Effect of a Tai Chi Chuan Slow Walking Intervention on Balance and Mobility in Individuals with Multiple Sclerosis

In people with Multiple Sclerosis (MS) balance impairments may lead to increased falls and mobility loss. In quiet stance, people with MS display greater postural sway than healthy controls. Tai Chi is a Chinese martial art that has decreased the risk of falling in frail elderly individuals (Wolf et al., 1996). The purpose of this study was to determine if a three week Tai Chi intervention would improve postural stability in people with MS. Seven participants (6F/1M, age 48.5 ± 10.8 years, height 1.66 ± 0.08m, mass 68.6 ± 19.8kg) attended nine one hour training sessions to practice two types of Tai Chi: standing meditation and slow walking. Postural stability was assessed before and after training using average center of pressure (CoP) velocity, total excursion and time to contact (TtC) for the static trials, and dual and single limb support times for the walking trials. To measure postural stability trials of quiet stance (QS), Tai Chi standing meditation with (SMA) and without arms (SM), tandem stance (TS), preferred speed walking (PW) and slow speed walking (SW) were assessed. Kinematic data recorded by a 12 camera motion capture system (Qualysis AB), and kinetic data collected from a single forceplate (AMTI) were used to compute net CoP. Because functional parameters can influence stability, strength obtained from a chair rise test and neural drive obtained from a foot tapping test were obtained. All results were assessed with paired t-tests (p.05). For SMA, average CoP velocity (p=.006) and excursions (p=.023) increased, and average TtC (p=.020) was reduced. For TS average CoP velocity (p=.06) and excursions (p=.09) trended towards decreased values, and average TtC (p=.045) increased. With the exception of increased left single limb support time (p=.009) PW and SW were not affected by the intervention. In conclusion, the increased neural drive, muscular strength, and postural stability in TS supports the idea that a three week Tai Chi intervention is effective at improving static balance in people with MS

Postural Stability is Reduced in People with Multiple Sclerosis due to Walking-imposed Fatigue

The most limiting symptoms reported by individuals with multiple sclerosis (MS) are impaired balance and symptomatic fatigue. We have reported greater postural sway and reduced stability following local muscular fatigue in individuals with MS, suggesting that these symptoms may be related. However, it is unknown whether a similar relationship exists with modest increases in fatigue resulting from an activity of daily living (ADL). Thus, the purpose of this study was to determine whether walking has a greater impact on balance during postural tasks in people with MS (PwMS) compared to those without. Seven PwMS (43±12 yrs, 6F/1M) and 10 controls (CON; 42±12 yrs, 7F/3M) performed postural tasks (quiet stance, fixed/maximal reaches) pre/post 30 minutes of treadmill walking at a range of speeds (0.6-1.4 m/s). Individuals rated their fatigue pre/post walking using a Visual Analog Scale. Kinematic data were recorded using a passive marker system (Qualysis AB) and kinetic data were recorded using two forceplates (AMTI), one under each foot. The net center of pressure was analysed using a time to contact analysis to assess postural stability. Following prolonged walking PwMS demonstrated greater reductions in stability than the CON group during the most challenging task (P=0.04), that may be related to increased fatigue (P\u3c0.0001) following walking. PwMS demonstrated greater stability than the CON group for maximal reaches (backward, P=0.009; forward, P=0.03 frontal plane only), which may be explained by reduced reach distances performed by the PwMS (backward, P=0.2; forward, P=0.008). These findings suggest that PwMS place a higher priority on stability, than maximal reach distance, which could relate to fall-related fear or specific disease-related limitations. These findings indicate that postural stability is reduced in PwMS following a common ADL, thus individuals with MS should be counseled on the increased likelihood of balance loss with heightened fatigue, even at relatively low levels

Sensorimotor Function in Progressive Multiple Sclerosis

Background: A sensitive test reflecting subtle sensorimotor changes throughout disease progression independent of mobility impairment is currently lacking in progressive multiple sclerosis. Objectives: We examined non-ambulatory measures of upper and lower extremity sensorimotor function that may reveal differences between relapsing–remitting and progressive forms of multiple sclerosis. Methods: Cutaneous sensitivity, proprioception, central motor function and mobility were assessed in 32 relapsing–remitting and 31 progressive multiple sclerosis patients and 30 non-multiple sclerosis controls. Results: Cutaneous sensation differed between relapsing–remitting and progressive multiple sclerosis at the foot and to a lesser extent the hand. Proprioception function in the upper but not the lower extremity differed between relapsing–remitting and progressive multiple sclerosis, but was different for both upper and lower extremities between multiple sclerosis patients and non-multiple sclerosis controls. Foot-tap but not hand-tap speed was slower in progressive compared to relapsing–remitting multiple sclerosis, suggestive of greater central motor function impairment in the lower extremity in progressive multiple sclerosis. In addition, the non-ambulatory sensorimotor measures were more sensitive in detecting differences between relapsing–remitting and progressive multiple sclerosis than mobility assessed with the 25-foot walk test. Conclusion: This study provides novel information about changes in sensorimotor function in progressive compared with relapsing–remitting forms of multiple sclerosis, and in particular the importance of assessing both upper and lower extremity function. Importantly, our findings showed loss of proprioceptive function in multiple sclerosis but also in progressive compared to relapsing–remitting multiple sclerosis

Gait Impairments in Persons with Multiple Sclerosis Across Preferred and Fixed Walking Speeds

Objectives: To investigate (1) whether previously observed changes in gait parameters in individuals with multiple sclerosis (MS) are the result of slower preferred walking speeds or reflect adaptations independent of gait speed; and (2) the changes in spatiotemporal features of the unstable swing phase of gait in people with MS. Design: Cross-sectional study assessing changes in gait parameters during preferred, slow (0.6m/s), medium (1.0m/s), and fast (1.4m/s) walking speeds. Setting: Gait laboratory with instrumented walkway and motion capture system. Participants: MS group with mild to moderate impairment (n_19, 16 women) with a median Expanded Disability Status Scale score of 3.75 (range, 2.5– 6), and a sex- and age-matched control group (n_19). Interventions: Not applicable. Main Outcome Measures: Gait speed, stride length, stride width, cadence, dual support time, swing time, and timing of swing foot and body/head center of mass during swing phase. Results: Individuals with MS walked at slower preferred speeds with longer dual support times compared with controls. In fixed-speed conditions, dual support times were longer and swing times were shorter in MS compared with controls. Stride width was wider for all speed conditions in the MS group. In fixed-speed conditions, the MS group positioned their head and body centers of mass closer to the anterior base of support boundary when entering the unstable equilibrium of the swing phase. Conclusions: Longer dual support time is part of a gait strategy in MS that is apparent even when controlling for the confounding effect of slower preferred speed. However, a gait strategy featuring longer dual support times may have limitations if potentially destabilizing swing dynamics exist, which especially occur at walking speeds other than preferred for people with MS

CropPol: a dynamic, open and global database on crop pollination

Seventy five percent of the world's food crops benefit from insect pollination. Hence, there has been increased interest in how global change drivers impact this critical ecosystem service. Because standardized data on crop pollination are rarely available, we are limited in our capacity to understand the variation in pollination benefits to crop yield, as well as to anticipate changes in this service, develop predictions, and inform management actions. Here, we present CropPol, a dynamic, open and global database on crop pollination. It contains measurements recorded from 202 crop studies, covering 3,394 field observations, 2,552 yield measurements (i.e. berry weight, number of fruits and kg per hectare, among others), and 47,752 insect records from 48 commercial crops distributed around the globe. CropPol comprises 32 of the 87 leading global crops and commodities that are pollinator dependent. Malus domesticais the most represented crop (32 studies), followed by Brassica napus (22 studies), Vaccinium corymbosum (13 studies), and Citrullus lanatus (12 studies). The most abundant pollinator guilds recorded are honey bees (34.22% counts), bumblebees (19.19%), flies other than Syrphidae and Bombyliidae (13.18%), other wild bees (13.13%), beetles (10.97%), Syrphidae (4.87%), and Bombyliidae (0.05%). Locations comprise 34 countries distributed among Europe (76 studies), Northern America (60), Latin America and the Caribbean (29), Asia (20), Oceania (10), and Africa (7). Sampling spans three decades and is concentrated on 2001-05 (21 studies), 2006-10 (40), 2011-15 (88), and 2016-20 (50). This is the most comprehensive open global data set on measurements of crop flower visitors, crop pollinators and pollination to date, and we encourage researchers to add more datasets to this database in the future. This data set is released for non-commercial use only

CropPol : a dynamic, open and global database on crop pollination

Seventy five percent of the world's food crops benefit from insect pollination. Hence, there has been increased interest in how global change drivers impact this critical ecosystem service. Because standardized data on crop pollination are rarely available, we are limited in our capacity to understand the variation in pollination benefits to crop yield, as well as to anticipate changes in this service, develop predictions, and inform management actions. Here, we present CropPol, a dynamic, open, and global database on crop pollination. It contains measurements recorded from 202 crop studies, covering 3,394 field observations, 2,552 yield measurements (i.e., berry mass, number of fruits, and fruit density [kg/ha], among others), and 47,752 insect records from 48 commercial crops distributed around the globe. CropPol comprises 32 of the 87 leading global crops and commodities that are pollinator dependent. Malus domestica is the most represented crop (32 studies), followed by Brassica napus (22 studies), Vaccinium corymbosum (13 studies), and Citrullus lanatus (12 studies). The most abundant pollinator guilds recorded are honey bees (34.22% counts), bumblebees (19.19%), flies other than Syrphidae and Bombyliidae (13.18%), other wild bees (13.13%), beetles (10.97%), Syrphidae (4.87%), and Bombyliidae (0.05%). Locations comprise 34 countries distributed among Europe (76 studies), North America (60), Latin America and the Caribbean (29), Asia (20), Oceania (10), and Africa (7). Sampling spans three decades and is concentrated on 2001-2005 (21 studies), 2006-2010 (40), 2011-2015 (88), and 2016-2020 (50). This is the most comprehensive open global data set on measurements of crop flower visitors, crop pollinators and pollination to date, and we encourage researchers to add more datasets to this database in the future. This data set is released for non-commercial use only. Credits should be given to this paper (i.e., proper citation), and the products generated with this database should be shared under the same license terms (CC BY-NC-SA)