Chiara Iacovelli

Prefrontal cortex as a compensatory network in ataxic gait: A correlation study between cortical activity and gait parameters

PURPOSE To investigate whether prefrontal cortex (PFC) functioning during ataxic gait is linked to compensatory mechanisms or to the typical intra-subject variability of the ataxic gait. METHODS Nineteen patients with chronic ataxia and fifteen healthy subjects were evaluated. The subjects were requested to walk along a straight distance of 10 meters while PFC oxygenation and gait parameters were assessed. PFC activity was evaluated by NIRO-200 while gait analysis was performed by the SMART-D500. To investigate the intra-subject variability of gait, we calculated the coefficient of multiple correlation (CMC) of the hip, knee and ankle kinematic waveforms furthermore, we evaluated the step width. RESULTS We observed a positive correlation between PFC bilateral oxygenation changes and the step width (r = 0.54; p = 0.02 for the right PFC, and r = 0.50; p = 0.03 for the left PFC). No correlation was found between PFC activity and CMC of the hip, knee and ankle waveforms. CONCLUSIONS Our results suggest that PFC activity is linked to gait compensatory mechanisms more than to the variability of the joint kinematic parameters caused by a defective cerebellar control.

Small-World Characteristics of Cortical Connectivity Changes in Acute Stroke

Background. After cerebral ischemia, disruption and subsequent reorganization of functional connections occur both locally and remote to the lesion. Recently, complexity of brain connectivity has been described using graph theory, a mathematical approach that depicts important properties of complex systems by quantifying topologies of network representations. Functional and dynamic changes of brain connectivity can be reliably analyzed via electroencephalography (EEG) recordings even when they are not yet reflected in structural changes of connections. Objective. We tested whether and how ischemic stroke in the acute stage may determine changes in small-worldness of cortical networks as measured by cortical sources of EEG. Methods. Graph characteristics of EEG of 30 consecutive stroke patients in acute stage (no more than 5 days after the event) were examined. Connectivity analysis was performed using eLORETA in both hemispheres. Results. Network rearrangements were mainly detected in delta, theta, and alpha bands when patients were compared with healthy subjects. In delta and alpha bands similar findings were observed in both hemispheres regardless of the side of ischemic lesion: bilaterally decreased small-worldness in the delta band and bilaterally increased small-worldness in the alpha2 band. In the theta band, bilaterally decreased small-worldness was observed only in patients with stroke in the left hemisphere. Conclusions. After an acute stroke, brain cortex rearranges its network connections diffusely, in a frequency-dependent modality probably in order to face the new anatomical and functional frame.

Trunk-lower limb coordination pattern during gait in patients with ataxia.

OBJECTIVE Although deficit of coordination between the upper and lower body segments might play an important role in impairing gait and stability in ataxic patients, this deficit has not been investigated in subjects with ataxia so far. To evaluate the coordination between trunk and thigh in a sample of patients with ataxia compared with healthy controls and to correlate the coordination measures with the clinical severity. DESIGN Prospective observational study. SUBJECTS Sixteen patients with degenerative cerebellar ataxia and sixteen age- and sex-matched controls were studied. METHODS We assessed the coordination on the sagittal plane between trunk and thigh, considered as rigid segments, by the continuous relative phase (CRP) method. We used the coefficient of multiple correlation (CMC) to measure the within-subject (CMCWS) variability, and the SARA scale to assess clinical severity. RESULTS CRP curves are dissimilar between ataxic patients and controls, the former showing a chaotic behavior compared to the well-shaped CRP curves observed in the latter. Trunk-thigh coordination has a higher within-subject variability in ataxic patients (median CMCWS: 0.53 for patients, 0.89 for controls, p<0.001). We also found that the CMCWS of the CRP curves negatively correlates with the gait (ρ: -0.565, p: 0.023) and stance (ρ: -0.567, p: 0.022) sub-scores and the total score of the SARA scale (ρ: -0.711, p: 0.002). CONCLUSIONS Ataxia shows a deficit of spatio-temporal coordination between trunk and thigh. Such a deficit is correlated with the degree of the clinical impairment indicating an important role of inter-segmental coordination in determining the severity of ataxia.

Idiopathic inflammatory myopathies evaluated by near‐infrared spectroscopy

In this study we evaluated whether near‐infrared spectroscopy (NIRS) can determine the metabolic patterns of dermatomyositis (DM), polymyositis (PM), and inclusion‐body myositis (IBM).

Efficacy of Robotic-Assisted Gait Training in chronic stroke patients: Preliminary results of an Italian bi-centre study

BACKGROUND The gait recovery is a realist goal in the rehabilitation of almost Stroke patients. Over the last years, the introduction of robotic technologies in gait rehabilitation of stroke patients has had a greatest interest. OBJECTIVE The aim of this study was to evaluate efficacy of Robotic Gait Training (RGT) in chronic stroke patients. METHODS Fourteen chronic stroke patients were divided into two groups. Six patients received RGT, eight patients received traditional gait rehabilitation. Patients were assessed with clinical scales, as well as with gait analysis, at the beginning and at the end of the treatment. RESULTS Significant changes in some clinical scales for both the groups were detected. In the robotic group, patients showed higher percentage changes in the MRC scale (p = 0.020), in the 6MWT (p = 0.043) and in the Ashworth scale (hip: p = 0.008; knee: p = 0.043; ankle: p = 0.043) when compared with the traditional group. With respect to the gait analysis, we did not found any difference neither in the within-group analysis, nor in the between-group analysis. CONCLUSIONS Both rehabilitation treatments do not change the compensatory strategies in chronic patients but the RGT offers to the patients a more intensive and controlled gait training increasing the gait endurance and decreasing spasticity in the lower limb.

Use of a Virtual-Technological Sailing Program to Prepare Children With Disabilities for a Real Sailing Course Effects on Balance and Quality of Life

Sailing might produce a positive effect on a patient’s general health and become an integrated part of rehabilitation. Our hypothesis was that a specific technological rehabilitation program might be used to prepare a group of disabled subjects for sailing. Seventeen patients (age range: 9-20) with impairments in motor coordination and balance and 15 healthy subjects participated in the study. The study was divided into the virtual-technological sailing phase, theory-practice phase, and sports phase. Proprioceptive platforms were used to evaluate balance, and the Child Health Questionnaire–PF50 was used to evaluate quality of life. Trunk displacement and the center of pressure velocity improved significantly after the virtual-technological sailing program. As regards quality of life, the physical and psychosocial score significantly improved at the end of the program. A technological rehabilitation training improved balance in disabled subjects and may be used to prepare them for a real sailing course. Sailing improves the quality of life of disabled subjects and could be used in the rehabilitation.

Proposal of a Method Supporting the Interpretation of Gait Analysis Kinematic Data

Computed gait analysis is a valid tool able to assess human walking. The joint angle variation during the cycle consists in a function. The derivation process, producing angular velocity and acceleration, may reveal and quantify the small angle variations. This approach may support physician’s interpretation of the joint movements. We would like to propose a calculation, combining the data from angular velocity and angular acceleration, to obtain a graph showing some features of joint behavior. We compared the results among a healthy subject, a coxarthrosis patient and a stroke patient. The built graph clearly shows the direction changes of the joint movements and the differences between the two sides and quantifies the acceleration/deceleration of a joint. The proposed approach is a mathematical artifice, which amplifies the information contained in the usual angle graphs and possibly opens the doors to more specific rehabilitation approaches.

82. Prefrontal cortex as a compensatory functional substrate during ataxic overground gait: A correlation study between cortical activity and gait parameters

To investigate whether prefrontal cortex (PFC) activation is linked to compensatory mechanisms (time–distance parameters) or to gait features (kinematic parameters) specifically related to the functional role of the cerebellum in ataxic patients. We performed a correlation analysis between the PFC metabolic profile during gait and time–distance and kinematic parameters in a sample of 19 patients affected by neurodegenerative gait ataxia and 15 age/sex matched healthy subjects. PFC metabolism was evaluated by a 2-channel functional near-infrared imaging system while gait analysis was performed using a stereophotogrammetric system. We found a positive correlation between the PFC metabolism and the step width (the correlation coefficient was r : 0.54, p =0.02 for the right PFC, and r : 0.50, p =0.03 for the left PFC). No correlation was found between PFC activity, the other time–distance parameters and the intra-subject variability of gait. PFC activation during ataxic gait correlates with step width and therefore it seems involved in maintaining compensatory strategies rather than due to primary cerebellar deficits. To our knowledge this is the first study correlating cortical activity and gait characteristics in order to assess how cerebral cortex is modulated during a pathological gait.