Neuromuscular control of Lokomat guided gait:evaluation of training parameters

De Lokomat is een looprobot die is ontwikkeld voor het revalideren van lopen. Deze robot combineert een exoskelet, dat de bewegingen van de benen robotisch kan ondersteunen, met een systeem voor gewichtsondersteuning en een loopband. Het effectief en efficiënt inzetten van Lokomat therapie vereist kennis over de neuromusculaire controle van Lokomat ondersteund lopen. Daarnaast is kennis nodig over de mate waarin de drie trainingsparameters (bewegingsondersteuning, gewichtsondersteuning en loopbandsnelheid) in staat zijn om de neuromusculaire controle van lopen te beïnvloeden. Dit wordt in huidig proefschrift onderzocht bij zowel gezonde deelnemers als patiënten die een beroerte hebben gehad. De resultaten laten zien dat Lokomat ondersteund lopen wordt gekenmerkt door vaste stappatronen en lage spieractiviteit van beenspieren, in zowel gezonde lopers als patiënten die een beroerte hebben gehad. Dit zou de effectiviteit van Lokomat therapie mogelijk kunnen verminderen, aangezien actieve bijdrage en variabele patronen belangrijke componenten van motorisch leren zijn. Daarnaast beïnvloedt het exoskelet van de Lokomat het looppatroon ook als het geen bewegingsondersteuning geeft. Hiermee moet rekening gehouden worden als de bewegingsondersteuning verlaagd wordt tijdens therapie. Met betrekking tot het variëren van de trainingsparameters, is met name het verhogen van de snelheid effectief in het verhogen van spieractiviteit. Een zo hoog mogelijke snelheid tijdens Lokomat therapie wordt dan ook geadviseerd. Over het algemeen bieden de resultaten van dit proefschrift waardevolle informatie over de implicatie van Lokomat therapie in de revalidatie. Verder onderzoek en ontwikkeling van robotica moet echter worden gestimuleerd om de toepassing van looprobots in de revalidatie te verbeteren

The effect of asymmetric movement support on muscle activity during Lokomat guided gait in able-bodied individuals

BACKGROUND: To accommodate training for unilaterally affected patients (e.g. stroke), the Lokomat (a popular robotic exoskeleton-based gait trainer) provides the possibility to set the amount of movement guidance for each leg independently. Given the interlimb couplings, such asymmetrical settings may result in complex effects, in which ipsilateral activity co-depends on the amount of guidance offered to the contralateral leg. To test this idea, the effect of asymmetrical guidance on muscle activity was explored. METHODS: 15 healthy participants walked in the Lokomat at two speeds (1 and 2 km/h) and guidance levels (30% and 100%), during symmetrical (both legs receiving 30% or 100% guidance) and asymmetrical conditions (one leg receiving 30% and the other 100% guidance) resulting in eight unique conditions. Activity of the right leg was recorded from Erector Spinae, Gluteus Medius, Biceps Femoris, Semitendinosus, Vastus Medialis, Rectus Femoris, Medial Gastrocnemius and Tibialis Anterior. Statistical Parametric Mapping was used to assess whether ipsilateral muscle activity depended on guidance settings for the contralateral leg. RESULTS: Muscle output amplitude not only depended on ipsilateral guidance settings, but also on the amount of guidance provided to the contralateral leg. More specifically, when the contralateral leg received less guidance, ipsilateral activity of Gluteus Medius and Medial Gastrocnemius increased during stance. Conversely, when the contralateral leg received more guidance, ipsilateral muscle activity for these muscles decreased. These effects were specifically observed at 1 km/h, but not at 2 km/h. CONCLUSIONS: This is the first study of asymmetrical guidance on muscle activity in the Lokomat, which shows that ipsilateral activity co-depends on the amount of contralateral guidance. In therapy, these properties may be exploited e.g. to promote active contributions by the more affected leg. Therefore, the present results urge further research on the use of asymmetrical guidance in patient groups targeted by Lokomat training

Lokomat guided gait in hemiparetic stroke patients:the effects of training parameters on muscle activity and temporal symmetry

Purpose: The Lokomat is a commercially available robotic gait trainer, applied for gait rehabilitation in post-stroke hemiparetic patients. Selective and well-dosed clinical use of the Lokomat training parameters, i.e. guidance, speed and bodyweight support, requires a good understanding of how these parameters affect the neuromuscular control of post-stroke hemiparetic gait. Materials and methods: Ten stroke patients (unilateral paresis, 7 females, 64.5 ± 6.4 years, >3months post-stroke, FAC scores 2–4)) walked in the Lokomat under varying parameter settings: 50% or 100% guidance, 0.28 or 0.56m/s, 0% or 50% bodyweight support. Electromyography was recorded bilaterally from Gluteus Medius, Biceps Femoris, Vastus Lateralis, Medial Gastrocnemius, and Tibialis Anterior. Pressure sensors placed under the feet were used to determine the level of temporal gait symmetry. Results: Varying guidance and bodyweight support had little effect on muscle activity, but increasing treadmill speed led to increased activity in both the affected (Biceps Femoris, Medial Gastrocnemius, Tibialis Anterior) and unaffected leg (all muscles). The level of temporal symmetry was unaffected by the parameter settings. Conclusions: The Lokomat training parameters are generally ineffective in shaping short term muscle activity and step symmetry patients with hemiparetic stroke, as speed is the only parameter that significantly affects muscular amplitude. Trial Registration: d.n.a.IMPLICATIONS FOR REHABILITATIONThe Lokomat is a commercially available gait trainer that can be used for gait rehabilitation in post-stroke hemiparetic patients.This study shows that muscle amplitude is generally low during Lokomat guided walking, and that treadmill Speed is the main training parameter to influence muscular output in stroke patients during Lokomat walking.Varying Guidance and Bodyweight Support within a clinical relevant range barely affected muscle activity, and temporal step symmetry was unaffected by variation in any of the training parameters.Based on the findings it is advised to increase speed as early as possible during Lokomat therapy, or use other means (e.g. feedback or instructions) to stimulate active involvement of patients during training. The Lokomat is a commercially available gait trainer that can be used for gait rehabilitation in post-stroke hemiparetic patients. This study shows that muscle amplitude is generally low during Lokomat guided walking, and that treadmill Speed is the main training parameter to influence muscular output in stroke patients during Lokomat walking. Varying Guidance and Bodyweight Support within a clinical relevant range barely affected muscle activity, and temporal step symmetry was unaffected by variation in any of the training parameters. Based on the findings it is advised to increase speed as early as possible during Lokomat therapy, or use other means (e.g. feedback or instructions) to stimulate active involvement of patients during training.</p

Do rehabilitation patients with chronic low back pain meet World Health Organisation's recommended physical activity levels?

Purpose: Primary: to analyse the time that patients with chronic low back pain (CLBP) admitted to pain rehabilitation spent on moderate to vigorous physical activity (MVPA) and compare this to the WHO recommen-dations. Secondary: to explore factors that might differentiate between those who do and do not meet the recommendations. Materials and methods: A Cross-sectional study embedded in secondary interdisciplinary rehabilitation of adults with CLBP. PA was measured with a tri-axial accelerometer for 1 week during admission phase. Time spent in each PA level was calculated. MVPA was also analysed in >= 10 min bouts. Results: Complete datasets of 4-6 days recorded accelerometery of n = 46 patients were analysed. Time spent in MVPA was on average 6.0% per day. MVPA per day in >= 10-min bouts occurred on average 0.8 times per day (sd = 0.9; min-max 0-4). Percentage of patients meeting the recommended level of MVPA was 21.7% (10/46) and 84.8% (39/46) for the 2010 and 2020 recommendations, respectively. Most demographic and clinical variables did not seem to differentiate between those who met the WHO recommendations, and those who did not. Conclusion: The minority of the patients (22%) met the WHO recommended MVPA level of 2010. The more lenient recommendation of 2020 was met by 85%

Differences in muscle activity and temporal step parameters between Lokomat guided walking and treadmill walking in post-stroke hemiparetic patients and healthy walkers

Background: The Lokomat is a robotic exoskeleton that can be used to train gait function in hemiparetic stroke. To purposefully employ the Lokomat for training, it is important to understand (1) how Lokomat guided walking affects muscle activity following stroke and how these effects differ between patients and healthy walkers, (2) how abnormalities in the muscle activity of patients are modulated through Lokomat guided gait, and (3) how temporal step characteristics of patients were modulated during Lokomat guided walking. Methods: Ten hemiparetic stroke patients (> 3 months post-stroke) and ten healthy age-matched controls walked on the treadmill and in the Lokomat (guidance force 50%, no bodyweight support) at matched speeds (0.56 m/s). Electromyography was used to record the activity of Gluteus Medius, Biceps Femoris, Vastus Lateralis, Medial Gastrocnemius and Tibialis Anterior, bilaterally in patients and of the dominant leg in healthy walkers. Pressure sensors placed in the footwear were used to determine relative durations of the first double support and the single support phases. Results: Overall, Lokomat guided walking was associated with a general lowering of muscle activity compared to treadmill walking, in patients as well as healthy walkers. The nature of these effects differed between groups for specific muscles, in that reductions in patients were larger if muscles were overly active during treadmill walking (unaffected Biceps Femoris and Gluteus Medius, affected Biceps Femoris and Vastus Lateralis), and smaller if activity was already abnormally low (affected Medial Gastrocnemius). Also, Lokomat guided walking was associated with a decrease in asymmetry in the relative duration of the single support phase. Conclusions: In stroke patients, Lokomat guided walking results in a general reduction of muscle activity, that affects epochs of overactivity and epochs of reduced activity in a similar fashion. These findings should be taken into account when considering the clinical potential of the Lokomat training environment in stroke, and may inform further developments in the design of robotic gait trainers

SPSS data files representing Amplitude normalized EMG data

The data include 6 SPSS (*.sav) data files that contain the amplitude normalized EMG amplitudes for four phases of the gait cycle (first double support phase (DS1), the single support phase (SS), the second doiuble support phase (DS2), and the swing phase (SW)) for each of the six muscles that were assessed (Erector Spinae (ES), Gluteus Medius (GM), Biceps Femoris (BF), Vastud Lateralis (VL), Medial Gastrocnemius (MG), and Tibilis Anterior (TA)

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Data from: The combined effects of body weight support and gait speed on gait related muscle activity: a comparison between walking in the Lokomat exoskeleton and regular treadmill walking

The data include 6 SPSS (*.sav) data files that contain the amplitude normalized EMG amplitudes for four phases of the gait cycle (first double support phase (DS1), the single support phase (SS), the second doiuble support phase (DS2), and the swing phase (SW)) for each of the six muscles that were assessed (Erector Spinae (ES), Gluteus Medius (GM), Biceps Femoris (BF), Vastud Lateralis (VL), Medial Gastrocnemius (MG), and Tibilis Anterior (TA)