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A higher level of education was correlated with less severe motor impairment in Parkinson's Disease (PD). Nevertheless, there is limited evidence on the relationship between cognitive reserve and motor performance in complex situations in PD. To investigate the association between cognitive reserve and the dual-task gait effect in PD. Additionally, we examined the relationship between executive function, clinical and sociodemographic variables and, dual-task gait effects. We conducted a cross-sectional study with 44 PD participants. We evaluated dual-task effect on cadence, stride length, and gait velocity. Dual-task effects were correlated with neurophysiological factors, including cognitive reserve (Cognitive Reserve Index Questionnaire), overall cognitive performance of executive functions, a specific executive function domain (Trail Making Test), and the global cognitive status (Montreal Cognitive Assessment and Mini-Mental State Examination). Age, gender, and disease severity were considered as variables to be examined for correlation. We found that cognitive reserve did not influence gait performance under dual-task conditions in this sample. However, executive functions, age, and disease severity were associated with the dual-task effect on gait. The overall cognitive performance with respect to the Trail Making Test showed an inverse relationship in the dual-task gait effect on cadence. Our study's findings have important implications for understanding the association between executive functions, age, and disease severity with the dual-task effect on gait in PD. Pre-life factors, such as education, occupation, and leisure activity, did not contribute to coping with complex gait situations in PD.
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Reserva Cognitiva , Função Executiva , Doença de Parkinson , Humanos , Doença de Parkinson/fisiopatologia , Doença de Parkinson/complicações , Masculino , Feminino , Função Executiva/fisiologia , Reserva Cognitiva/fisiologia , Idoso , Estudos Transversais , Pessoa de Meia-Idade , Desempenho Psicomotor/fisiologia , Marcha/fisiologia , Transtornos Neurológicos da Marcha/fisiopatologia , Transtornos Neurológicos da Marcha/etiologia , Testes NeuropsicológicosRESUMO
PURPOSE: The aim of this study was to explore the interday reliability of mechanical variables obtained from the horizontal and vertical force-velocity (FV) profiles in adolescent female basketball players. If found to be reliable, the associations between FV parameters (theoretical maximal force, velocity, and power), squat jump (SJ) height, 30-m sprint, and change of direction (COD) times were evaluated. METHODS: After familiarization, SJ against incremental loads, 30-m sprint, and 505-COD tests were obtained twice in 36 adolescent female basketball players (age = 15.4 [1.2] y). RESULTS: Reliability for vertical FV parameters was unacceptable, whereas 505-COD times and FV horizontal parameters (except for theoretical maximal power) showed a moderate to high reliability. 505-COD time was correlated with FV horizontal parameters (range: r = -.821, -.451), and a large association was observed with both SJ height (r = -.678, -.600) and 30-m sprint time (r = .813, .858). CONCLUSIONS: Due to low levels of strength, our athletes were not adequately prepared to obtain a reliable vertical FV profile. Practitioners can expect acceptable reliability of the horizontal FV profile. Given the association between COD performance and SJ height and 30-m sprint time, we encouraged practitioners with limited equipment at their disposal to use COD and/or 30-m sprint tests.
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Treadmill walking is considered a useful therapeutic tool for improving gait in Parkinson's disease (PD) patients. The study investigated the role of top-down, frontal-parietal versus bottom-up parietal-frontal networks, during over-ground and treadmill walking in PD and control subjects, using functional connectivity. To this end, EEG was recorded simultaneously, during a ten-minute period of continuous walking either over-ground or on a treadmill, in thirteen PD patients and thirteen age-matched controls. We evaluated EEG directed connectivity, using phase transfer entropy in three frequency bands: theta, alpha and beta. PD patients showed increased top-down connectivity during over-ground compared with treadmill walking, in the beta frequency range. Control subjects showed no significant differences in connectivity between the two walking conditions. Our results suggest that in PD patients, OG walking was associated with increased allocation of attentional resources, compared with that on the TL. These functional connectivity modulations may shed further light on the mechanisms underlying treadmill versus overground walking in PD.
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Doença de Parkinson , Humanos , Caminhada , Marcha , Teste de EsforçoRESUMO
The objective of this pilot study was to evaluate the effects of dual-task training implemented by mobile health technology on performance on motor and dual-task tests in subjects with dementia. Nineteen subjects with a medical diagnosis of dementia were assigned to an experimental group (EG, n = 12) or control group (CG, n = 7). The EG participated in 24 sessions (3/week) of a homebase dual-task exercises program, in addition to their ongoing cognitive and physiotherapy treatment. The training program was implemented individually in the patient's home by caregivers or relatives through electronic devices controlled by a mobile application. Before (Pre) and after (Post) the program, performance on motor and motor/cognitive (dual-task) tests were evaluated. Motor evaluation included gait at preferred and maximal speed, the Up and Go, and the Handgrip Strength test. Dual-task tests included gait with subtraction 3 s from 100 and naming animals (verbal fluency). The CG only performed the evaluations in addition to their cognitive and physiotherapy treatment. The statistical analysis (ANOVA Group*Test) showed a statically significant improvement for both dual-task tests in the EG after the training program, while the CG showed an impairment in the verbal fluency test. Conclusion: the implementation of a home exercise program carried out with mobile technology in people with dementia is feasible and positively affects their performance on dual tasks.
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Demência , Força da Mão , Humanos , Projetos Piloto , Marcha , Terapia por Exercício , Demência/terapiaRESUMO
The aim of the present cross-sectional study was to determine if chronic rock climbing and climbing-specific resistance training (RT) would modify the reticulospinal tract (RST) efficacy. Sixteen healthy, elite level climbers (CL; n = 16, 5 F; 29.8 ± 6.7 years) with 12 ± 7 years of climbing and climbing-specific RT experience and 15 healthy recreationally active participants (CON; n = 15, 4 F; 24.6 ± 5.9 years), volunteered for the study. We quantified RST efficacy by comparing the effects of a startle stimulus over reaction time (Rtime ) and measured rate of force development (RFD) and surface electromyography (sEMG) in representative muscles during powerful hand grip contractions. Both groups performed two Rtime tasks while performing rapid, powerful gripping with the right hand (Task 1) or during 3-s-long maximal voluntary right hand grip contractions in response to an imperative visual signal alone (V), or combined with a auditory-non startle stimulus (A) or/and startling auditory stimulus (S). We also tested the reproducibility of these responses on two separate days in CON. Intersession reliability ranged from 0.34 to 0.96 for all variables. The CL versus CON was 37% stronger (p = 0.003). The S stimulus decreased Rtime and increased RFD and sEMG in both groups during both tasks (all p < 0.001). Rtime was similar between groups in all conditions. However, CL had a greater RFD from 50 to 100 ms compared with CON only after the S stimulus in both tasks (p < 0.05, d = 0.85-0.96). The data tentatively suggest that chronic rock climbing and climbing-specific RT might improve RST efficacy, by increasing RST input to the α-motoneurons.
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Força da Mão , Montanhismo , Humanos , Reprodutibilidade dos Testes , Força da Mão/fisiologia , Músculo Esquelético/fisiologia , Dedos/fisiologia , Estudos Transversais , Montanhismo/fisiologiaRESUMO
OBJECTIVES: The main aim of this study was to determine the effects of set configuration during five weeks of unilateral knee extension resistance training on untrained knee extensors performance. METHODS: Thirty-five subjects were randomly assigned to traditional training (TTG; n=14), rest-redistribution (RRG; n=10) and control group (CON; n=11). TTG and RRG groups trained the dominant knee extensors twice a week with the 10-repetition maximum (RM) load. TTG performed four sets of eight repetitions with three min-rest between sets and RRG 32 repetitions with 17.4 seconds of rest between each one. Before and after interventions, anthropometry, muscle thickness (MT), pennation angle (PA), 1RM, number of repetitions with 10RM pretest load (N10RM), maximum propulsive power (MPP) and maximum voluntary isometric contraction (MVIC) were measured. RESULTS: 1RM of the untrained leg increased only in the TTG group (p<0.001, 10.3% compared with Pre-test). 1RM, MPP and N10RM increased in the trained leg in both TTG (p<0.001) and RRG (p<0.001). No changes occurred in MT or PA. CONCLUSIONS: These results suggest that, when it is not possible to perform bilateral exercises (e.g., leg injury), traditional set configurations should be recommended to improve maximal voluntary force in the untrained leg.
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Terapia por Exercício , Treinamento Resistido , Humanos , Exercício Físico , Articulação do Joelho , AntropometriaRESUMO
Background: Maximal aerobic speed (MAS) is a useful parameter to assess aerobic capacity and estimate training intensity in middle- and long-distance runners. However, whether middle- and long-distance runners reach different levels of MAS compared to other endurance athletes with similar VÌO2max has not been previously studied. Therefore, we aimed to compare VÌO2max, MAS and spatiotemporal parameters between sub-elite middle- and long-distance runners (n = 6) and endurance non-runners (n = 6). In addition, we aimed to compare the maximal blood lactate concentration [BLa] experienced by participants after conducting these tests. Methods: Telemetric portable respiratory gas analysis, contact and flight time, and stride length and rate were measured using a 5-m contact platform during an incremental test at a synthetic athletics track. VÌO2, heart rate, respiratory quotient values in any 15 s average period during the test were measured. [BLa] was analyzed after the test . Running spatiotemporal parameters were recorded at the last two steps of each 400 m lap. A coefficient of variation (%CV) was calculated for each spatiotemporal variable in each participant from 8 km h-1 onwards. Results: Whereas runners reported faster MAS (21.0 vs. 18.2 km h-1) than non-runners (p = 0.0001, ES = 3.0), no differences were found for VÌO2max and maximum blood lactate concentration during the running tests (p > 0.05). While significant increases in flight time and stride length and frequency (p < 0.001, 0.52 ≤ η p 2 ≤ 0.8) were observed throughout the tests, decreases in contact time (p < 0.001, η p 2 = 0 . 9 ) were reported. Runners displayed a greater %CV (p = 0.015) in stride length than non-runners. We conclude that middle- and long-distance runners can achieve a faster MAS compared to non-running endurance athletes despite exhibiting a similar VÌO2max. This superior performance may be associated to a greater mechanical efficiency. Overall, runners displayed a greater ability to modify stride length to achieve fast speeds, which may be related to a more mechanically efficient pattern of spatiotemporal parameters than non-runners.
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Consumo de Oxigênio , Resistência Física , Humanos , Resistência Física/fisiologia , Consumo de Oxigênio/fisiologia , Testes de Função Respiratória , Atletas , LactatosRESUMO
Anodal transcranial direct current stimulation (tDCS) can enhance the retention of a previously practiced motor skill. However, the effects of tDCS on the performance of the choice reaction time task are not fully understood. We examined the effects of anodal tDCS over the left primary motor cortex (M1) on the retention of a 4-choice visual-motor reaction time task (4-ChRT). Right-handed healthy participants (n = 100) were randomly assigned to five groups: three groups received anodal tDCS: before (tDCSbefore), during (tDCSduring), or after (tDCSafter) motor practice. In addition, there were two control groups: with (CONmp) and without (CON) motor practice. We evaluated the speed and precision of the 4-ChRT task before (PRE), during, and 24 h (POST) after the interventions. All groups, including the non-stimulation (CONmp) and non-practice groups (CON), improved (p < 0.05) motor retention (Δ4-ChRT: 35.8 ± 36.0 ms). These findings suggest that the tDCS effects over M1 may differ for serial versus choice RT tasks, perhaps due to the different brain areas involved in each motor task.
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Córtex Motor , Estimulação Transcraniana por Corrente Contínua , Humanos , Aprendizagem/fisiologia , Córtex Motor/fisiologia , Destreza Motora/fisiologia , Tempo de Reação/fisiologiaRESUMO
BACKGROUND: Despite the frequent use of the Timed Up and Go (TUG) test in clinical trials, evaluation of longitudinal test-retest reliability is generally lacking and still inconclusive for patients with Parkinson's disease (PD). OBJECTIVE: We aimed to further investigate long-term reliability and sensitivity of the TUG test among this population. Furthermore, we explored alternative assessment strategies of the test aimed at elucidating whether the inclusion or combination of timed trials may have potential implications on outcome measure. METHODS: Relative and absolute reliability of the TUG performance were obtained in forty-three subjects with PD over three timed trials in two different testing sessions separated by a two-months period. RESULTS: Our results reported excellent intra-session and moderate inter-session reliability coefficients. The use of different assessment strategies of the TUG was found to have an important impact on outcome measure, highlighting the averaging of several timed trials in each testing session as a recommended alternative to minimize measurement error and increase reliability in longitudinal assessments. Nevertheless, beyond acceptable reliability, poor trial-to-trial stability of the measure appears to exist, since the ranges of expected variability upon retesting were wide and the incidence of spurious statistical effects was not negligible, especially in longitudinal repeated testing. CONCLUSION: Limitations may exist in the interpretation of the TUG outputs as part of longitudinal assessments aimed at evaluating treatment effectiveness in PD population. Researchers and practitioners should be aware of these concerns to prevent possible misrepresentations of functional ability in patients for a particular intervention.
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Doença de Parkinson , Equilíbrio Postural , Atividades Cotidianas , Humanos , Doença de Parkinson/diagnóstico , Doença de Parkinson/fisiopatologia , Reprodutibilidade dos Testes , Estudos de Tempo e MovimentoRESUMO
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that may improve motor learning. However, the long-term effects of tDCS have not been explored, and the ecological validity of the evaluated tasks was limited. To determine whether 20 sessions of tDCS over the primary motor cortex (M1) would enhance the performance of a complex life motor skill, i.e., typing, in healthy young adults. Healthy young adults (nâ¯=â¯60) were semi-randomly assigned to three groups: the tDCS group (nâ¯=â¯20) received anodal tDCS over M1; the SHAM group (nâ¯=â¯20) received sham tDCS, both while performing a typing task; and the Control group (CON, nâ¯=â¯20) only performed the typing task. Typing speed and errors at maximum (mTT) and submaximal (iTT) speeds were measured before training, and after 10 and 20 sessions of tDCS. Every subject increased maximum typing speed after 10 and 20 tDCS sessions, with no significant differences (pâ¯>â¯0.05) between the groups. The number of errors at submaximal rates decreased significantly (pâ¯<â¯0.05) by 4% after 10 tDCS sessions compared with the 3% increase in the SHAM and the 2% increase in the CON groups. Between the 10th and 20th tDCS sessions, the number of typing errors increased significantly in all groups. While anodal tDCS reduced typing errors marginally, such performance-enhancing effects plateaued after 10 sessions without any further improvements in typing speed. These findings suggest that long-term tDCS may not have functionally relevant effects on healthy young adults' typing performance.
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Córtex Motor , Estimulação Transcraniana por Corrente Contínua , Encéfalo , Eletrodos , Humanos , Destreza Motora , Adulto JovemRESUMO
Physical inactivity is a major concern and poor adherence to exercise programs is often reported. The aim of this paper was to systematically review published reviews on the study of adherence to physical exercise in chronic patients and older adults and to identify those adherence-related key factors more frequently suggested by reviews for that population. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Results were classified considering the target population and participants' characteristics to identify the most repeated factors obtained for each condition. Fifty-five articles were finally included. Fourteen key factors were identified as relevant to increase adherence to physical exercise by at least ten reviews: (a) characteristics of the exercise program, (b) involvement of professionals from different disciplines, (c) supervision, (d) technology, (e) initial exploration of participant's characteristics, barriers, and facilitators, (f) participants education, adequate expectations and knowledge about risks and benefits, (g) enjoyment and absence of unpleasant experiences, (h) integration in daily living, (i) social support and relatedness, (j) communication and feedback, (k) available progress information and monitoring, (l) self-efficacy and competence, (m) participant's active role and (n) goal setting. Therefore, adherence to physical exercise is affected by several variables that can be controlled and modified by researchers and professionals.
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Exercício Físico , Cooperação do Paciente , Idoso , Doença Crônica , Terapia por Exercício , Humanos , Literatura de Revisão como Assunto , Comportamento SedentárioRESUMO
ABSTRACT: Fariñas, J, Mayo, X, Giraldez-García, MA, Carballeira, E, Fernandez-Del-Olmo, M, Rial-Vazquez, J, Kingsley, JD, and Iglesias-Soler, E. Set configuration in strength training programs modulates the cross education phenomenon. J Strength Cond Res 35(9): 2414-2420, 2021-This study aimed to compare the strength gains in the nontrained arm after 2 independent unilateral training programs differing in the set configuration. Thirty-five subjects were randomly assigned to 3 groups: traditional training (TT; n = 12), cluster training (CT; n = 11), or control (CON; n = 12). The experimental groups performed a 5-week training program of a unilateral biceps curl exercise with the dominant limb using the 10 repetition maximum (10RM) load. Traditional training performed 5 sets of 6 repetitions and 135 seconds of rest between sets. Cluster training completed 30 repetitions with 18.5 seconds of rest between each repetition. Anthropometry (ANT), muscle thickness (MT), 1RM, the number of repetitions with 10RM (n10RM), and isometric maximal voluntary contraction (MVC) were measured before and after the intervention. Regarding the nontrained arm, TT improved 1RM (7.3%, p < 0.001). No changes were observed in CT. Regarding the trained arm, TT improved 1RM (9.1%, p < 0.001), n10RM (p = 0.005), and MVC (p = 0.011), whereas CT only showed a trend for improvement of 1RM (3.4%, p = 0.052). These results suggest that when total volume and repetition-to-rest ratio are equated, a more fatiguing set configuration causes a higher effect on the non-trained limb.
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Treinamento Resistido , Humanos , Contração Isométrica , Força Muscular , Músculo Esquelético , DescansoRESUMO
Repetitive, monotonic, and effortful voluntary muscle contractions performed for just a few weeks, i.e., resistance training, can substantially increase maximal voluntary force in the practiced task and can also increase gross motor performance. The increase in motor performance is often accompanied by neuroplastic adaptations in the central nervous system. While historical data assigned functional relevance to such adaptations induced by resistance training, this claim has not yet been systematically and critically examined in the context of motor performance across the lifespan in health and disease. A review of muscle activation, brain and peripheral nerve stimulation, and imaging data revealed that increases in motor performance and neuroplasticity tend to be uncoupled, making a mechanistic link between neuroplasticity and motor performance inconclusive. We recommend new approaches, including causal mediation analytical and hypothesis-driven models to substantiate the functional relevance of resistance training-induced neuroplasticity in the improvements of gross motor function across the lifespan in health and disease.
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Plasticidade Neuronal , Treinamento Resistido , Eletromiografia , Potencial Evocado Motor , Humanos , Contração Isométrica , Músculo Esquelético , Estimulação Magnética TranscranianaRESUMO
BACKGROUND: The reviewed studies on center of pressure (COP) displacement in Parkinson's disease (PD) subjects show important methodological differences and contradictory results with regard to healthy subjects. The dual-task paradigm method has been used to examine cognitive prioritization strategies to control concurrent postural and cognitive tasks. The motor requirements, such as pronouncing words, involved in the cognitive tasks used in double-task conditions could be related to the heterogeneity of the results. RESEARCH OBJECTIVE: To compare postural sway and cognitive performance in subjects with PD and controls using a dual-task paradigm with a cognitive task free of motor demands. We tried to examine the prioritization strategy of PD patients regarding healthy adults to control for concurrent postural and cognitive tasks. MATERIALS AND METHODS: 25 subjects with PD and 20 healthy controls carried out a postural task under both single-task and dual-task conditions. The postural task was to stand as still as possible, with eyes first open and then closed. The dual-task condition added a concurrent cognitive task based on phoneme monitoring. COP displacement variables and cognitive performance were compared between the groups and within-subject factors were also examined. RESULTS: PD participants showed higher COP displacement results than the controls. All participants shortened the mean sway radius in dual-task conditions compared with single-task conditions; only healthy subjects presented less transversal COP sway in dual-task conditions than in single-task conditions. The cognitive performance of PD patients on a phoneme monitoring task worsened when they carried it out while maintaining balance in a standing position compared to sitting. The opposite effect occurred in control subjects. CONCLUSION: This study confirms the negative influence of Parkinson's disease on the control of standing stability, increasing the COP sway amplitude. The attentional demands of a postural task, such as standing balance, may be greater in PD patients than in healthy subjects. This would affect the performance of patients during dual-task conditions to be able to control a postural task while performing other cognitive tasks. In these conditions, cognitive performance would be negatively affected. These results suggest that subjects with PD, at least during initial disease stages, prioritize postural control over other concurrent tasks, as is also seen in healthy subjects.
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Despite the growing interest in the use of transcranial direct current stimulation (tDCS) for the modulation of human cognitive function, there are contradictory findings regarding the cognitive benefits of this technique. Inter-individual response variability to tDCS may play a significant role. We explored the effects of anodal versus sham tDCS over the left prefrontal cortex (LPFC) on working memory performance, taking into account the inter-individual variability. Twenty-nine healthy volunteers received an 'offline' anodal tDCS (1.5â¯mA, 15â¯min) to the left prefrontal cortex (F3 electrode site) in an intra-individual, cross-over, sham-controlled experimental design. n-back and Sternberg task performance was assessed before (baseline), immediately after tDCS administration (T1) and 5â¯min post-T1 (T2). We applied an integrative clustering approach to characterize both the group and individual responses to tDCS, as well as identifying naturally occurring subgroups that may be present within the total sample. Anodal tDCS failed to improve working memory performance in the total sample. Cluster analysis identified a subgroup of 'responders' who significantly improved their performance after anodal (vs. sham) stimulation, although not to a greater extent than the best baseline or sham condition. The proportion of 'responders' ranged from 15% to 59% across task conditions and behavioral outputs. Our findings show a high inter-individual variability of the tDCS response, suggesting that the use of tCDS may not be an effective tool to improve working memory performance in healthy subjects. We propose that the use of clustering methods is more suitable in identifying 'responders' and for evaluating the efficacy of this technique.
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Estimulação Transcraniana por Corrente Contínua , Análise por Conglomerados , Cognição , Humanos , Memória de Curto Prazo , Córtex Pré-FrontalRESUMO
PURPOSE: This study aimed to explore the acute effect of transcranial direct current stimulation (tDCS) on the force-velocity relationship, strength training volume, movement velocity, and ratings of perceived exertion. METHODS: Fourteen healthy men (age 22.8 ± 3.0 years) were randomly stimulated over the dorsolateral prefrontal cortex with either ANODAL, CATHODAL or SHAM tDCS for 15 min at 2 mA. The one-repetition maximum (1RM) and force-velocity relationship parameters were evaluated during the bench press exercise before and after receiving the tDCS. Subsequently, participants completed a resistance training session consisting of sets of five repetitions with 1 min of inter-set rest against the 75%1RM until failure. RESULTS: No significant changes were observed in the 1RM or in the force-velocity relationship parameters (p ≥ 0.377). The number of repetitions was higher for the ANODAL compared to the CATHODAL (p = 0.025; ES = 0.37) and SHAM (p = 0.009; ES = 0.47) conditions. The reductions of movement velocity across sets were lower for the ANODAL than for the CATHODAL and SHAM condition (p = 0.014). RPE values were lower for the ANODAL compared to the CATHODAL (p = 0.119; ES = 0.33) and SHAM (p = 0.150; ES = 0.44) conditions. No significant differences between the CATHODAL and SHAM conditions were observed for any variable. CONCLUSION: The application of ANODAL tDCS before a resistance training session increased training volume, enabled the maintenance of higher movement velocities, and reduced RPE values. These results suggest that tDCS could be an effective method to enhance resistance-training performance.
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Tolerância ao Exercício , Treinamento Resistido/métodos , Estimulação Transcraniana por Corrente Contínua/métodos , Adulto , Humanos , Masculino , Movimento , Contração Muscular , Córtex Pré-Frontal/fisiologiaRESUMO
BACKGROUND: The interest in the use of anodal transcranial direct current stimulation (tDCS) for the enhancement of cognitive functioning has increased significantly in recent years. However, the efficacy of this technique remains to be established. OBJECTIVE: The current study explored the effects of anodal vs. sham tDCS over the left dorsolateral prefrontal cortex (DLPFC) during the performance of the digit span backwards task. METHODS: 30 healthy participants received 'offline' anodal tDCS (1.5â¯mA, 15â¯min) to the left DLPFC in an intra-individual, cross-over, sham-controlled experimental design. Memory span performance was assessed before (baseline), immediately after tDCS administration (T1) and 10â¯min post-T1 (T2). We applied cluster analysis in order to characterize individual responses to tDCS, and in order to identify naturally occurring subgroups that may be present. RESULTS: Analysis of all the subjects showed that anodal tDCS failed to improve memory span performance. Cluster analysis revealed the presence of a subgroup of 'responders' that significantly improved their performance after anodal (vs. sham) tDCS in T1 (47%) and T2 (46%). However, there was no significant improvement in performance after anodal tDCS compared to the best baseline performance. CONCLUSION: Our findings suggest that tDCS does not improve memory span performance and highlights the need for better ways to optimize methodological approaches in order to account for inter-individual variability and accurately assess the evidential value of tDCS-linked cognitive outcomes.
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Memória de Curto Prazo/fisiologia , Córtex Pré-Frontal/fisiologia , Estimulação Transcraniana por Corrente Contínua , Adulto , Análise por Conglomerados , Cognição , Estudos Cross-Over , Feminino , Humanos , Masculino , Adulto JovemRESUMO
BACKGROUND: The use of the treadmill as a gait rehabilitation tool has provided novel options for treatment of gait impairments in Parkinson's Disease (PD). However, the neural mechanisms underlying these therapeutic effects in PD remain unknown and whether any therapeutic effects from treadmill training can be reproduced on overground walking. OBJECTIVE: To examine the immediate short-term effects of a single session of treadmill and overground walking on gait, spinal and corticospinal parameters in PD.METHODSPD participants (Nâ=â15) were evaluated in two separate sessions under two walking conditions: walking over a treadmill and walking overground. Overground walking performance, the Soleus H-reflex, Reciprocal Ia-Inhibition, Intracortical Facilitation (ICF) and Short Intracortical Inhibition (SICI), were evaluated before and after each condition. RESULTS: Gait speed and stride length improved in post-treadmill compared with pre-treadmill. No significant changes in these gait parameters were found for the pre vs. post-overground condition. ICF values and Hmax/Mmax ratio decreased after, compared with before, the two walking conditions. CONCLUSIONS: Treadmill walking, but not overground walking, lead to an improvement in the stride length and gait speed in the PD patients without evidence of different modulation on spinal and corticospinal parameters.
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Teste de Esforço/métodos , Exercício Físico/fisiologia , Doença de Parkinson/fisiopatologia , Doença de Parkinson/reabilitação , Caminhada/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Fenômenos Biomecânicos/fisiologia , Terapia por Exercício/métodos , Feminino , Marcha/fisiologia , Reflexo H/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/fisiologia , Doença de Parkinson/diagnóstico , Projetos Piloto , Velocidade de Caminhada/fisiologiaRESUMO
The purpose of the present systematic review and meta-analysis was to explore the effects of transcranial direct current stimulation (tDCS) on endurance (i.e., time to task failure (TTF)) and maximal voluntary contraction (MVC). Furthermore, we aimed to analyze whether the duration of stimulation, the brain region targeted for stimulation, and the task performed could also influence motor performance. We performed a systematic literature review in the databases MEDLINE and Web of Science. The short-term effects of anodal tDCS and sham stimulation (placebo) were considered as experimental and control conditions, respectively. A total of 31 interventions were included (MVC = 13; TTF = 18). Analysis of the strength-related tDCS studies showed small improvements in the MVC (SMD = 0.19; 95% CI = -0.02, 0.41; p = 0.08). However, the results of the endurance-related interventions indicated a moderate effect on TTF performance (SMD = 0.26; 95% CI = 0.07, 0.45; p = 0.008). Furthermore, the sub-analysis showed that anodal tDCS over M1 and stimulation durations longer than 10 min produced the best results in terms of TTF performance enhancement. Additionally, the effects of anodal tDCS were larger during full body exercises (i.e., cycling) when compared to uniarticular tasks. In conclusion, the current meta-analysis indicated that anodal tDCS leads to small and moderate effects on MVC and TTF, respectively.
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Treadmills are often used as rehabilitation devices to improve gait in Parkinson's disease (PD). Kinematic differences between treadmill and overground gait have been reported. However, electromyographic (EMG) patterns during treadmill and overground walking have not been systematically compared. The aim of this study was to assess the effects of treadmill gait on the magnitude of the EMG activity of the lower limb muscles in PD. We measured EMG activity of the tibialis anterior, gastrocnemius medialis, vastus lateralis, and biceps femoris of nine individuals with PD and nine healthy matched controls. Comparisons between walking overground with walking on a treadmill and with walking with a treadmill simulator were carried out. The treadmill simulator is a device that simulates treadmill conditions with the exception of the belt. Our results have shown that treadmill walking is associated with several EMG differences compared with overground walking. The key finding of the study is that coactivation of the thigh muscles was significantly decreased (37%; p = 0.008) in PD subjects when walking on the treadmill in comparison with overground walking. The changes observed in the coactivation level may be related to the belt movement, since no changes were reported during walking with the treadmill simulator. Understanding the differences between treadmill and overground gait as well as the mechanisms that result in improvement of gait disturbances may optimize rehabilitative protocols for patients with PD.