Postural Control In People Research Articles

The effectiveness of virtual reality for rehabilitation of Parkinson disease: an overview of systematic reviews with meta-analyses

BackgroundAn increasing number of systematic reviews (SRs) and meta-analyses (MAs) of clinical trials have begun to investigate the effects of virtual reality (VR) in patients with Parkinson disease (PD). The aim of this overview was to systematically summarize the current best evidence for the effectiveness of VR therapy for the rehabilitation of people with PD.MethodsWe searched SR-MAs based on randomized controlled trials (RCTs) for relevant literature in PubMed, Embase, and Cochrane library databases for systematic reviews from inception to December 5, 2020, and updated to January 26, 2022. The methodological quality of included SR-MAs was evaluated with the Assessing the Methodological Quality of Systematic Reviews 2 (AMSTAR-2), and the certainty of evidence for outcomes with the Grading of Recommendations, Assessment, Development and Evaluation (GRADE). We created an evidence map using a bubble plot format to represent the evidence base in 5 dimensions: effect size of VR therapy versus active intervention (AT), clinical outcome area, number of trials, statistical significance, and certainty of evidence.ResultsFrom a total of 585 reports, 12 reviews were identified, of which only one was rated moderate quality, three were rated low quality, and eight were rated critically low quality by AMSTAR 2. Compared with AT, VR therapy induced increased benefits on stride/step length, balance, and neuropsychiatric symptoms. Compared with passive intervention (PT), VR therapy had greater effects on gait speed, stride/step length, balance, activities of daily living, and postural control in people with PD. Certainty of evidence varied from very low to moderate.ConclusionsWe found the methodological quality of the reviews was poor, and certainty of the most evidence within them was low to very low. We were therefore unable to conclude with any confidence that, in people with PD, VR therapy is harmful or beneficial for gait, balance, motor function, quality of life, activities of daily living, cognitive function, neuropsychiatric symptoms, and postural control. In the future, rigorous-designed, high-quality RCTs with larger sample sizes are needed to further verify the effectiveness of VR therapy in the treatment of PD.

The effects of balance and core stability training on postural control in people with visual impairment: A systematic review

Visual impairment is one of the most common functional impairments that considerably affects the postural control process and the ability to maintain balance. The purpose of this study was to perform a systematic review concerning the effects of balance and core stability training on postural control in individuals who are visually impaired. This article comprehensively reviewed studies on balance in individuals who are blind from the following databases: PubMed, Embase, Web of Science, and Scopus from 2007 to 2021. Inclusion and exclusion criteria were people who were blind or visually impaired (acquired and congenital), men and women, all ages, and at least 6 weeks balance or core stability training program. Twelve articles were included in this review. Individuals with visual impairment and blindness from all ages were included in this study. According to this review, all balance and core stability protocols in this article have positive effects on balance and postural control for individuals with visual impairments. Therefore, balance and core stability intervention for at least 6 weeks is one of the more well-established protocols for improving balance and postural control in people with visual impairment and can have a positive impact in risk of falling regardless of age, gender, or severity of visual impairment.

Perturbation-based training enhances anticipatory postural control in individuals with chronic stroke: a pilot study.

Individuals with stroke commonly have impaired balance control. The aim of this study was to investigate the effect of targeted intervention on anticipatory postural adjustments (APAs) and postural control in people with stroke. Six participants with unilateral hemiparesis due to a stroke (5.0-8.4 years post stroke) participated in a two-phase random crossover study. The participants received in counterbalanced order (a) 2 weeks of experimental, targeted intervention (pushing a medicine ball attached to the ceiling using their unaffected upper extremity) and (b) 2 weeks of control, self-guided general mobility exercise program with a 1-week washout period in between. All study participants were assessed with laboratory tests before and after each intervention. Lab tests included predictable external perturbations induced by a pendulum impact and clinical assessments of balance. Bilateral electromyographic activity of eight trunk and leg muscles and center of pressure (COP) displacements were recorded, and data during the anticipatory and compensatory phases of postural control were analyzed. After the experimental intervention, as compared to control intervention, the participants showed earlier APA onsets (P < 0.05), smaller COP displacements (P < 0.05), and improved [although not significantly (P >0.05)] scores of clinical tests of balance. The results of this feasibility study provide a foundation for developing balance rehabilitation protocols focused on improving APAs in individuals with neurological disorders.

Effect of resistance training on balance and postural control in people with Parkinson’s: A systematic review

BackgroundPhysical exercise has contributed significantly to the quality of life of the population. Therefore, countless specialists have established relationships between t people who perform physical exercise and success in the treatment of diseases, such as Parkinson’s disease in older adults. ObjectiveThe aim of this research is to analyse the influence of resistance training in the correlation of balance and postural control in people with Parkinson’s disease. MethodA systematic review was conducted according to the recommendations of the Preferred Reporting Items for Systematic Reviews And Meta-Analyses (PRISMA), in consultation with the PubMed, Scielo, BVS (Lilacs), ScienceDirect and Cochrane databases, based on the influence of resistance training on postural balance and control in older adults with Parkinson’s disease, highlighting as the main assessment tool the Movement Disorders Society — Unified Parkinson’s Disease Rating Scale. ResultsAfter searching the selected databases and considering the inclusion and exclusion criteria of this study, 10 studies were selected to compose this review and a total of 556 participants were pooled. It was observed that most of the interventions (60%) had a duration of approximately 30−45 min over eight to twelve weeks, the most used measuring instruments were the BESTest (Balance Evaluation System Test), FOG-Q (Freezing of Gait Questionnaire) and the MDS-UPDRS (Movement Disorders Society-Unified Parkinson’s Disease Rating Scale). ConclusionPhysical exercise plays a fundamental role in the intervention and prevention of Parkinson’s disease symptoms with regard to balance, strength, and quality of life.

Efecto del entrenamiento resistido sobre el equilibrio y control postural en personas con párkinson: una revisión sistemática

BackgroundPhysical exercise has contributed significantly to the quality of life of the population. Therefore, countless specialists have established relationships between t people who perform physical exercise and success in the treatment of diseases, such as Parkinson's disease in older adults. ObjectiveThe aim of this research is to analyse the influence of resistance training in the correlation of balance and postural control in people with Parkinson's disease. MethodA systematic review was conducted according to the recommendations of the Preferred Reporting Items for Systematic Reviews And Meta-Analyses (PRISMA), in consultation with the PubMed, Scielo, BVS (Lilacs), ScienceDirect and Cochrane databases, based on the influence of resistance training on postural balance and control in older adults with Parkinson's disease, highlighting as the main assessment tool the Movement Disorders Society - Unified Parkinson's Disease Rating Scale. ResultsAfter searching the selected databases and considering the inclusion and exclusion criteria of this study, 10 studies were selected to compose this review and a total of 556 participants were pooled. It was observed that most of the interventions (60%) had a duration of approximately 30-45minutes over 8to 12weeks, the most used measuring instruments were the BESTest (Balance Evaluation System Test), FOG-Q (Freezing of Gait Questionnaire) and the MDS-UPDRS (Movement Disorders Society-Unified Parkinson's Disease Rating Scale). ConclusionPhysical exercise plays a fundamental role in the intervention and prevention of Parkinson's disease symptoms with regard to balance, strength, and quality of life.

Does Acute Exercise Stress Affect Postural Stability and Cognitive Function in Subjects with Chronic Ankle Instability?

Altered postural control in people with chronic ankle instability (CAI) may be attributed to deficits that are associated with neurocognitive function. Acute training is another factor that may negatively affect postural control and increase the risk of ankle sprain. The purpose of this investigation was to determine the effect of acute exercise on postural stability and cognitive function among patients with CAI. Fifteen patients with CAI (aged 21.5 ± 2.0 years) and 15 healthy controls (aged 20.3 ± 1.7 years) completed a single-limb stance postural control test and a battery of computer-based cognitive tests before and after acute exercise. The overall stability index (OSI) was used as a measure of postural stability. The cognitive domains tested were global cognitive score, executive function, attention, visual-spatial perception, information processing, and fine motor control. Subjects in both groups had similar OSI scores, with a trend for reduced stability in the CAI after the exercise protocol (p = 0.053). There were no differences between the groups in all cognitive domains before or after exercise. Following exercise, the domains of overall cognitive score, visual-spatial perception, and information processing speed improved in both groups (p = 0.003, p = 0.033, p = 0.001; respectively). These findings should be considered with caution due to the heterogeneity of the CAI population.

Star-Shape Kinesio Taping Is Not Better Than a Minimal Intervention or Sham Kinesio Taping for Pain Intensity and Postural Control in Chronic Low Back Pain: A Randomized Controlled Trial

ObjectiveThis study investigated the effects of star-shape Kinesio taping (KT) compared with both sham KT and minimal intervention (MI) on pain intensity and postural control. DesignRandomized controlled trial. SettingOutpatient physical therapy. ParticipantsA total of 120 people with chronic low back pain (CLBP) aged 18-60 years (N=120). InterventionsStar-shape KT, sham KT (no tension), and MI (educational booklet for self-management counseling). Main Outcome MeasuresThe primary outcome measures were pain intensity and center of pressure (COP) mean sway speed, and disability score (Oswestry Disability Index) was a secondary outcome. The outcomes were obtained immediately after initial KT application, on the seventh day of intervention and at the 1-month follow-up. Linear mixed-model analyses using Bonferroni post hoc analyses were applied to investigate between-group differences. The model included treatment, time, and treatment×time interaction as fixed effects. ResultsPain intensity was significantly lower for the star-shape KT group than for the MI group (mean difference [MD], −1.35; 95% confidence interval [CI], −2.63 to −0.07) immediately after the intervention and on the seventh day of intervention (MD, −1.32; 95% CI, −2.56 to −0.07). No difference in pain intensity between star-shape KT vs sham-KT groups was observed. In addition, no significant between-group differences were observed for the COP mean sway speed and disability score at any of the follow-up times. ConclusionsOur results showed no meaningful effect of star-shape KT intervention on pain intensity and postural control in people with CLBP compared with MI or sham KT. The observed reduction of 1.3 units between star-shape KT and MI groups was statistically different, but it could not be considered clinically relevant. The results of this trial suggest that benefits from KT are more likely attributable to contextual factors rather than specific taping parameters.

Center of pressure responses to unpredictable external perturbations indicate low accuracy in predicting fall risk in people with Parkinson's disease.

Falls are associated with impairment in postural control in people with Parkinson's disease (PwPD). We aimed to predict the fall risk through models combining postural responses with clinical and cognitive measures. Also, we compared the center of pressure (CoP) between PwPD fallers and non-fallers after unpredictable external perturbations. We expected that CoP parameters combined with clinical and cognitive measures would predict fall risk. Seventy-five individuals participated in the study. CoP parameters were measured during postural responses through five trials with unpredictable translations of the support-surface in posterior direction. Range and peak of CoP were analyzed in two periods: early and late responses. Time to peak (negative peak) and recovery time were analyzed regardless of the periods. Models included the CoP parameters in early (model 1), late responses (model 2), and temporal parameters (model 3). Clinical and cognitive measures were entered into all models. Twenty-nine participants fell at least once, and 46 PwPD did not fall during 12months following the postural assessment. Range of CoP in late responses was associated with fall risk (p=.046). However, although statistically non-significant, this parameter indicated low accuracy in predicting fall risk (area under the curve=0.58). Fallers presented a higher range of CoP in early responses than non-fallers (p=.033). In conclusion, although an association was observed between fall risk and range of CoP in late responses, this parameter indicated low accuracy in predicting fall risk in PwPD. Also, fallers demonstrate worse postural control during early responses after external perturbations than non-fallers, measured by CoP parameters.

The effect of proprioceptive training on postural control in people with diabetes: A randomized clinical trial comparing delivery at home, under supervision, or no training

Objective: Analyze postural control in the bipedal position as well as during gait and functional tests in patients with type 2 diabetes mellitus after supervised and unsupervised proprioceptive training. Design: A three-group randomized controlled trial. Setting: Physiotherapeutic Resources Lab, Department of Health Sciences, Ribeirão Preto Medical School, University of São Paulo Subjects: Eighty patients with type 2 diabetes allocated to three groups: control, home training, and supervised training. Interventions: The supervised and home training groups performed two weekly sessions of proprioceptive exercises for 12 weeks. The control group was not submitted to any of treatment. Main measures: Bipedal balance, gait, and performance on functional tests were evaluated before and after 12 weeks using the Balance Evaluation Systems Test (BESTest) and the force plate. Results: No significant improvements were found regarding postural control, gait, or performance on the functional tests, as evidenced by the inter-group comparisons of the total BESTest score [control: 90.7 (81.5–92.6); home training: 85.2 (77.8–90.3); supervised training: 88.4 (82.6–91.4), P > 0.05] as well as the tests performed on the force plate (P > 0.05). The clinical effect size of the proposed intervention was less than 0.2, demonstrating no effect for the main outcome variable evaluated by the “Sensory Orientation” item of the BESTest and by the mCTSIB (pressure plate). Conclusions: The proposed proprioceptive training did not lead to improvements in postural control in patients with type 2 diabetes with no clinical signs of diabetic distal polyneuropathy when analyzed using the BESTest clinical evaluation and a force plate. Trial registration: NCT01861392 (clinicaltrials.gov).

Prolonged Standing Task Affects Adaptability of Postural Control in People With Parkinson’s Disease

Background Studies on short-term upright quiet standing tasks have presented contradictory findings about postural control in people with Parkinson’s disease (pwPD). Prolonged trial durations might better depict body sway and discriminate pwPD and controls. Objective The aim of this study was to investigate postural control in pwPD during a prolonged standing task. Methods A total of 26 pwPD and 25 neurologically healthy individuals performed 3 quiet standing trials (60 s) before completing a constrained prolonged standing task for 15 minutes. Motion capture was used to record body sway (Vicon, 100 Hz). To investigate the body sway behavior during the 15 minutes of standing, the analysis was divided into three 5-minute-long phases: early, middle, and late. The following body sway parameters were calculated for the anterior-posterior (AP) and medial-lateral (ML) directions: velocity, root-mean-square, and detrended fluctuations analysis (DFA). The body sway area was also calculated. Two-way ANOVAs (group and phases) and 1-way ANOVA (group) were used to compare these parameters for the prolonged standing and quiet standing, respectively. Results pwPD presented smaller sway area (P < .001), less complexity (DFA; AP: P < .009; ML: P < .01), and faster velocity (AP: P < .002; ML: P < .001) of body sway compared with the control group during the prolonged standing task. Although the groups swayed similarly (no difference for sway area) during quiet standing, they presented differences in sway area during the prolonged standing task (P < .001). Conclusions Prolonged standing task reduced adaptability of the postural control system in pwPD. In addition, the prolonged standing task may better analyze the adaptability of the postural control system in pwPD.

Effects of contemporary dance and physiotherapy intervention on balance and postural control in Parkinson’s disease

Purpose To describe the effects of a contemporary dance program, combined with conventional physiotherapy, on postural control, satisfaction and adherence in mild-moderate Parkinson’s disease (PD) patients. Methods A withdrawal/reversion test with three intervention periods. Each period lasts for two months: physiotherapy, physiotherapy + dance and withdrawing dance and continuing with the physiotherapy sessions. Berg Balance Scale (BBS), Timed Up & Go test (TUG), Sensory Organization Test (SOT), Motor Control Test (MCT) and Rhythmic Weigh Shift (RWS) were assessed at T1 (baseline), T2 (post-physiotherapy treatment), T3 (post-physiotherapy and dance) and T4 (post-physiotherapy). A satisfaction questionnaire and adherence were registered. Results 27 patients (67.32 ± 6.14 yrs) completed the study. Statistical analysis revealed differences between T2-T3 (p = 0.027), T2-T4 (p = 0.029), T1-T3 (p = 0.010) and T1-T4 (p = 0.008) for BBS; and between T1-T2 (p = 0.037), T1-T3 (p = 0.005), T1-T4 (p = 0.004), T2-T3 (p = 0.022) and T2-T4 (p = 0.041) for TUG. Significant differences for CES (p < 0.001), VEST (p = 0.024) and strategy (p = 0.011) were observed, but not for MCT. Lateromedial velocity (p = 0.003) and anteroposterior velocity (p < 0.001) were significant for RWT. Patients showed a high level of satisfaction and adherence. Conclusions A short 8-weeks contemporary dance program plus combined physiotherapy shows benefits in functional mobility and balance, with a high degree of satisfaction and adherence in PD. IMPLICATIONS FOR REHABILITATION Contemporary dance, combined with physiotherapy, is a useful therapeutic tool to treat balance disorders and postural control in people with PD. A short 8-weeks contemporary dance program plus combined physiotherapy shows high satisfaction in people with PD. Contemporary dance, combined with physiotherapy, shows high adherence in people with mild-moderate PD to treat postural control.

Use of time-to-boundary to assess postural instability and predict functional mobility in people with diabetes mellitus and peripheral neuropathy

BackgroundPeople with diabetes mellitus and peripheral neuropathy (DMPN) often have balance and mobility deficits. Time-to-boundary (TTB) is a parameter of postural control that combines position and velocity center of pressure data. While not previously investigated, assessment of TTB may provide new insight regarding postural control in people with DMPN. Research questionIs TTB reduced and related to a measure of mobility in people with DMPN? MethodsThirteen people with DMPN without fall history and 13 healthy matched controls participated in this case-control study. Participants stood in double-limb stance on a force plate. The anterior-posterior and medial-lateral center of pressure position and velocity relative to the boundaries of the base of support were used to calculate TTB (s). Lower values indicate less postural control. Time-to-failure during single-limb stance was a secondary measure of postural control. Time to complete the Timed Up and Go (TUG) was our measure of mobility. Longer TUG times correspond to decreased mobility, strength, and balance. Independent t-tests or Mann-Whitney U tests were conducted to assess group differences. Bivariate correlations between task outcomes were conducted. ResultsAnterior-posterior TTB and single-limb stance times were shorter in people with DMPN (p ≤ 0.04). TUG times were longer in the DMPN group (p = 0.04). In the DMPN group, inverse relationships were observed between TTB and TUG (anterior-posterior R2 = .34; medial-lateral R2 = .49; both p = 0.01), but not between single-limb stance times and TTB or TUG. SignificanceTTB was a sensitive measure of postural control in people with DMPN. The detected relationship between TTB and TUG newly establishes TTB as a clinically meaningful indicator of balance and function. Study findings may serve to further guide balance screening and rehabilitation efforts in people with DMPN.

Commentary to the Newly Rising Aquatic Exercise: Ai Chi

As aquatic therapy has become an important rehabilitative option, more exercise programs have emerged. Ai Chi, is one of the therapeutic aquatic exercise concepts with growing potential. In our previous study, both types of aquatic exercise, Ai Chi and conventional exercise, supported the restoration of postural control in people with chronic stroke, whereas Ai Chi seemed to have larger effects.

Head stabilization during standing in people with persisting symptoms after mild traumatic brain injury

Increased postural sway is often observed in people with mild traumatic brain injury (mTBI), but our understanding of how individuals with mTBI control their head during stance is limited. The purpose of this study was to determine if people with mTBI exhibit increased sway at the head compared with healthy controls. People with persisting symptoms after mTBI (n = 59, 41 women) and control participants (n = 63, 38 women) stood quietly for one minute in four conditions: eyes open on a firm surface (EO-firm), eyes closed on a firm surface (EC-firm), eyes open on a foam pad (EO-foam), and eyes closed on foam (EC-foam). Inertial sensors at the head, sternum, and lumbar region collected tri-axial accelerations. Root-mean-square (RMS) accelerations in anteroposterior (AP) and mediolateral (ML) directions and sway ratios between the head and sternum, head and lumbar, and sternum and lumbar region were compared between groups. Temporal coupling of anti-phase motion between the upper and lower body angular accelerations was assessed with magnitude squared coherence and cross-spectral phase angles. People with mTBI demonstrated greater sway than controls across conditions and directions. During foam-surface conditions, the control group, but not the mTBI group, reduced ML sway at their head and trunk relative to their lumbar by increasing the expression of an anti-phase hip strategy within the frontal plane. These results are consistent with suggestions of inflexible or inappropriate postural control in people with mTBI.

Effect of Dance on Postural Control in People with Parkinson’s Disease: A Meta-Analysis Review

This systematic review verified the effect of dance on postural control in people with Parkinson's disease (PD) and investigated whether this practice can be as effective over a short period as when it is performed over a longer period in relation to the postural control of this population. The search was performed in April 2019 in nine databases. Only randomized/quasi-randomized controlled trials with participants with idiopathic PD were included. The meta-analysis of the 11 articles included, with 13 results, showed that the 211 participants with PD, who belonged to the group performing dance, had a standardized mean difference of postural control 0.82 [0.52, 1.12] greater than the 182 participants who were in a control situation. The statistically significant results of this meta-analysis indicate that dance can improve postural control in people with PD in a short period of time and therefore contribute to the prevention of falls.

Psychometric properties and domains of postural control tests for individuals with knee osteoarthritis: a systematic review

Purpose: Individuals with knee osteoarthritis (OA) commonly demonstrate impaired postural control. Comprehensive assessment of postural control is required to identify impairments, inform appropriate management and evaluate treatment effectiveness. Our aim was to systematically review psychometric properties of tests that assess postural control in people with knee OA and secondly, to determine domains of postural control measured by these tests.

Psychometric properties and domains of postural control tests for individuals with knee osteoarthritis: a systematic review.

Individuals with knee osteoarthritis (OA) commonly demonstrate impaired postural control. We aimed to systematically review psychometric properties of tests that assess postural control in people with knee OA and secondly, to determine domains of postural control measured by these tests. PubMed, CINAHL, Embase and Web of Science databases were searched to January 2019. Two independent review authors screened references according to eligibility criteria. The Consensus-based Standards for the selection of health Measurement Instruments were used to evaluate study methodological quality. Postural control tests identified from included studies were assessed to determine postural control constructs using the Systems Framework for Postural Control identifying nine domains. Following the screening of 2643 references, five cross-sectional studies and one longitudinal study (n = 408) were included. Four studies evaluated reliability, validity or responsiveness of three clinical measures: Community Balance and Mobility Scale, Star Excursion Balance Test and Tinetti Performance Oriented Mobility Assessment. Two assessed reliability or validity of a force platform. Results showed that evidence for reliability, validity and responsiveness of all these postural measures is limited. The most common domain of postural control assessed was 'static stability'. No study used measures that evaluated all nine postural control domains. Our results highlight limited investigation of psychometric properties specific to postural control in knee OA. The few existing ones have limitations regarding psychometric robustness and completeness regarding different domains of postural control. Future research should focus on verifying the quality of existing tools to evaluate postural control in knee OA for research and clinical purposes.

The Acute Effects of Axial Loading on Postural Control in People with Multiple Sclerosis

The Acute Effects of Axial Loading on Postural Control in People with Multiple Sclerosis

Structural Neural Correlates of Impaired Postural Control in People with Secondary Progressive Multiple Sclerosis.

Secondary progressive multiple sclerosis (SPMS) is characterized by worsening of postural control and brain atrophy. However, little is known about postural deficits and their neuroanatomical correlates in this population. We aimed to determine the neuroanatomical correlates of postural deficits in people with SPMS and whether posture control deteriorates concomitantly with the brain and spinal cord atrophy in 2 years in SPMS. This study is a post hoc analysis of data from 27 people with SPMS (mean ± SE age, 58.6 ± 1.1 years). Participants had magnetic resonance imaging (MRI) of the brain and cervical spinal cord followed by sway testing using inertial sensors during standing with eyes open (EO) and eyes closed without (EC) and with (ECC) a cognitive task. Partial correlations investigated relationships between postural control and MRI measures at baseline and 2 years. At baseline, sway measures were inversely related to cortical thickness and cord cross-sectional area (CSA) during the EO task but only to cord CSA with EC (P < .05). After 2 years, the percentage change in sway amplitude and dispersion during EO tasks significantly related to the percentage decline in cord CSA (P < .01). Cortical and spinal cord inputs are essential for regulation of postural control during standing with EO in SPMS. Without visual input, people with SPMS preferentially rely on somatosensory inputs from the spinal cord for maintaining postural control. Postural deficits related to cord atrophy over 2 years, suggesting that postural control may be a surrogate marker of disease progression in people with SPMS.

Mobility assessment in people with Alzheimer disease using smartphone sensors

BackgroundUnderstanding the functional status of people with Alzheimer Disease (AD), both in a single (ST) and cognitive dual task (DT) activities is essential for identifying signs of early-stage neurodegeneration. This study aims to compare the performance quality of several tasks using sensors embedded in an Android device, among people at different stages of Alzheimer and people without dementia. The secondary aim is to analyze the effect of cognitive task performance on mobility tasks.MethodsThis is a cross-sectional study including 22 participants in the control group (CG), 18 in the group with mild AD and 22 in the group with moderate AD. They performed two mobility tests, under ST and DT conditions, which were registered using an Android device. Postural control was measured by medial-lateral and anterior-posterior displacements of the COM (MLDisp and APDisp, respectively) and gait, with the vertical and medial-lateral range of the COM (Vrange and MLrange). Further, the sit-to-stand (PStand) and turning and sit power (PTurnSit), the total time required to complete the test and the reaction time were measured.ResultsThere were no differences between the two AD stages either for ST or DT in any of the variables (p > 0.05). Nevertheless, people at both stages showed significantly lower values of PStand and PTurnSit and larger Total time and Reaction time compared to CG (p < 0.05). Further, Vrange is also lower in CDR1G than in CG (p < 0.05). The DT had a significant deleterious effect on MLDisp in all groups (p < 0.05) and on APDisp only in moderate AD for DT.ConclusionsOur findings indicate that AD patients present impairments in some key functional abilities, such as gait, turning and sitting, sit to stand, and reaction time, both in mild and moderate AD. Nevertheless, an exclusively cognitive task only influences the postural control in people with AD.