning use was reported, with a national annual mean of 1,557 hours running time. 90.7% reported negative effects from overheating including increased fatigue, an increase in other MS symptoms, reduced household and social activities, and reduced work capacity. Households that include people with MS spend between 4 and 12 times more on keeping cool than average Australian households.

Sunlight is associated with decreased multiple sclerosis risk: no interaction with human leukocyte antigen-DRB1*15

BACKGROUND

  Both insufficient exposure to sunlight and vitamin D deficiency have been associated with an increased risk for multiple sclerosis (MS). An interaction between human leukocyte antigen HLA-DRB1*15 and vitamin D in MS was recently proposed. We investigated the association between previous exposure to ultraviolet radiation (UVR), vitamin D status at inclusion in the study, and MS risk including the interaction of these factors with HLA-DRB1*15.

METHODS

  A population-based case-control study involving 1013 incident cases of MS and 1194 controls was performed in Sweden during 2005-2010. Subjects were classified according to their UVR exposure habits, vitamin D status, and HLA genotypes. The associations between different sun exposure habits/vitamin D levels and MS were calculated as odds ratios (OR) with 95% confidence intervals (CI) using logistic regression. Potential interaction was evaluated by calculating the attributable proportion due to interaction.

RESULTS

  Subjects with low UVR exposure had a significantly increased risk of MS compared with those who reported the highest exposure (OR 2.2, 95% CI 1.5-3.3). Similarly, subjects who had 25-hydroxy-vitamin D levels less than 50 nM/l had an increased risk for MS (OR 1.4, 95% CI 1.2-1.7). The association between UVR exposure and MS risk persisted after adjustment for vitamin D status. There was no interaction with HLA-DRB1*15 carriage.

CONCLUSIONS

  UVR and vitamin D seem to affect MS risk in adults independently of HLA-DRB1*15 status. UVR exposure may also exert a protective effect against developing MS via other pathways than those involving vitamin D.