Michelle Cameron

Postural Control in Multiple Sclerosis: Implications for Fall Prevention

People with multiple sclerosis (MS) often have poor postural control, which likely underlies their increased risk of falls. Based on several studies of balance and gait in MS, it appears that the primary mechanisms underlying the observed changes are slowed somatosensory conduction and impaired central integration. This review of the published research on balance, gait, and falls in people with MS demonstrates that people with MS have balance impairments characterized by increased sway in quiet stance, delayed responses to postural perturbations, and a reduced ability to move toward their limits of stability. These impairments are likely causes of falls in people with MS and are consistent with the reduced gait speed, as well as decreased stride length, cadence, and joint movement, observed in most studies of gait in MS. Based on these findings, we identify several factors that may be amenable to intervention to prevent falls in people with MS.

Imbalance in multiple sclerosis: a result of slowed spinal somatosensory conduction.

Balance problems and falls are common in people with multiple sclerosis (MS) but their cause and nature are not well understood. It is known that MS affects many areas of the central nervous system that can impact postural responses to maintain balance, including the cerebellum and the spinal cord. Cerebellar balance disorders are associated with normal latencies but reduced scaling of postural responses. We therefore examined the latency and scaling of automatic postural responses, and their relationship to somatosensory evoked potentials (SSEPs), in ten people with MS and imbalance and ten age-, sex-matched, healthy controls. The latency and scaling of postural responses to backward surface translations of five different velocities and amplitudes, and the latency of spinal and supraspinal somatosensory conduction, were examined. Subjects with MS had large, but very delayed automatic postural response latencies compared to controls (161 ± 31 ms vs. 102 ± 21 ms, p < 0.01) and these postural response latencies correlated with the latencies of their spinal SSEPs (r = 0.73, p < 0.01). Subjects with MS also had normal or excessive scaling of postural response amplitude to perturbation velocity and amplitude. Longer latency postural responses were associated with less velocity scaling and more amplitude scaling. Balance deficits in people with MS appear to be caused by slowed spinal somatosensory conduction and not by cerebellar involvement. People with MS appear to compensate for their slowed spinal somatosensory conduction by increasing the amplitude scaling and the magnitude of their postural responses.

Summary of evidence-based guideline: Complementary and alternative medicine in multiple sclerosis: Report of the Guideline Development Subcommittee of the American Academy of Neurology

Objective: To develop evidence-based recommendations for complementary and alternative medicine (CAM) in multiple sclerosis (MS). Methods: We searched the literature (1970–March 2011; March 2011−September 2013 MEDLINE search), classified articles, and linked recommendations to evidence. Results and recommendations: Clinicians might offer oral cannabis extract for spasticity symptoms and pain (excluding central neuropathic pain) (Level A). Clinicians might offer tetrahydrocannabinol for spasticity symptoms and pain (excluding central neuropathic pain) (Level B). Clinicians should counsel patients that these agents are probably ineffective for objective spasticity (short-term)/tremor (Level B) and possibly effective for spasticity and pain (long-term) (Level C). Clinicians might offer Sativex oromucosal cannabinoid spray (nabiximols) for spasticity symptoms, pain, and urinary frequency (Level B). Clinicians should counsel patients that these agents are probably ineffective for objective spasticity/urinary incontinence (Level B). Clinicians might choose not to offer these agents for tremor (Level C). Clinicians might counsel patients that magnetic therapy is probably effective for fatigue and probably ineffective for depression (Level B); fish oil is probably ineffective for relapses, disability, fatigue, MRI lesions, and quality of life (QOL) (Level B); ginkgo biloba is ineffective for cognition (Level A) and possibly effective for fatigue (Level C); reflexology is possibly effective for paresthesia (Level C); Cari Loder regimen is possibly ineffective for disability, symptoms, depression, and fatigue (Level C); and bee sting therapy is possibly ineffective for relapses, disability, fatigue, lesion burden/volume, and health-related QOL (Level C). Cannabinoids may cause adverse effects. Clinicians should exercise caution regarding standardized vs nonstandardized cannabis extracts and overall CAM quality control/nonregulation. Safety/efficacy of other CAM/CAM interaction with MS disease-modifying therapies is unknown.

Gait Abnormalities in Multiple Sclerosis: Pathogenesis, Evaluation, and Advances in Treatment

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system characterized by episodic decline in various neurologic functions. Gait dysfunction in MS is distinguished by decreased gait speed, walking endurance, step length, cadence and joint motion, as well as increased metabolic cost of walking and increased variability of gait. Standardized clinical, timed, and patient-based measures can identify MS patients with gait dysfunction, and observational gait analysis, instrumented walkways, or three-dimensional gait analysis can help determine which problem underlies their gait dysfunction to help direct effective treatment. Exercise may ameliorate all types of gait dysfunction. In addition, gait dysfunction due to weakness may be alleviated by orthoses or functional electrical stimulation; gait dysfunction due to spasticity may be relieved by oral, intrathecal, or intramuscular medications. Assistive devices and balance training may reduce gait dysfunction from imbalance, and dalfampridine may accelerate gait in people with MS who walk slowly.

Falls in people with MS—an individual data meta-analysis from studies from Australia, Sweden, United Kingdom and the United States

Background: Falls are common in people with multiple sclerosis (PwMS). Previous studies have generally included small samples and had varied methods. Objectives: The objectives of this paper are to compile fall rates across a broad range of ages and disease severity and to definitively assess the extent to which MS-associated and demographic factors influence fall rates. Methods: Individual data from studies in four countries that prospectively measured falls for three months were analyzed. We determined fall rates, prevalence of fallers (≥1 falls) and frequent fallers (≥2 falls), location and timing of falls, and fall-related demographic factors. Results: A total of 537 participants reported 1721 falls: 56% were fallers and 37% frequent fallers. Most falls occurred indoors (65%) between 6 a.m. and 6 p.m. (75%). Primary progressive MS was associated with significantly increased odds of being a faller (odds ratio (OR) 2.02; CI 1.08–3.78). Fall risk peaked at EDSS levels of 4.0 and 6.0 with significant ORs between 5.30 (2.23–12.64) and 5.10 (2.08–12.47). The fall rate was lower in women than men (relative risk (RR) 0.80; CI 0.67–0.94) and decreased with increasing age (RR 0.97 for each year, CI 0.95–0.98). Conclusion: PwMS are at high risk of falls and there are important associations between falls and MS-associated disability, gender and age.

Falls requiring medical attention among veterans with multiple sclerosis: A cohort study

The purpose of this study was to estimate the relative risk of an injurious fall requiring medical attention in veterans with multiple sclerosis (MS) compared with veterans without MS after controlling for sex, age, and healthcare use. The sample included 195,417 veterans treated at Veterans Health Administration (VHA) facilities in the Northwest United States in fiscal year 2008. We obtained information regarding MS diagnosis, injurious falls (operationalized as International Classifi cation of Diseases-9th Revision-Clinical Modification codes E880-E888), and demographic and healthcare use data from the VHA Consumer Health Information Performance Set database. Using logistic regression, we determined the adjusted odds ratio (OR) of an injurious fall to be three times higher in female veterans with MS than in female veterans without MS (OR = 3.0, 95% confidence interval [CI] = 1.6-5.5). The adjusted OR of an injurious fall for men with MS was also higher than for men without MS, but this difference was not statistically significant (OR = 1.2, 95% CI = 0.8-2.1). We recommend further studies evaluating the medical, social, and economic consequences of injurious falls, as well as interventions to prevent injurious falls, to improve the independence and quality of life of veterans and others living with MS.

The contemporary spectrum of multiple sclerosis misdiagnosis: A multicenter study

Objective: To characterize patients misdiagnosed with multiple sclerosis (MS). Methods: Neurologists at 4 academic MS centers submitted data on patients determined to have been misdiagnosed with MS. Results: Of 110 misdiagnosed patients, 51 (46%) were classified as “definite” and 59 (54%) “probable” misdiagnoses according to study definitions. Alternate diagnoses included migraine alone or in combination with other diagnoses 24 (22%), fibromyalgia 16 (15%), nonspecific or nonlocalizing neurologic symptoms with abnormal MRI 13 (12%), conversion or psychogenic disorders 12 (11%), and neuromyelitis optica spectrum disorder 7 (6%). Duration of misdiagnosis was 10 years or longer in 36 (33%) and an earlier opportunity to make a correct diagnosis was identified for 79 patients (72%). Seventy-seven (70%) received disease-modifying therapy and 34 (31%) experienced unnecessary morbidity because of misdiagnosis. Four (4%) participated in a research study of an MS therapy. Leading factors contributing to misdiagnosis were consideration of symptoms atypical for demyelinating disease, lack of corroborative objective evidence of a CNS lesion as satisfying criteria for MS attacks, and overreliance on MRI abnormalities in patients with nonspecific neurologic symptoms. Conclusions: Misdiagnosis of MS leads to unnecessary and potentially harmful risks to patients. Misinterpretation and misapplication of MS clinical and radiographic diagnostic criteria are important contemporary contributors to misdiagnosis.

Predicting Falls in People with Multiple Sclerosis: Fall History Is as Accurate as More Complex Measures

Background. Many people with MS fall, but the best method for identifying those at increased fall risk is not known. Objective. To compare how accurately fall history, questionnaires, and physical tests predict future falls and injurious falls in people with MS. Methods. 52 people with MS were asked if they had fallen in the past 2 months and the past year. Subjects were also assessed with the Activities-specific Balance Confidence, Falls Efficacy Scale-International, and Multiple Sclerosis Walking Scale-12 questionnaires, the Expanded Disability Status Scale, Timed 25-Foot Walk, and computerized dynamic posturography and recorded their falls daily for the following 6 months with calendars. The ability of baseline assessments to predict future falls was compared using receiver operator curves and logistic regression. Results. All tests individually provided similar fall prediction (area under the curve (AUC) 0.60–0.75). A fall in the past year was the best predictor of falls (AUC 0.75, sensitivity 0.89, specificity 0.56) or injurious falls (AUC 0.69, sensitivity 0.96, specificity 0.41) in the following 6 months. Conclusion. Simply asking people with MS if they have fallen in the past year predicts future falls and injurious falls as well as more complex, expensive, or time-consuming approaches.

Associations between Proprioceptive Neural Pathway Structural Connectivity and Balance in People with Multiple Sclerosis.

Mobility and balance impairments are a hallmark of multiple sclerosis (MS), affecting nearly half of patients at presentation and resulting in decreased activity and participation, falls, injuries, and reduced quality of life. A growing body of work suggests that balance impairments in people with mild MS are primarily the result of deficits in proprioception, the ability to determine body position in space in the absence of vision. A better understanding of the pathophysiology of balance disturbances in MS is needed to develop evidence-based rehabilitation approaches. The purpose of the current study was to (1) map the cortical proprioceptive pathway in vivo using diffusion-weighted imaging and (2) assess associations between proprioceptive pathway white matter microstructural integrity and performance on clinical and behavioral balance tasks. We hypothesized that people with MS (PwMS) would have reduced integrity of cerebral proprioceptive pathways, and that reduced white matter microstructure within these tracts would be strongly related to proprioceptive-based balance deficits. We found poorer balance control on proprioceptive-based tasks and reduced white matter microstructural integrity of the cortical proprioceptive tracts in PwMS compared with age-matched healthy controls (HC). Microstructural integrity of this pathway in the right hemisphere was also strongly associated with proprioceptive-based balance control in PwMS and controls. Conversely, while white matter integrity of the right hemisphere’s proprioceptive pathway was significantly correlated with overall balance performance in HC, there was no such relationship in PwMS. These results augment existing literature suggesting that balance control in PwMS may become more dependent upon (1) cerebellar-regulated proprioceptive control, (2) the vestibular system, and/or (3) the visual system.

Recent developments in multiple sclerosis therapeutics.

Multiple sclerosis, the most common neurologic disorder of young adults, is traditionally considered to be an inflammatory, autoimmune, demyelinating disease of the central nervous system. Based on this understanding, the initial therapeutic strategies were directed at immune modulation and inflammation control. These approaches, including high-dose corticosteroids for acute relapses and long-term use of parenteral interferon-β, glatiramer acetate or natalizumab for disease modification, are at best moderately effective. Growing evidence supports that, while an inflammatory pathology characterizes the early relapsing stage of multiple sclerosis, neurodegenerative pathology dominates the later progressive stage of the disease. Multiple sclerosis disease-modifying therapies currently in development attempt to specifically target the underlying pathology at each stage of the disease, while avoiding frequent self-injection. These include a variety of oral medications and monoclonal antibodies to reduce inflammation in relapsing multiple sclerosis and agents intended to promote neuroprotection and neurorepair in progressive multiple sclerosis. Although newer therapies for relapsing MS have the potential to be more effective and easier to administer than current therapies, they also carry greater risks. Effective treatments for progressive multiple sclerosis are still being sought.