Mirror Visual Feedback to Improve Bradykinesia in Parkinson's Disease

The Role of Mirror Therapy in the Rehabilitation of the Upper Limb's Motor Deficits After Stroke: Narrative Review

Stroke is one of the leading causes of death and disability worldwide and poses a tremendous socioeconomic burden upon individuals, countries and healthcare systems. It causes debilitating symptoms and thus interferes with many aspects of the patient's life, including physical functioning, cognition, emotional status, activities of daily living, social reintegration and quality of life. Post-stroke patients frequently experience functional motor disabilities of the upper limb, which restrict autonomy and self-efficacy and cause limitations in engagement with activities and social participation, as well as difficulties in performing important occupations. It is therefore not surprising that motor impairment or loss of motor function of the upper limb is one of the most devastating sequelae of stroke. On these grounds, achieving optimal functioning of the upper limb after stroke remains a fundamental goal of stroke rehabilitation. Mirror therapy (MT) represents one of the several rehabilitation techniques used for restoring the upper limb's motor function after a stroke. However, conflicting results about the role of MT in the rehabilitation of the upper limb's motor deficits have been reported in the literature. Accordingly, the aim of this narrative review is to summarize existing evidence regarding the effects of MT on the upper limb's motor function in post-stroke patients and to further explore its role when applied in different phases of stroke.

Effect of Mirror Therapy on Upper Limb Function in Children and Adolescents with Hemiplegic Cerebral Palsy: A Systematic Review and Meta-Analysis

BACKGROUND

This review aimed to explore the effect of mirror therapy (MT) on upper limb function in children and adolescents with hemiplegic cerebral palsy (HCP).

METHODS

MEDLINE, CENTRAL, Scopus, PEDro, and Web of Science were systematically searched. PEDro scale  was used for the quality assessment of included trials. Risk of Bias assessment was done using Cochrane Risk-of-bias tool version 2. Meta-analysis was performed on four of the seven studies included.

RESULTS & CONCLUSION

The majority of the trials included in this review found MT efficacious in improving motor function in HCP. Quantitative analysis of the included trials using QUEST scores for evaluation of quality of upper extremity function revealed positive but non-significant difference between the groups (MD = -0.12; 95% CI = -2.57,2.33; Z = 0.09, p = .92). Pooled analysis of the included trials using BBT, however, favored control (MD = 4.98; 95% CI = 2.32,7.63; Z = 3.67, p = .0002).

Facial emotion expressivity in patients with Parkinson's and Alzheimer's disease

Parkinson's disease (PD) and Alzheimer's disease (AD) are neurodegenerative disorders with some overlapping clinical features. Hypomimia (reduced facial expressivity) is a prominent sign of PD and it is also present in AD. However, no study has experimentally assessed hypomimia in AD and compared facial expressivity between PD and AD patients. We compared facial emotion expressivity in patients with PD, AD, and healthy controls (HCs). Twenty-four PD patients, 24 AD patients and 24 HCs were videotaped during neutral facial expressions and while posing six facial emotions (anger, surprise, disgust, fear, happiness, and sadness). Fifteen raters were asked to evaluate the videos using MDS-UPDRS-III (item 3.2) and to identify the corresponding emotion from a seven-forced-choice response format. We measured the percentage of accuracy, the reaction time (RT), and the confidence level (CL) in the perceived accuracy of the raters' responses. We found the highest MDS-UPDRS 3.2 scores in PD, and higher in AD than HCs. When evaluating the posed expression captures, raters identified a lower percentage of correct answers in the PD and AD groups than HCs. There was no difference in raters' response accuracy between the PD and AD. No difference was observed in RT and CL data between groups. Hypomimia in patients correlated positively with the global MDS-UPDRS-III and negatively with Mini Mental State Examination scores. PD and AD patients have a similar pattern of reduced facial emotion expressivity compared to controls. These findings hold potential pathophysiological and clinical implications.

Virtual reality as an intervention tool for upper limbs in Parkinson’s disease: a case series

ABSTRACT Parkinson’s disease (PD) is a neurodegenerative disorder in which dopaminergic loss occurs in the basal nuclei region. One major complaint associated with PD is upper extremity motor deficits (UE), frequently reported in difficulties to perform activities of daily living (ADL), which may negatively affect quality of life. In recent years new technologies have emerged to assist the UE rehabilitation process in PD, such as virtual reality. Therefore, this study sought to verify the effects of an intervention in the UE with semi-immersive virtual reality equipment on ADLs and quality of life of individuals with PD. Six individuals with PD were selected for intervention, and evaluated by the Mini Mental State Examination, the Hoehn & Yahr Scale, the Unified Parkinson’s Disease Rating Scale (UPDRS), the Parkinson’s Disease Questionnaire (PDQ-39) and the test d’évaluation des membres supérieurs de personnes âgées (TEMPA). The interventions lasted 27 minutes per session, twice per week, for 5 weeks, using the Leap Motion Controller. Individuals showed improvement in muscle strength, muscle endurance, ADLs, and quality of life, all statistically significant. In conclusion, the protocol based on virtual reality applied to the upper limbs effectively improved the activities of daily living and quality of life in individuals with PD.

Realidade virtual como ferramenta de intervenção para os membros superiores na doença de Parkinson: série de casos

RESUMO A doença de Parkinson (DP) é uma desordem neurodegenerativa na qual ocorre a perda dopaminérgica na região dos núcleos da base. Uma das principais queixas associadas à DP são os déficits motores dos membros superiores (MMSS) frequentemente relatados em dificuldades para realizar as atividades de vida diária (AVDs), podendo interferir negativamente na qualidade de vida. Nos últimos anos novas tecnologias surgiram para auxiliar no processo de reabilitação dos MMSS na DP, sendo a realidade virtual uma delas. Portanto, este estudo teve como objetivo verificar os efeitos de uma intervenção nos MMSS com equipamento de realidade virtual semi-imersiva nas AVDs e na qualidade de vida de indivíduos com DP. Foram selecionados seis indivíduos com DP para intervenção, avaliados por meio do miniexame do estado mental, da escala de Hoehn e Yahr, da escala unificada de avaliação para a DP (UPDRS), do questionário sobre a doença de Parkinson (PDQ-39) e do test d’évaluation des membres supérieurs de personnes âgées (Tempa). Seis sujeitos foram submetidos à intervenção com duração de 27 minutos por sessão, duas vezes na semana, por cinco semanas, utilizando o Leap Motion Controller. Obteve-se melhora na força muscular, na resistência muscular, nas AVDs e na qualidade de vida, todos com significância estatística. Dessa forma, verificou-se que o protocolo baseado em realidade virtual aplicada nos MMSS foi eficaz para melhorar as AVDs e a qualidade de vida dos indivíduos com DP deste estudo.

Impaired Motor Skill Acquisition Using Mirror Visual Feedback Improved by Transcranial Direct Current Stimulation (tDCS) in Patients With Parkinson's Disease

Recent non-invasive brain stimulation techniques in combination with motor training can enhance neuroplasticity and learning. It is reasonable to assume that such neuroplasticity-based interventions constitute a useful rehabilitative tool for patients with Parkinson's Disease (PD). Regarding motor skill training, many kinds of tasks that do not involve real motor movements have been applied to PD patients. The purpose of this study is to elucidate whether motor skill training using mirror visual feedback (MVF) is useful to patients with PD in order to improve untrained hand performance dependent on the time course of training; and whether MVF combined with anodal transcranial direct current stimulation (tDCS) over primary motor cortex (M1) causes an additional effect based on increased motor cortical excitability. Eighteen right-handed patients with PD in the off-medication state and 10 age-matched healthy subjects (HS) performed four sessions of right-hand ball rotation using MVF (intervention) on two separate days, 1 week apart (day 1 and day 2). HS subjects received only sham stimulation. The intervention included four sessions of motor-skill training using MVF for 20 min comprised of four sets of training for 30 s each. PD patients were randomly divided into two intervention groups without or with anodal tDCS over the right M1 contralateral to the untrained hand. As the behavior evaluation, the number of ball rotations of the left hand was counted before (pre) and immediately after (post) intervention on both days (pre day 1, post day 1, pre day 2, and post day 2). Motor evoked potential (MEP), input-output function, and cortical silent period were recorded to evaluate the motor cortical excitatory and inhibitory system in M1 pre day 1 and post day 2. The number of ball rotations of the left hand and the facilitation of MEP by intervention were significantly impaired in patients with PD compared to HS. In contrast, if anodal tDCS was applied to right M1 of patients with PD, the number of ball rotations in accordance with I-O function at 150% intensity was significantly increased after day 1 and retained until day 2. This finding may help provide a new strategy for neurorehabilitation improving task-specific motor memory without real motor movements in PD.

Actual and Illusory Perception in Parkinson's Disease and Dystonia: A Narrative Review

Sensory information is continuously processed so as to allow behavior to be adjusted according to environmental changes. Before sensory information reaches the cortex, a number of subcortical neural structures select the relevant information to send to be consciously processed. In recent decades, several studies have shown that the pathophysiological mechanisms underlying movement disorders such as Parkinson's disease (PD) and dystonia involve sensory processing abnormalities related to proprioceptive and tactile information. These abnormalities emerge from psychophysical testing, mainly temporal discrimination, as well as from experimental paradigms based on bodily illusions. Although the link between proprioception and movement may be unequivocal, how temporal tactile information abnormalities and bodily illusions relate to motor disturbances in PD and dystonia is still a matter of debate. This review considers the role of altered sensory processing in the pathophysiology of movement disorders, focusing on how sensory alteration patterns differ between PD and dystonia. We also discuss the evidence available and the potential for developing new therapeutic strategies based on the manipulation of multi-sensory information and bodily illusions in patients with these movement disorders.

When Non-Dominant Is Better than Dominant: Kinesiotape Modulates Asymmetries in Timed Performance during a Synchronization-Continuation Task

There is a growing consensus regarding the specialization of the non-dominant limb (NDL)/hemisphere system to employ proprioceptive feedback when executing motor actions. In a wide variety of rhythmic tasks the dominant limb (DL) has advantages in speed and timing consistency over the NDL. Recently, we demonstrated that the application of Kinesio^® Tex (KT) tape, an elastic therapeutic device used for treating athletic injuries, improves significantly the timing consistency of isochronous wrist’s flexion-extensions (IWFEs) of the DL. We argued that the augmented precision of IWFEs is determined by a more efficient motor control during movements due to the extra-proprioceptive effect provided by KT. In this study, we tested the effect of KT on timing precision of IWFEs performed with the DL and the NDL, and we evaluated the efficacy of KT to counteract possible timing precision difference between limbs. Young healthy subjects performed with and without KT (NKT) a synchronization-continuation task in which they first entrained IWFEs to paced auditory stimuli (synchronization phase), and subsequently continued to produce motor responses with the same temporal interval in the absence of the auditory stimulus (continuation phase). Two inter-onset intervals (IOIs) of 550-ms and 800-ms, one within and the other beyond the boundaries of the spontaneous motor tempo, were tested. Kinematics was recorded and temporal parameters were extracted and analyzed. Our results show that limb advantages in performing proficiently rhythmic movements are not side-locked but depend also on speed of movement. The application of KT significantly reduces the timing variability of IWFEs performed at 550-ms IOI. KT not only cancels the disadvantages of the NDL but also makes it even more precise than the DL without KT. The superior sensitivity of the NDL to use the extra-sensory information provided by KT is attributed to a greater competence of the NDL/hemisphere system to rely on sensory input. The findings in this study add a new piece of information to the context of motor timing literature. The performance asymmetries here demonstrated as preferred temporal environments could reflect limb differences in the choice of sensorimotor control strategies for the production of human movement.

Time Processing and Motor Control in Movement Disorders

The subjective representation of “time” is critical for cognitive tasks but also for several motor activities. The neural network supporting motor timing comprises: lateral cerebellum, basal ganglia, sensorimotor and prefrontal cortical areas. Basal ganglia and associated cortical areas act as a hypothetical “internal clock” that beats the rhythm when the movement is internally generated. When timing information is processed to make predictions on the outcome of a subjective or externally perceived motor act, cerebellar processing and outflow pathways appear to be primarily involved. Clinical and experimental evidence on time processing and motor control points to a dysfunction of the neural networks involving basal ganglia and cerebellum in movement disorders. In some cases, temporal processing deficits could directly contribute to core motor features of the movement disorder, as in the case of bradykinesia in Parkinson's disease. For other movement disorders, the relationship between abnormal time processing and motor performance is less obvious and requires further investigation, as in the reduced accuracy in predicting the temporal outcome of a motor act in dystonia. We aim to review the literature on time processing and motor control in Parkinson's disease, dystonia, Huntington's disease, and Tourette syndrome, integrating the available findings with current pathophysiological models; we will highlight the areas in which future explorations are warranted, as well as the aspects of time processing in motor control that present translational aspects in future rehabilitation strategies. The subjective representation of “time” is critical for cognitive tasks but also for motor activities. Recently, greater attention has been devoted to improve our understanding of how temporal information becomes integrated within the mechanisms of motor control. Experimental evidence recognizes time processing in motor control as a complex neural function supported by diffuse cerebral networks including cortical areas, cerebellum, and other subcortical structures (Ivry and Spencer, 2004; Coull and Nobre, 2008). Timing is an essential component of motor control primarily within two types of motor tasks: (i) when producing sequential rhythmic movements or sustained movements of a definite duration (explicit timing); (ii) when the temporal information is used implicitly, such as when coordinating our movements to those of moving objects or individuals within the external environment (implicit timing). In this review, we will provide a brief description of the neural network supporting motor timing focusing only on instrumental information to explain the link between timing and motor control in movement disorders. Then we will review available data on motor timing in Parkinson's disease, dystonia, Huntington's disease, and Tourette syndrome, and discuss how this body of evidence integrates with the available information on the pathophysiology of these movement disorders. Finally, we will discuss the translational aspects of the explored neural mechanisms with respect to future rehabilitation strategies.