Gait and Falls in Benign Paroxysmal Positional Vertigo: A Systematic Review and Meta-analysis.

BACKGROUND AND PURPOSE: Benign paroxysmal positional vertigo (BPPV) is one of the most common vestibular disorders, and is treated effectively with particle repositioning maneuvers (PRM). The aim of this study was to assess the influence of BPPV and treatment effects of PRM on gait, falls, and fear of falling. METHODS: Three databases and the reference lists of included articles were systematically searched for studies comparing gait and/or falls between (1) people with BPPV (pwBPPV) and controls and (2) pre- and posttreatment with PRM. The Joanna Briggs Institute critical appraisal tools were used to assess risk of bias. RESULTS: Twenty of the 25 included studies were suitable for meta-analysis. Quality assessment resulted in 2 studies with high risk of bias, 13 with moderate risk, and 10 with low risk. PwBPPV walked slower and demonstrated more sway during tandem walking compared with controls. PwBPPV also walked slower during head rotations. After PRM, gait velocity during level walking increased significantly, and gait became safer according to gait assessment scales. Impairments during tandem walking and walking with head rotations did not improve. The number of fallers was significantly higher for pwBPPV than for controls. After treatment, the number of falls, number of pwBPPV who fell, and fear of falling decreased. DISCUSSION AND CONCLUSIONS: BPPV increases the odds of falls and negatively impacts spatiotemporal parameters of gait. PRM improves falls, fear of falling, and gait during level walking. Additional rehabilitation might be necessary to improve gait while walking with head movements or tandem walking.Video Abstract available for more insights from the authors (see the Supplemental Digital Content Video, available at: http://links.lww.com/JNPT/A421 ).

Cycling: how can we activate care-dependent older adults with a mild cognitive impairment?

PURPOSE: In residential care, 50% of older adults are sedentary in most of their time, regardless of the positive impact of physical exercise on health. This study analysed whether television images positively impact the motivation and exercise intensity of cycling exercises of older adults in residential care. METHODS: In this randomised controlled cross-over study, 10 residential older adults (mean age 85.0 ± 5.7 years) with Mild Cognitive Impairment (MCI) participated in 3 different cycling exercise interventions (TV off, TV turned on the National Geographic channel (NG) and TV with MemoRide software (Activ84Health®, Leuven, Belgium) (MR) (cybercycling)) compared with a rest condition. RESULTS: The participants cycled significantly more distance during NG compared with TVoff (p = 0.024). In comparison to the rest condition, the mean heart rate was significantly higher in all exercise conditions while the maximal heart rate was only higher during NG (p = 0.022). There was no difference in the Borg scale between the different exercise interventions. Interest and enjoyment scored significantly higher during NG (p = 0.014) and MR (p = 0.047) compared to the rest condition and in the NG versus TVoff (p = 0.018). No significant differences were observed in the emotions of the participants. CONCLUSIONS: This study has shown indications that the addition of television images may increase the exercise intensity and motivation to exercise in residential older adults with MCI. However, the overall levels of physical activity were insufficient to meet the recommendations for moderate-intense aerobic exercise according to the International Association of Gerontology and Geriatrics and Global Ageing Research Network.Implications for rehabilitationCycling in front of a television increases the exercise volume and motivation to exercise in residential (pre)frail older adults with MCICybercycling had no additional effect in comparison to television images not linked to the exercise.Even with television images (pre)frail older adults with MCI did not meet the recommendations for moderate-intense aerobic exercise for residential older adults according to the IAGG-GARN.

The effect of constraining mediolateral ankle moments and foot placement on the use of the counter-rotation mechanism during walking.

During walking, the center of mass (CoM) position can be controlled relative to the base of support by shifts of the center of pressure through modulation of foot placement and ankle moments (CoP-mechanism). An additional mechanism is the counter-rotation mechanism, i.e. changing the angular momentum of segments around the CoM to change the direction of the ground reaction force. It is unknown if, and how, humans use the counter-rotation mechanism to accelerate the CoM during walking and how this interacts with the CoP-mechanism. Thirteen healthy adults walked on a treadmill, while full-body kinematic and force plate data were obtained. The contributions of the CoP and the counter-rotation mechanisms to CoM-acceleration during steady-state walking, walking on LesSchuh (i.e. constraining mediolateral CoP shifts underneath the stance foot) and walking on LesSchuh at 50% of normal step width, constraining both foot placement and ankle mechanisms (LesSchuh50%) were calculated. The within-stride variance in CoM-acceleration due to the CoP-mechanism was smaller and the within-stride variance in CoM-acceleration due to the counter-rotation mechanism was larger during LesSchuh50% compared to steady-state walking. This suggests that the counter-rotation mechanism is used to stabilize gait when needed, but the CoP-mechanism was the main contributor to the total CoM-acceleration. The use of the counter-rotation mechanism may be limited, because angular accelerations ultimately need to be reversed and because of interference with other task constraints, such as head stabilization and preventing interference with the gait pattern.

Frailty Test Battery Development including Physical, Socio-Psychological and Cognitive Domains for Cardiovascular Disease Patients: A Preliminary Study.

Frailty is an age-related decline in physical, socio-psychological and cognitive function that results in extreme vulnerability to stressors. Therefore, this study aimed to elucidate which tests have to be selected to detect frailty in a comprehensive and feasible manner in cardiovascular disease (CVD) patients based on multivariate regression and sensitivity/specificity analyses. Patients (n = 133, mean age 78 ± 7 years) hospitalised for coronary revascularisation or heart failure (HF) were examined using the Fried and Vigorito criteria, together with some additional measurements. Moreover, to examine the association of frailty with 6-month clinical outcomes, hospitalisations and mortality up to 6 months after the initial hospital admission were examined. Some level of frailty was detected in 44% of the patients according to the Vigorito criteria and in 65% of the patients according to the Fried criteria. Frailty could best be detected by a score based on: sex, Mini Nutritional Assessment (MNA), Katz scale, timed up-and-go test (TUG), handgrip strength, Mini-Mental State Examination (MMSE), Geriatric Depression Scale (GDS-15) and total number of medications. Frailty and specific markers of frailty were significantly associated with mortality and six-month hospitalisations. We thus can conclude that, in patients with CVD, sex, MNA, Katz scale, TUG, handgrip strength, MMSE, GDS-15 and total number of medications play a key role in detecting frailty, assessed by a new time- and cost-efficient test battery.

Effects of age and surface instability on the control of the center of mass.

During standing, posture can be controlled by accelerating the Center of Mass (CoM) through shifting the center of pressure (CoP) within the base of support by applying ankle moments ("CoP mechanism"), or through the "counter-rotation mechanism", i.e., changing the angular momentum of segments around the CoM to change the direction of the ground reaction force. Postural control develops over the lifespan; at both the beginning and the end of the lifespan adequate postural control appears more challenging. In this study, we aimed to assess mediolateral balance performance and the related use of the postural control mechanisms in children, older adults and younger adults when standing on different (unstable) surfaces. Sixteen pre-pubertal children (6-9y), 17 younger adults (18-24y) and eight older adults (65-80y) performed bipedal upright standing trials of 16 s on a rigid surface and on three balance boards that could freely move in the frontal plane, varying in height (15-19 cm) of the surface of the board above the point of contact with the floor. Full body kinematics (16 segments, 48 markers, using SIMI 3D-motion analysis system (GmbH) and DeepLabCut and Anipose) were retrieved. Performance related outcome measures, i.e., the number of trials with balance loss and the Root Mean Square (RMS) of the time series of the CoM acceleration, the contributions of the CoP mechanism and the counter-rotation mechanism to the CoM acceleration in the frontal plane and selected kinematic measures, i.e. the orientation of the board and the head and the Mean Power Frequency (MPF) of the balance board orientation and the CoM acceleration were determined. Balance loss only occurred when standing on the highest balance board, twice in one older adult once in one younger adult. In children and older adults, the RMS of the CoM accelerations were larger, corresponding to poorer balance performance. Across age groups and conditions, the contribution of the CoP mechanism to the total CoM acceleration was much larger than that of the counter-rotation mechanisms, ranging from 94% to 113% vs 23% to 38% (with totals higher than 100% indicating opposite effects of both mechanisms). Deviations in head orientation were small compared to deviations in balance board orientation. We suggest that the CoP mechanism is dominant, since the counter-rotation mechanism would conflict with stabilizing the orientation of the head in space.

Effect of age on treatment outcomes in benign paroxysmal positional vertigo: A systematic review.

BACKGROUND: Benign paroxysmal positional vertigo (BPPV) can lead to an increased fall risk in older adults. Therefore, we examined the influence of age on the effectiveness of canalith-repositioning procedures (CRPs) for the treatment of BPPV. METHODS: Pubmed, Web of Science, and the bibliographies of selected articles were searched for studies conducted before September 2020 that examined the effectiveness of treatments for BPPV in various age groups. Meta-analyses were performed to compare treatment effectiveness and recurrence rates for younger and older adults. Odds ratios were calculated in a random-effects model. Mean differences were calculated using a fixed-effects model. A significance level of p < 0.05 (95% confidence interval) was set. The risk of bias and the methodological quality of all included articles were examined. RESULTS: Forty-five studies were retrieved after full-text screening, of which 29 studies were included for a qualitative review. The remaining 16 studies were eligible for inclusion in the meta-analysis (3267 participants with BPPV). The success rate of a single CRP was higher in the younger group (72.5% vs. 67%, p < 0.001). An average of 1.4 and 1.5 CRPs was needed for complete recovery in the younger and older groups, respectively (p = 0.02). However, global treatment success did not differ between these groups (97.5% vs. 94.6%, p = 0.41). The recurrence rate was higher in the older population (23.2% vs. 18.6%, p = 0.007). CONCLUSIONS: Although more CRPs are needed, the rate of complete recovery in older adults is similar to that observed in younger adults.

Modelling and identification of characteristic kinematic features preceding freezing of gait with convolutional neural networks and layer-wise relevance propagation.

BACKGROUND: Although deep neural networks (DNNs) are showing state of the art performance in clinical gait analysis, they are considered to be black-box algorithms. In other words, there is a lack of direct understanding of a DNN's ability to identify relevant features, hindering clinical acceptance. Interpretability methods have been developed to ameliorate this concern by providing a way to explain DNN predictions. METHODS: This paper proposes the use of an interpretability method to explain DNN decisions for classifying the movement that precedes freezing of gait (FOG), one of the most debilitating symptoms of Parkinson's disease (PD). The proposed two-stage pipeline consists of (1) a convolutional neural network (CNN) to model the reduction of movement present before a FOG episode, and (2) layer-wise relevance propagation (LRP) to visualize the underlying features that the CNN perceives as important to model the pathology. The CNN was trained with the sagittal plane kinematics from a motion capture dataset of fourteen PD patients with FOG. The robustness of the model predictions and learned features was further assessed on fourteen PD patients without FOG and fourteen age-matched healthy controls. RESULTS: The CNN proved highly accurate in modelling the movement that precedes FOG, with 86.8% of the strides being correctly identified. However, the CNN model was unable to model the movement for one of the seven patients that froze during the protocol. The LRP interpretability case study shows that (1) the kinematic features perceived as most relevant by the CNN are the reduced peak knee flexion and the fixed ankle dorsiflexion during the swing phase, (2) very little relevance for FOG is observed in the PD patients without FOG and the healthy control subjects, and (3) the poor predictive performance of one subject is attributed to the patient's unique and severely flexed gait signature. CONCLUSIONS: The proposed pipeline can aid clinicians in explaining DNN decisions in clinical gait analysis and aid machine learning practitioners in assessing the generalization of their models by ensuring that the predictions are based on meaningful kinematic features.

Frailty is highly prevalent in specific cardiovascular diseases and females, but significantly worsens prognosis in all affected patients: A systematic review.

Cardiologists are more often confronted with older (>60 years) cardiovascular disease (CVD) patients. These patients have particular needs in clinical care because, for example, of frailty. However, it remains to be established what is the prevalence of frailty in different CVD's and how it relates to mortality. In this systematic review studies were included if they: (i) examined subjects (men and women) aged ≥60 years who suffered from any CVD with or without cardiac surgery, (ii.) examined the presence of frailty with a well-defined frailty tool and (iii.) reported prevalence rates of frailty. From thirty studies comprising 96.841 participants, it is found that 1. Frailty is highly common in older patients with CVD (in particular in females (approximately 1.6 times more than in males), in heart failure (up to 80 % of patients) and aortic valve disease (up to 74 % of patients)), and 2. Frailty is related to a 2.5-3.5-fold elevated mortality risk, even in patients with less severe CVD (e.g. percutaneous coronary intervention). Moreover, there is a lack of consistency on how to assess frailty as up to 20 different tools/assessment batteries are currently used. It is concluded that frailty should be assessed in all older CVD patients in a uniform manner to enhance clinical care and outcomes.

A data-driven approach for detecting gait events during turning in people with Parkinson's disease and freezing of gait.

BACKGROUND: Manual annotation of initial contact (IC) and end contact (EC) is a time consuming process. There are currently no robust techniques available to automate this process for Parkinson's disease (PD) patients with freezing of gait (FOG). OBJECTIVE: To determine the validity of a data-driven approach for automated gait event detection. METHODS: 15 freezers were asked to complete several straight-line and 360 degree turning trials in a 3D gait laboratory during the off-period of their medication cycle. Trials that contained a freezing episode were indicated as freezing trials (FOG) and trials without a freezing episode were termed as functional gait (FG). Furthermore, the highly varied gait data between onset and termination of a FOG episode was excluded. A Temporal Convolutional Neural network (TCN) was trained end-to-end with lower extremity kinematics. A Bland-Altman analysis was performed to evaluate the agreement between the results of the proposed model and the manual annotations. RESULTS: For FOG-trials, F1 scores of 0.995 and 0.992 were obtained for IC and EC, respectively. For FG-trials, F1 scores of 0.997 and 0.999 were obtained for IC and EC, respectively. The Bland-Altman plots indicated excellent timing agreement, with on average 39% and 47% of the model predictions occurring within 10 ms from the manual annotations for FOG-trials and FG-trials, respectively. SIGNIFICANCE: These results indicate that our data-driven approach for detecting gait events in PD patients with FOG is sufficiently accurate and reliable for clinical applications.

The Impact of Different Types of Exercise Training on Peripheral Blood Brain-Derived Neurotrophic Factor Concentrations in Older Adults: A Meta-Analysis.

BACKGROUND: As the prevalence of neurodegenerative diseases (such as dementia) continues to increase due to population aging, it is mandatory to understand the role of exercise for maintaining/improving brain health. OBJECTIVES: To analyse the impact of aerobic, strength and combined aerobic/strength exercise training on peripheral brain-derived neurotrophic factor (BDNF) concentrations in older adults (minimum age 60 years). METHODS: This meta-analysis adhered to PRISMA guidelines. Inclusion criteria were: (i) studies with subjects aged ≥ 60 years, (ii) completing a single exercise bout or an exercise programme, with (iii) measurements of blood BDNF in the periphery; (iv) with comparison between (a) an intervention and control group or (b) two intervention groups, or (c) pre- and post-measurements of an exercise intervention without control group. Studies with specific interest in known chronic co-morbidities or brain diseases affecting the peripheral and/or central nervous system, except for dementia, were excluded. RESULTS: In general, peripheral blood BDNF concentrations increased significantly after a single aerobic/strength exercise bout (Z = 2.21, P = 0.03) as well as after an exercise programme (Z = 4.72, P < 0.001). However, when comparing the different types of exercise within these programmes, the increase in the peripheral BDNF concentrations was significant after strength training (Z = 2.94, P = 0.003) and combined aerobic/strength training (Z = 3.03, P = 0.002) but not after (low-to-moderate intense) aerobic exercise training (Z = 0.82, P = 0.41). CONCLUSIONS: Based on current evidence, to increase the peripheral blood BDNF concentrations in older adults, strength training and combined aerobic/strength training is effective. More studies are needed to examine the impact of aerobic exercise training.

A physical exercise program using music-supported video-based training in older adults in nursing homes suffering from dementia: a feasibility study.

BACKGROUND: Motivation towards an exercise program is higher in a small group setting in comparison to individual therapy. Due to attentional problems, group exercises are difficult for people with Alzheimer disease (AD). This study evaluates the feasibility of a music-supported video-based group exercise program in older adults suffering from AD. METHODS: Five participants with moderate AD were recruited from a nursing home. A progressive physical exercise program using a video-based training with musical accompaniment was performed and digitally recorded to investigate the adherence and performed accuracy of the exercises. RESULTS: The overall participation during the exercises was 84.1%. The quality of the performance was for all exercises above the cut-off scores. CONCLUSION: A music-supported video-based group exercise program is feasible in persons with AD. The participants were motivated and the expectations towards the program increased over time. Music seemed an important factor for attention in participants with AD.

Turning problems and freezing of gait in Parkinson's disease: a systematic review and meta-analysis.

Objective: To understand the differences of step and turn parameters between freezers and non-freezers during turning and determine the influence of turn angle and turn characteristics on freezing of gait.Data sources: PubMed and Web of Science were searched from the earliest data available to August 2017.Study selection: Case-control studies that examined the differences in turning while walking between freezers and non-freezers were included. Two reviewers selected studies independently.Data extraction: Methodological quality was evaluated by two independent reviewers using the STROBE checklist for case-control studies. Mean differences and 95% confidence intervals were calculated from pooled data for turn duration, peak turn velocity, number of steps and cadence. Center of mass deviation, segmental rotation, phase coordination and freezing of gait frequency were also extracted. When possible, different turning angles or spatial confounds were compared.Data synthesis: Sixteen studies met the inclusion criteria. Freezing of gait occurred in 38.2% of the freezers. Freezing appeared most frequently at the end of a turn and at the inner leg of the turn cycle. The meta-analysis revealed that turning in freezers was characterized by an increased turn duration, cadence and number of steps and a decreased peak turn velocity. Qualitative analysis showed that results concerning step width, step length and step time variability were inconsistent. Turning was characterized by an increased head-pelvis coupling and worse coordination in freezers compared to non-freezers. A decreased medial deviation of the center of mass was present prior to a freezing episode.Conclusions: Both step and rotational parameters differed in freezers compared to non-freezers while turning. These differences increased with increasing task complexity (i.e., larger turning angle or spatial confounds during turning). The results suggest that improving axial rotation could be a valuable rehabilitation target to ameliorate freezing.Implications for rehabilitationPatients with freezing of gait turn with a larger arc and a smaller angle compared to non-freezing patientsFreezing-related turning deficits have both spatiotemporal and rotational motor control componentsImproving axial rotation could be a novel rehabilitation target to ameliorate freezing.

The effect of cognitive-motor dual task training with the biorescue force platform on cognition, balance and dual task performance in institutionalized older adults: a randomized controlled trial.

[Purpose] This study investigates whether cognition, balance and dual task performance in institutionalized older adults improves by a virtual reality dual task training. [Subjects and Methods] Randomized controlled trial; Twenty institutionalized older adults with mild cognitive impairment (13 female, 7 male; average age, 87.2 ± 5.96 years) were randomized to the intervention (i.e. Virtual reality dual-task training using the BioRescue) or control group (no additional training). The intervention group took part in a 6-week training program while the elderly in the control group maintained their daily activities. Balance was measured with the Instrumented Timed Up-and-Go Test with and without a cognitive task. The Observed Emotion Rating Scale and Intrinsic Motivation Inventory were administered to evaluate the emotions and motivation regarding the exergaming program. [Results] The intervention group improved significantly on the total Timed Up-and-Go duration and the turn-to-sit duration during single-task walking in comparison to the control group who received no additional training. Participants found the virtual reality dual task training pleasant and useful for their concentration, memory and balance. Pleasure and alertness were the two emotions which were mostly seen during the intervention. [Conclusion] The BioRescue is a pleasant and interesting treatment method, well suited for institutionalized older adults in need of lifelong physical therapy.

Influence of Cueing and an Attentional Strategy on Freezing of Gait in Parkinson Disease During Turning.

BACKGROUND AND PURPOSE: Individuals with Parkinson disease exhibit decreased axial head-pelvis rotation. Consequently, they turn more en bloc than healthy controls, which may contribute to freezing during turning. We wanted to understand the influence of auditory cueing and an attentional strategy on turning and how this related to freezing of gait (FOG). METHODS: Fifteen participants with Parkinson disease and FOG were asked to turn 180° during baseline condition, unilateral cueing, and an attentional strategy prompting to start the turn with head rotation first. FOG occurrence, axial rotation, center of mass (COM) deviation, knee-flexion amplitude, and total turn velocity were measured using 3D motion analysis while off-medication. Normal reference values were obtained from 14 age-matched controls. RESULTS: Thirty-nine FOG episodes occurred in 5 participants. FOG occurred in 52.8% of baseline trials compared with 34.6% of trials using the head-first strategy, and 3.8% of the auditory cueing trials. During the head first strategy, the initiation of head, trunk, and pelvic rotation as well as the head-pelvis separation resembled turning patterns of healthy controls, but the COM shift to the inside of the turn was exaggerated. By contrast, during cueing, turning became more en bloc, with decreased head-pelvis separation and knee-flexion amplitude. DISCUSSION AND CONCLUSIONS: Cueing reduced FOG but did not correct axial movement deficits. The head-first strategy improved head-pelvis dissociation but had only limited effects on FOG. These results suggest that axial and COM deviation impairments are not directly related to FOG but may rather indicate a compensatory mechanism. Cueing reinforced the en-bloc movement and might as such help prevent FOG by triggering an alternative neural mechanism for movement generation.Video Abstract available for more insights from the authors (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A163).

Head-pelvis coupling is increased during turning in patients with Parkinson's disease and freezing of gait.

Turning is the most important trigger for freezing of gait (FOG). The aim of this study was to investigate the relationship between impaired head-pelvis rotation during turning and FOG. Head, trunk, and pelvic rotation were measured at onset and throughout a 180-degree turn in 13 freezers and 14 nonfreezers (OFF medication). We also studied 14 controls at preferred and slow speed to investigate the influence of turn velocity on axial rotation. Location and duration of FOG episodes were defined during the turn. At turning onset, head rotation preceded thorax and pelvic rotation in all groups, but this craniocaudal sequence disappeared when FOG occurred. Maximum head-pelvis separation was significantly greater in controls, compared to freezers and nonfreezers (35.4 versus 25.7 and 27.3 degrees; P < 0.01), but this finding was speed dependent. Timing of maximum head-pelvis separation was delayed in freezers, compared to nonfreezers and controls, irrespective of turn velocity. This delay was correlated with increased neck rigidity (R = 0.62; P = 0.02) and worsened during FOG trials. FOG occurred more often at the end of the turn, when difference in rotation velocity between head and pelvis was greatest. Even after controlling for speed and disease severity, turning in freezers was characterized by delayed head rotation and a closer coupling between head and pelvis, especially in turns where FOG occurred. These changes may be attributed to delayed preparation for the change in walking direction and, as such, contribute to FOG. © 2013 Movement Disorder Society.

Impaired implicit sequence learning in Parkinson's disease patients with freezing of gait.

OBJECTIVE: Freezing of gait (FOG) in Parkinson's disease (PD) may involve specific impairments in acquiring automaticity under working memory load. This study examined whether implicit sequence learning, with or without a secondary task, is impaired in patients with FOG. METHOD: Fourteen freezers (FRs), 14 nonfreezers (nFRs), and 14 matched healthy controls (HCs) performed a serial reaction time (SRT) task with a deterministic stimulus sequence under single-task (ST) and dual-task (DT) conditions. The increase in reaction times (RTs) for random compared with sequenced blocks was used as a measure of implicit sequence learning. Neuropsychological tests assessing global cognitive functioning and executive dysfunction were administered in order to investigate their relation to sequence learning. RESULTS: nFRs and HCs showed significant implicit sequence learning effects (p < 0.001). FRs demonstrated a tendency to learn sequence-specific information in the SRT-ST task (p = 0.07) but not in the SRT-DT task (p = 0.69). Severity of FOG, however, correlated positively with SRT-DT task performance (r = -0.56; p < 0.05). CONCLUSIONS: The present results suggest that PD patients suffering from FOG pathology exhibit a specific impairment in the acquisition of automaticity. When working memory capacity is supplementarily loaded by adding a DT, sequence learning in FRs becomes increasingly impaired. These findings indicate that therapies should focus on extensive training in acquiring novel motor activities and reducing working memory load to improve learning in FOG.

Explaining freezing of gait in Parkinson's disease: motor and cognitive determinants.

Freezing of gait (FOG) is part of a complex clinical picture in Parkinson's disease (PD) and is largely refractory to standard care. Diverging hypotheses exist about its origins, but a consolidated view on what determines FOG is lacking. The aim of this study was to develop an integrative model of FOG in people with PD. This cross-sectional study included 51 Parkinson subjects: 24 patients without FOG and 27 with FOG matched for age, gender, and disease severity. Subjects underwent an extensive clinical test battery evaluating general disease characteristics, gait and balance, nongait freezing, and cognitive functions. The relative contribution of these outcomes to FOG was determined using logistic regression analysis. The combination of the following four independent contributors provided the best explanatory model of FOG (R(2) = 0.49): nongait freezing; levodopa equivalent dose (LED); cognitive impairment; and falls and balance problems. The model yields a high-risk profile for FOG (P > 95%) when Parkinson patients are affected by at least one type of nongait freezing (e.g., freezing of other repetitive movements), falls or balance problems during the last 3 months, and a Scales for Outcomes in Parkinson's Disease-Cognition score below 28. A high LED further increases the risk of FOG to 99%. Nongait freezing, increased dopaminergic drug dose, cognitive deficits, and falls and balance problems are independent determinants of FOG in people with PD and may play a synergistic role in its manifestation.

Abnormalities and cue dependence of rhythmical upper-limb movements in Parkinson patients with freezing of gait.

BACKGROUND: Freezing of gait (FOG) is a significant clinical problem in Parkinson disease (PD). Similar freezing-like episodes occur during finger movements, but little is known about ongoing motor problems during repetitive hand movements. OBJECTIVE: To investigate if the regulation of bimanual movements is impaired in those with FOG and if withdrawal of an auditory cue amplifies this problem. METHODS: A total of 23 PD patients (11 with and 12 without FOG) and 11 controls (CTRLs) performed repetitive finger movements, either externally paced or following cue withdrawal. Movement frequency, amplitude, and coordination pattern were manipulated. The stability and accuracy of movement were evaluated after exclusion of freezing trials. RESULTS: With auditory pacing present, movement performance was comparable between groups. Following cue withdrawal, motor control deteriorated in those with FOG, resulting in smaller and less stable amplitudes, hastened and more variable frequency, and decreased coordination stability. Conversely, the performance of those without FOG remained mostly similar to that of CTRLs. CONCLUSIONS: Compared with those without FOG, those with FOG show greater continuous dyscontrol of bimanual movements, similar to the continuous timing and scaling difficulties during locomotion. Those with FOG also benefit from auditory cueing during upper-limb movements, but these are highly cue dependent. This implies that internal timekeeping functions are more disturbed in those with FOG, who may require rehabilitation strategies for repetitive upper-extremity tasks that include cueing and imagery.

Freezing in Parkinson's disease: a spatiotemporal motor disorder beyond gait.

Freezing of gait (FOG) is an incapacitating problem in Parkinson's disease that is difficult to manage therapeutically. We tested the hypothesis that impaired rhythm and amplitude control is a common mechanism of freezing which is also present during other rhythmic tasks. Therefore, we compared the occurrence and spatiotemporal profiles of freezing episodes during upper limb motion, lower limb motion, and FOG. Eleven freezers, 12 non-freezers, and 11 controls performed a rhythmic bilateral finger movement task. The triggering effect of movement speed, amplitude, and coordination pattern was evaluated. Regression slopes and spectral analysis addressed the spatial and temporal kinematic changes inherent to freezing episodes. The FOG Questionnaire score significantly predicted severity of upper limb freezing, present in 9 freezers, and of foot freezing, present in 8 freezers. Similar to gait, small-amplitude movements tended to trigger upper limb freezing, which was preceded by hastened movement and a strong amplitude breakdown. Upper limb freezing power spectra were broadband, including increased energy in the "freeze band" (3-8 Hz). Contrary to FOG, unilateral upper limb freezing was common and occurred mainly on the disease-dominant side. The findings emphasize that a core motor problem underlies freezing which can affect various movement effectors. This deficit may originate on the disease-dominant body side and interfere with amplitude and timing regulation during repetitive limb movements. These results may shift current thinking on the origins of freezing as being not exclusively a gait failure.

Freezing of gait in Parkinson disease is associated with impaired conflict resolution.

BACKGROUND: Freezing of gait (FOG) in Parkinson disease (PD) may involve executive dysfunction. This study examined whether executive functioning and attention are more affected in patients with FOG compared with those without and determined whether these processes are influenced by anti-Parkinson medication. METHODS: A total of 11 PD patients with FOG, 11 without FOG, and 10 healthy control subjects, matched for age, gender, and education, participated. General motor, mental and cognitive screening tests, as well as specific neuropsychological assessment of executive functions and the Attention Network Test (ANT) were administered. The ANT was conducted in both ON and OFF phases in a counterbalanced design to determine medication-specific effects. RESULTS: FOG showed a clear association with impairment in the executive control network for conflict resolution (inhibition of unwanted responses and impaired response selection), compared with nonfreezers and healthy controls, F(2, 28) = 5.41, P = .01. Orienting and alerting function did not differ between groups, F < 1. Other executive functions, such as abstract problem solving and mental flexibility were not associated with FOG (P > .10). Anti-Parkinson medication did not ameliorate conflict resolution (P > .10), although orienting attention improved with medication, F(1, 17) = 9.81, P < .01. CONCLUSIONS: This study shows an association between impaired conflict resolution and FOG, important in understanding the interplay between cognitive and motor problems, which can lead to specific rehabilitation strategies.