Assessment of Force Production in Parkinson's Disease Subtypes.

Muscle weakness is a secondary motor symptom of Parkinson's disease (PD), especially in the subtype characterized by postural instability and gait difficulty (PIGD). Since the PIGD subtype also presents worse bradykinesia, we hypothesized that it also shows a decreased rate of force development, which is linked to an increased risk of falling in PD. Therefore, we investigated the effects of PD and PD subtypes on a force production profile and correlated the force production outcomes with clinical symptoms for each PD subtype. We assessed three groups of participants: 14 healthy older adults (OA), 10 people with PD composing the PIGD group, and 14 people with PD composing the tremor-dominant group. Three knee extension maximum voluntary isometric contractions were performed in a leg extension machine equipped with a load cell to assess the force production. The outcome measures were: peak force and rate of force development (RFD) at 50 ms (RFD50), 100 ms (RFD100), and 200 ms (RFD200). We observed lower peak force, RFD50, RFD100, and RFD200 in people with PD, regardless of subtypes, compared with the OA group (p < 0.05 for all comparisons). Together, our results indicated that PD affects the capacity to produce maximal and rapid force. Therefore, future interventions should consider rehabilitation programs for people with PD based on muscle power and fast-force production, and consequently reduce the likelihood of people with PD falling from balance-related events, such as from an unsuccessful attempt to avoid a tripping hazard or a poor and slower stepping response.

Effect of different types of exercises on psychological and cognitive features in people with Parkinson's disease: A randomized controlled trial.

BACKGROUND: Parkinson's disease (PD) is a neurodegenerative and progressive disease marked by the presence of motor and non-motor symptoms, as psychological and cognitive impairment. Physical exercises have been prescribed as complementary therapy for PD, and the type of intervention and duration of the intervention should be taken into account. OBJECTIVE: We aimed to compare the effect of different exercise modalities (functional mobility, multimodal and cognitive) and length (4 and 8 months) on psychological and cognition in people with PD. This study followed the CONSORT extension for non-pharmacological trials. METHODS: In this randomized controlled trial, we assessed 107 participants between 2011 and 2013. At the end of 3 years, participants with PD (mild to moderate stages) who achieved the criteria were assessed considering 3 different groups of exercise: Multimodal (n=38), Functional Mobility (n=33) and Mental/Leisure (n=36). All 3 interventions were performed for 32 weeks, twice a week, with 60min for each session (64 sessions in total). Psychological and cognitive function were assessed at baseline and after 4 and 8 months. RESULTS: The Functional Mobility and Mental/Leisure training had a potential effect on maintaining cognitive function (executive function, attention and work memory). The Multimodal training did not show a benefit for cognitive features and was not even able to delay the progressive decline in cognitive functions; however, this modality had a positive effect on physical stress after 8 months of exercise. CONCLUSIONS: An intervention that requires high complexity and specific activities, such as locomotor and cognitive exercise, provides a maintenance effect against the degeneration in cognition associated with the progression of PD and thus can delay the progressive decline in cognitive function in PD.

Biomechanical analysis of sit-to-walk in different Parkinson's disease subtypes.

BACKGROUND: The Parkinson's disease Postural Instability and Gait Difficulty subtype is well-known to exhibit higher levels of gait and postural instability and higher frequency of falls. However, no studies have investigated the impact of Parkinson's disease subtypes when performing a highly-challenging postural task, such as sit-to-walk. This task is often used daily and can highlight balance impairments. Thus, the aim of this study was to compare Tremor Dominant and Postural Instability and Gait Difficulty subtypes during sit-to-walk measured by performance, kinematic and kinetic analyses. METHODS: Twenty-four people with Parkinson's disease participated in this study, and were divided into two groups: Tremor Dominant (n = 14) and Postural Instability and Gait Difficulty subtype (n = 10). They performed the sit-to-walk under a time constraint (to pick up a phone placed 4 meters away in order to answer an urgent call). Sit-to-walk overall performance, kinetic and kinematic data were assessed as outcome measures. FINDINGS: The Postural Instability and Gait Difficulty group demonstrated a slower anteroposterior center-of-mass velocity at seat-off, a longer duration of transitional phase and poorer movement fluidity. Furthermore, the Postural Instability and Gait Difficulty group showed a longer sit-to-walk total time. These results indicate that the Postural Instability and Gait Difficulty group performed the task slowly and split the task into two subtasks (sit-to-stand and walking), rather than performing a single, continuous task. INTERPRETATION: The Postural Instability and Gait Difficulty group is unable to perform the sit-to-walk continuously, which might reflect the clinical impairments observed in this Parkinson's disease subtype.

Motor adjustments during time-constrained sit-to-walk in people with Parkinson's disease.

INTRODUCTION: Sit-to-walk (STW) is a sequential task and a merge of sit-to-stand (STS) and gait initiation that are impaired in people with Parkinson's disease (PD). Performing sequential task under time constraint (e.g., stand up and walk to answer an urgent call) might influence people with PD due to their deficits on internal regulation of continuous, rhythmic and fast movements. It is known the PD behavior during STS and gait initiation tasks are impaired, however, little is known regarding PD behavior on STW. Thus, the aim of this study was to assess the motor behavior of people with PD and healthy older adults during the STW task under time constraint. METHODS: Fourteen people with idiopathic PD and 14 healthy older adults (OA) participated in this study. They performed the STW task under a time constraint. STW performance (STW total duration, duration of each of the 4 phases of the STW, and the drop in the center of mass (COM) momentum, identified as Fluidity Index - FI), kinematics and kinetics outcomes were assessed throughout the task. RESULTS: The PD group showed increased STW total time and lower FI, longer seat-off (Phase 1) time and first step (Phase 4) when compared to the OA group. Furthermore, the PD group showed more motor impairments (kinematics and kinetics) than the OA group throughout the task from seat-off until heel-off. Also, people with PD exhibited larger mediolateral COM displacement in the standing phase (Phase 2) and greater ground reaction force (GRF) in Phases 1 and 3. CONCLUSIONS: We observed that people with PD exhibited more restrictions when compared with healthy older adults on their STW performance, COM and GRF parameters during the STW under time constraint. Some clinical impairments usually observed in people with PD might explain their STW performance such as, motor planning deficits, less automatic motor control and mediolateral balance impairments.

Predictors of the functional reach test in people with parkinson's disease / Preditores do desempenho no teste de alcance funcional em pessoas com doença de parkinson

ABSTRACT Postural instability, a fundamental signal/symptom of Parkinson's disease (PD), is characterized by the association between postural alignment, joint range of motion, and muscular rigidity. The aim of the present study was to analyze the relationship between performance in the functional reach test (FRT) and associated factors such as joint range of motion and PD clinical features. Twenty-five people with PD in stages 1 and 1.5 of the Hoehn & Yahr scale participated in the study. The analyzed dependent variables were: FRT performance and scores in the items of clinical evaluation of the Unified Parkinson's Disease Rating Scale: pull-test, motor rigidity, and motor condition were used. The average distance in the FRT was 25.3 cm and the mean anterior-posterior displacement of the center of pressure was 2.69 cm. The ankle range of motion was associated with FRT performance, while postural stability was associated with the anterior-posterior displacement of the center of pressure during the FRT. We conclude that FRT performance in people with PD is determined by the individual level of balance and by the ankle joint amplitude and muscular rigidity and functional alterations due to aging are responsible for FRT performance.

RESUMO A instabilidade postural, um sinal/sintoma cardinal da doença de Parkinson (DP), é caracterizada pela associação entre alinhamento postural, amplitude de movimento e rigidez muscular. O objetivo foi analisar a relação entre o desempenho no teste de alcance funcional (TAF) e fatores relacionados a amplitude de movimento e aspectos clínicos da doença. Participaram 25 pessoas com DP nos estágios 1,0 e 1,5 da Hoehn e Yahr. As variáveis dependentes analisadas foram: desempenho no TAF e as pontuações nos itens da avaliação clínica da UnifiedParkinson'sDisease Rating Scale: teste de retropulsão, rigidez muscular e condição motora. A distância média no TAF foi de 25,3 cm e o deslocamento anteroposterior médio do centro de pressão foi de 2,69 cm. A amplitude de movimento articular do tornozelo está associada ao desempenho no TAF, enquanto a estabilidade postural está associada ao deslocamento anteroposterior do centro de pressão durante o TAF. Conclui-se que o desempenho no TAF em pessoas com DP é determinado pelo nível individual de equilíbrio e pela amplitude articular do tornozelo e a rigidez muscular e alterações funcionais do envelhecimento são responsáveis pelo desempenho no TAF.

PARKINSON'S DISEASE PATIENTS WITH DOMINANT HEMIBODY AFFECTED BY THE DISEASE RELY MORE ON VISION TO MAINTAIN UPRIGHT POSTURAL CONTROL.

This study assesses the association between disease onset side (dominant or non-dominant) and vision on postural control of Parkinson's disease patients. Patient volunteers composed two groups, according to the onset side affected: Dominant group (n=9; M age=66.1 yr., SD=7.2; 6 women, 3 men) and Non-dominant group (n=9; M age=67.4 yr., SD=6.4; 6 women, 3 men). The groups' postural control was assessed by posturography during quiet upright stance in two conditions, Eyes open and Eyes closed. Two-way analyses of variance (ANOVAs; group×condition) with repeated measures for the second factor assessed the differences associated with affected hemibody and vision on postural control. Analyses indicated that patients with the dominant side affected also presented significantly greater variation in center of pressure than those with the non-dominant side affected, mainly in the Eyes closed condition. The results demonstrate a higher reliance on vision in the dominant side, possibly to compensate somatosensory system impairments. These results also highlight the importance of analyzing the hemibody affected by the disease when postural control is assessed in this population.

Análise cinética e cinemática do levantar e andar em jovens e idosos / Kinetic and kinematic analysis of sit to walk task in young and elderly people / Análisis cinético y cinemático de la acción de levantarse y caminar en jóvenes y personas mayores

ResumoA tarefa de levantar e andar (LEA) é muito usada no dia a dia e há a necessidade de conhecer o comportamento de idosos nesse tipo de ação. Diante disso, o objetivo foi avaliar jovens (GJ) e idosos (GI) na tarefa de LEA. Foram realizadas avaliações cinéticas e cinemáticas e do desempenho da tarefa entre os grupos. Após a análise estatística, foi observada apenas diferença estatística para a variável de máxima força vertical durante a fase perda de contato com o assento ao término do levantar, assim como o tempo de desempenho dessa fase foi menor para o GJ. O envelhecimento causa um impacto significativo na força e contribui, assim, para um maior dispêndio de tempo ao levantar da cadeira. Com isso, maior atenção deve ser dada à fase de transição da LEA.

AbstractThe sit to walk (STW) is a task performed in daily life and is needed to know the older people behavior in this task. Therefore, the aim of this study was to evaluate young (YG) and older people (OG) when performing the STW. Kinetic, kinematic and task performance were assessed by each group. Statistical procedures showed differences only for vertical maximal ground reaction force during the seat off, such as the lower time to perform this phase for YG. The aging lead a significant impact in the strength force in limbs, due to this the elderly spend more time to rising up a chair. Therewith greater attention is necessary in transition phase, mainly by elderly exposure and increased chance of falls.

ResumenLa acción de levantarse y caminar (LYC) es muy frecuente en la vida diaria y es necesario saber cómo la realizan las personas mayores. Por tanto, el objetivo de este estudio ha sido evaluar a personas jóvenes (PJ) y personas mayores (PM) cuando realizan la acción de LYC. Se llevaron a cabo mediciones de tipo cinético, cinemático y del desempeño de esta acción en cada grupo. Los procedimientos estadísticos mostraron diferencias solo en la máxima fuerza vertical de reacción terrestre al levantarse del asiento, así como en el menor tiempo empleado por las PJ para llevar a cabo esta fase. El envejecimiento causa un impacto significativo en la fuerza de las extremidades y por ello las personas mayores necesitan más tiempo para levantarse de una silla. De esta manera, es necesario prestar mayor atención a la fase de transición de la acción de LYC.

Does proprioceptive system stimulation improve sit-to-walk performance in healthy young adults?

[Purpose] Sit-to-walk performance is linked to proper proprioceptive information processing. Therefore, it is believed that an increase of proprioceptive inflow (using muscle vibration) might improve sit-to-walk performance. However, before testing muscle vibration effects on a frail population, assessment of its effects on healthy young people is necessary. Thus, the aim of this study was to investigate the effects of muscle vibration on sit-to-walk performance in healthy young adults. [Subjects and Methods] Fifteen young adults performed the sit-to-walk task under three conditions: without vibration, with vibration applied before movement onset, and with vibration applied during the movement. Vibration was applied bilaterally for 30 s to the tibialis anterior, rectus femoris, and upper trapezius muscles bellies. The vibration parameters were as follows: 120 Hz and 1.2 mm. Kinematics and kinetic data were assessed using a 3D motion capture system and two force plates. The coordinates of reflective markers were used to define the center-of-mass velocities and displacements. In addition, the first step spatiotemporal variables were assessed. [Results] No vibration effect was observed on any dependent variables. [Conclusion] The results show that stimulation of the proprioceptive system with local muscle vibration does not improve sit-to-walk performance in healthy young adults.