Trojaniello D.,University of Sassari |
Cereatti A.,University of Sassari |
Pelosin E.,University of Genoa |
Avanzino L.,University of Genoa |
And 4 more authors.
Journal of NeuroEngineering and Rehabilitation | Year: 2014
Background: The step-by-step determination of the spatio-temporal parameters of gait is clinically relevant since it provides an estimation of the variability of specific gait patterns associated with frequent geriatric syndromes. In recent years, several methods, based on the use of magneto-inertial units (MIMUs), have been developed for the step-by-step estimation of the gait temporal parameters. However, most of them were applied to the gait of healthy subjects and/or of a single pathologic population. Moreover, spatial parameters in pathologic populations have been rarely estimated step-by-step using MIMUs. The validity of clinically suitable MIMU-based methods for the estimation of spatio-temporal parameters is therefore still an open issue. The aim of this study was to propose and validate a method for the determination of both temporal and spatial parameters that could be applied to normal and heavily compromised gait patterns. Methods: Two MIMUs were attached above each subject's ankles. An instrumented gait mat was used as gold standard. Gait data were acquired from ten hemiparetic subjects, ten choreic subjects, ten subjects with Parkinson's disease and ten healthy older adults walking at two different gait speeds. The method detects gait events (GEs) taking advantage of the cyclic nature of gait and exploiting some lower limb invariant kinematic characteristics. A combination of a MIMU axes realignment along the direction of progression and of an optimally filtered direct and reverse integration is used to determine the stride length. Results: Over the 4,514 gait cycles analyzed, neither missed nor extra GEs were generated. The errors in identifying both initial and final contact at comfortable speed ranged between 0 and 11 ms for the different groups analyzed. The stride length was estimated for all subjects with less than 3% error. Conclusions: The proposed method is apparently extremely robust since gait speed did not substantially affect its performance and both missed and extra GEs were avoided. The spatio-temporal parameters estimates showed smaller errors than those reported in previous studies and a similar level of precision and accuracy for both healthy and pathologic gait patterns. The combination of robustness, precision and accuracy suggests that the proposed method is suitable for routine clinical use. © 2014 Trojaniello et al.
PubMed | Center for the Study of Movement and Wohl Institute for Advanced Imaging
Type: Journal Article | Journal: Journal of neurology | Year: 2015
Falls are debilitating problems that markedly impact the health-related quality of life of many patients with Parkinsons disease (PD). Numerous studies point to the role of executive function and attention in falls; however, the brain mechanisms underlying these relationships are less clear. Here, we aim to evaluate the brain mechanisms underlying the role of executive function in falls. Patients with PD who were fallers (n = 27) or non-fallers (n = 53) and 27 healthy older adults were examined in a cross-sectional study. Gray matter volumes of the caudate head and posterior putamen were evaluated, as these striatal regions play a role in the executive and the sensorimotor cortico-striatal networks, respectively. The functional connectivity of the central executive network and of the sensorimotor network was measured using intrinsic brain connectivity during resting state functional magnetic resonance imaging. Compared to non-fallers and healthy controls, fallers had lower gray matter volume in the caudate head, but not in the posterior putamen, and increased connectivity between posterior partial regions of the central executive network, with no difference within the sensorimotor network. Mediation analysis demonstrated that the relationships between caudate head gray matter volume and fall history and risk were mediated by increased connectivity within the central executive network, apparently via attentional changes. The above findings provide additional converging evidence for the involvement of executive-related brain changes in falls in PD and support the important role of attention and executive function in fall risk.
PubMed | University of Genoa and Center for the Study of Movement
Type: | Journal: Frontiers in aging neuroscience | Year: 2016
The aim of this study was to address whether deficits in the central cholinergic activity may contribute to the increased difficulty to allocate attention during gait in the elderly with heightened risk of falls. We recruited 50 participants with a history of two or more falls (33 patients with Parkinsons Disease and 17 older adults) and 14 non-fallers age-matched adults. Cholinergic activity was estimated by means of short latency afferent inhibition (SAI), a transcranial magnetic stimulation (TMS) technique that assesses an inhibitory circuit in the sensorimotor cortex and is regarded as a global marker of cholinergic function in the brain. Increased difficulty to allocate attention during gait was evaluated by measuring gait performance under single and dual-task conditions. Global cognition was also assessed. Results showed that SAI was reduced in patients with PD than in the older adults (fallers and non-fallers) and in older adults fallers with respect to non-fallers. Reduction in SAI indicates less inhibition i.e., less cholinergic activity. Gait speed was reduced in the dual task gait compared to normal gait only in our faller population and changes in gait speed under dual task significantly correlated with the mean value of SAI. This association remained significant after adjusting for cognitive status. These findings suggest that central cholinergic activity may be a predictor of change in gait characteristics under dual tasking in older adults and PD fallers independently of cognitive status.
Fasano A.,University of Western Ontario |
Herman T.,Center for the Study of Movement |
Tessitore A.,The Second University of Naples |
Strafella A.P.,University of Western Ontario |
Bohnen N.I.,University of Michigan
Journal of Parkinson's Disease | Year: 2015
Functional brain imaging techniques appear ideally suited to explore the pathophysiology of freezing of gait (FOG). In the last two decades, techniques based on magnetic resonance or nuclear medicine imaging have found a number of structural changes and functional disconnections between subcortical and cortical regions of the locomotor network in patients with FOG. FOG seems to be related in part to disruptions in the "executive-attention" network along with regional tissue loss including the premotor area, inferior frontal gyrus, precentral gyrus, the parietal and occipital areas involved in visuospatial functions of the right hemisphere. Several subcortical structures have been also involved in the etiology of FOG, principally the caudate nucleus and the locomotor centers in the brainstem. Maladaptive neural compensation may present transiently in the presence of acute conflicting motor, cognitive or emotional stimulus processing, thus causing acute network overload and resulting in episodic impairment of stepping. In this review we will summarize the state of the art of neuroimaging research for FOG. We will also discuss the limitations of current approaches and delineate the next steps of neuroimaging research to unravel the pathophysiology of this mysterious motor phenomenon. © 2015-IOS Press and the authors.
PubMed | University of Western Ontario, University of Michigan, Center for the study of Movement and The Second University of Naples
Type: Journal Article | Journal: Journal of Parkinson's disease | Year: 2015
Functional brain imaging techniques appear ideally suited to explore the pathophysiology of freezing of gait (FOG). In the last two decades, techniques based on magnetic resonance or nuclear medicine imaging have found a number of structural changes and functional disconnections between subcortical and cortical regions of the locomotor network in patients with FOG. FOG seems to be related in part to disruptions in the executive-attention network along with regional tissue loss including the premotor area, inferior frontal gyrus, precentral gyrus, the parietal and occipital areas involved in visuospatial functions of the right hemisphere. Several subcortical structures have been also involved in the etiology of FOG, principally the caudate nucleus and the locomotor centers in the brainstem. Maladaptive neural compensation may present transiently in the presence of acute conflicting motor, cognitive or emotional stimulus processing, thus causing acute network overload and resulting in episodic impairment of stepping.In this review we will summarize the state of the art of neuroimaging research for FOG. We will also discuss the limitations of current approaches and delineate the next steps of neuroimaging research to unravel the pathophysiology of this mysterious motor phenomenon.
Maidan I.,Center for the study of Movement |
Maidan I.,Rivers Laboratory |
Bernad-Elazari H.,Center for the study of Movement |
Gazit E.,Center for the study of Movement |
And 5 more authors.
Journal of Neurology | Year: 2015
Recent studies have suggested that deficits in executive function contribute to freezing of gait (FOG), an episodic disturbance common among patients with Parkinson’s disease (PD). To date, most findings provide only indirect evidence of this relationship. Here, we evaluated a more direct link between FOG and frontal lobe dysfunction. Functional, near infrared spectroscopy measured frontal activation, i.e., oxygenated hemoglobin (HbO2) levels in Brodmann area 10 before and during FOG. Eleven patients with PD and eleven healthy older adults were studied. Changes in frontal lobe activation before and during FOG that occurred during turns were determined. Altogether, 49 FOG episodes were observed—28 occurred during turns that were anticipated (i.e., the patient knew in advance that the turn was coming), 21 during unanticipated turns that were performed “abruptly”, according to the examiner’s request. During anticipated turns, HbO2 increased by 0.22 ± 0.08 µM (p = 0.004) before FOG and by an additional 0.19 ± 0.13 µM (p = 0.072) during FOG. In contrast, during unanticipated turns, HbO2 did not increase before or during FOG. HbO2 decreased by 0.32 ± 0.08 µM (p = 0.004) during turns without FOG; in healthy controls HbO2 did not change during turns. These findings support the existence of an association between FOG episodes and changes in frontal lobe HbO2. Increased activation in Brodmann area 10 before FOG, specifically during anticipated turns, highlights the connections between motor planning, information processing, and FOG. These results support the idea that alterations in executive control play a role in this debilitating motor disturbance. © 2015, Springer-Verlag Berlin Heidelberg.
News Article | November 1, 2016
A combination of virtual reality and treadmill training may prove effective in preventing dangerous falls associated with aging, Parkinson's disease, mild cognitive impairment or dementia, according to a new Tel Aviv University-Tel Aviv Sourasky Medical Center (TASMC) study published in The Lancet. According to the study's lead authors, Prof. Jeff Hausdorff and Dr. Anat Mirelman, both of TAU's Sackler School of Medicine and TASMC's Center for the Study of Movement, Cognition and Mobility, the intervention combines the physical and cognitive aspects of walking, and could be implemented in gyms, rehabilitation centers and nursing homes to improve walking skills and prevent the falls of older adults and those with movement disorders like Parkinson's disease. "Falls often start a vicious cycle with many negative health consequences," said Dr. Mirelman. "The ability of older people to negotiate obstacles can be impaired because of age-related decline in cognitive abilities like motor planning, divided attention, executive control and judgement. But current interventions typically focus almost exclusively on improving muscle strength, balance and gait. "Our approach helps improve both physical mobility and cognitive aspects that are important for safe walking," Dr. Mirelman continued. "We found that virtual reality plus treadmill training helped to reduce fall frequency and fall risk for at least six months after training -- significantly more than treadmill training alone. This suggests that our use of virtual reality successfully targeted the cognitive aspects of safe ambulation to reduce the risk of falls." The TAU-TASMC team, in collaboration with partners across Europe, collected data from 282 participants at five clinical sites in Belgium, Israel, Italy, the Netherlands and the UK between 2013 and 2015. The participants, all aged 60-90, were able to walk at least five minutes unassisted, were on stable medications and, critically, had reported at least two falls in the six months prior to the start of the study. Nearly half of all participants (130) had Parkinson's disease, and some (43) had mild cognitive impairment. Participants were assigned to treadmill training with virtual reality (146) or treadmill training alone (136). The virtual reality component consisted of a camera that captured the movement of participants' feet and projected it onto a screen in front of the treadmill, so that participants could "see" their feet walking on the screen in real time. The game-like simulation was designed to reduce the risk of falls in older adults by including real life challenges such as avoiding and stepping over obstacles like puddles or hurdles, and navigating pathways. It also provided motivation to the participants, giving them feedback on their performance and scores on the game. While the incident rate of falls was similar in the two groups prior to the intervention, six months after training the rate of falls among those who trained with VR dropped by almost 50%. In contrast, there was no significant reduction in the fall rates among subjects who did not train with the VR. "Interestingly, when we asked people if they enjoyed the treatment program, participants in the virtual reality group reported higher scores on user satisfaction questionnaires and a greater desire to continue to exercise with the 'game,'" said Prof. Hausdorff. "This suggests that the virtual reality not only led to fewer falls, it was also more likely to be used in the long-term. Exercise needs to be fun and effective if it is going to be used continually. "The biggest improvement was seen in participants with Parkinson's disease," Prof. Hausdorff continued. "It was very exciting to see such improvement in the presence of a neurodegenerative disease. Still, we need to conduct further research to verify the results and better understand why the fall rates were so responsive in the people with Parkinson's disease." "Treadmills are widely available, and the additional cost of treadmill training plus virtual reality is only about $4,500. The low cost could permit this approach to be widely used in various settings," said Dr. Mirelman. "Future studies need to examine whether treadmill training plus virtual reality could be used as part of a prevention package to treat fall risk before falls become common and before injuries occur." The research was funded by the European Commission. Tel Aviv University (TAU) is inherently linked to the cultural, scientific and entrepreneurial mecca it represents. It is one of the world's most dynamic research centers and Israel's most distinguished learning environment. Its unique-in-Israel multidisciplinary environment is highly coveted by young researchers and scholars returning to Israel from post-docs and junior faculty positions in the US. American Friends of Tel Aviv University (AFTAU) enthusiastically and industriously pursues the advancement of TAU in the US, raising money, awareness and influence through international alliances that are vital to the future of this already impressive institution.
Herman T.,Center for the Study of Movement |
Herman T.,Tel Aviv University |
Weiss A.,Center for the Study of Movement |
Brozgol M.,Center for the Study of Movement |
And 4 more authors.
Journal of Neurology | Year: 2014
Parkinson’s disease (PD) is often divided into tremor dominant (TD) and postural instability gait difficulty (PIGD) subtypes. However, objective measures of gait (e.g., stride length, variability) and balance have not been well studied in these subtypes. To better understand these motor subtypes, we objectively quantified gait and balance and their behavioral correlates. 110 patients with PD underwent a clinical evaluation and were stratified into PIGD and TD subtypes. Participants walked under single and dual task conditions while wearing a single body-fixed sensor, both “OFF” and “ON” medications and at home for 3 days. We also examined performance-based tests of mobility, balance, and fall risk. Stricter criteria were also applied, dividing the subjects into predominant representative subgroups: p-PIGD and p-TD. Both the PIGD (n = 62) and TD (n = 42) groups and the p-PIGD (n = 31) and p-TD (n = 32) subgroups were similar with respect to basic disease characteristics (e.g., disease duration, p > 0.69). Surprisingly gait speed, stride length, and variability did not differ between the PIGD and TD groups (p > 0.05). In contrast, the p-PIGD group had reduced gait speed (under single and dual task conditions), shorter strides, increased stride variability, and decreased stride regularity (regularity: p-PIGD 0.66 ± 0.10; p-TD 0.74 ± 0.08; p = 0.003). The p-PIGD group also scored worse on performance-based tests, compared to the p-TD. Clinical assessments of the disturbances seen in patients with the PIGD subtype are not consistent with objective measures; overlapping between the groups is seen in many objective features of gait and balance. These findings suggest that the proposed alternate classification scheme may be useful. © 2014, Springer-Verlag Berlin Heidelberg.
PubMed | Center for the Study of Movement, Tel Aviv University, Cognitive Medical Systems and Norwegian University of Science and Technology
Type: Journal Article | Journal: Journal of biomechanics | Year: 2016
In the present study we compared the performance of three different estimations of local dynamic stability to distinguish between the dynamics of the daily-life walking of elderly fallers and non-fallers. The study re-analyses inertial sensor data of 3-days daily-life activity originally described by Weiss et al. (2013). The data set contains inertial sensor data from 39 older persons who reported less than 2 falls and 31 older persons who reported two or more falls the previous year. 3D-acceleration and 3D-velocity signals from walking epochs of 50s were used to reconstruct a state space using three different methods. Local dynamic stability was estimated with the algorithms proposed by Rosenstein et al. (1993), Kantz (1994), and Ihlen et al. (2012a). Median s assessed by Ihlens and Kantz algorithms discriminated better between elderly fallers and non-fallers (highest AUC=0.75 and 0.73) than Rosensteins algorithm (highest AUC=0.59). The present results suggest that the ability of to distinguish between fallers and non-fallers is dependent on the parameter setting of the chosen algorithm. Further replication in larger samples of community-dwelling older persons and different patient groups is necessary before including the suggested parameter settings in fall risk assessment and prediction models.
PubMed | Center for the Study of Movement, Tel Aviv University and Norwegian University of Science and Technology
Type: | Journal: BioMed research international | Year: 2015
The present study compares phase-dependent measures of local dynamic stability of daily life walking with 35 conventional gait features in their ability to discriminate between community-dwelling older fallers and nonfallers. The study reanalyzes 3D-acceleration data of 3-day daily life activity from 39 older people who reported less than 2 falls during one year and 31 who reported two or more falls. Phase-dependent local dynamic stability was defined for initial perturbation at 0%, 20%, 40%, 60%, and 80% of the step cycle. A partial least square discriminant analysis (PLS-DA) was used to compare the discriminant abilities of phase-dependent local dynamic stability with the discriminant abilities of 35 conventional gait features. The phase-dependent local dynamic stability at 0% and 60% of the step cycle discriminated well between fallers and nonfallers (AUC = 0.83) and was significantly larger (p < 0.01) for the nonfallers. Furthermore, phase-dependent discriminated as well between fallers and nonfallers as all other gait features combined. The present result suggests that phase-dependent measures of local dynamic stability of daily life walking might be of importance for further development in early fall risk screening tools.