Time filter

Source Type

Velazquez-Perez L.,Centro Para La Investigacion Y Rehabilitacion Of Las Ataxias Hereditarias | Rodriguez-Labrada R.,Centro Para La Investigacion Y Rehabilitacion Of Las Ataxias Hereditarias | Canales-Ochoa N.,Centro Para La Investigacion Y Rehabilitacion Of Las Ataxias Hereditarias | Sanchez-Cruz G.,Centro Para La Investigacion Y Rehabilitacion Of Las Ataxias Hereditarias | And 7 more authors.
Journal of the Neurological Sciences | Year: 2010

Nerve conduction is profoundly affected in Spinocerebellar ataxia 2 (SCA2) even before the onset of the disease, but there is no information regarding its progression to the final stage of SCA2. In order to study the progression patterns of nerve conduction abnormalities in SCA2 we performed a prospective follow up evaluation of sensory and motor conduction in 21 SCA2 mutation carriers-initially presymptomatics- and 19 non-SCA2 mutation carriers during 20 years. The earliest electrophysiological alterations were the reduction of sensory amplitudes in median and sural nerves, which could be found 8 to 5 years prior disease onset and in the last 4 years of the preclinical stage respectively. These abnormalities were followed by the increase of sensory latencies and decrease of conduction velocities. Sensory amplitudes progressively decreased during the follow-up clinical stage, rendering almost all patients with abnormal amplitudes and lack of sensory potentials, with faster progression rates in patients with larger CAG repeat lengths. Peripheral motor nerves showed the later involvement. These findings were used to define three distinct stages that describe the progression of the peripheral neuropathy. We suggest that sensory amplitudes could be useful biomarkers to assess the progression of peripheral nerve involvement and therefore to evaluate future clinical trials of therapeutic agents. © 2009 Elsevier B.V. All rights reserved.


Russell C.,Brunel University | Russell C.,Laboratorio Of Neuropsicologia | Deidda C.,Laboratorio Of Neuropsicologia | Malhotra P.,Imperial College London | And 4 more authors.
Brain | Year: 2010

Constructional apraxia refers to the inability of patients to copy accurately drawings or three-dimensional constructions. It is a common disorder after right parietal stroke, often persisting after initial problems such as visuospatial neglect have resolved. However, there has been very little experimental investigation regarding mechanisms that might contribute to the syndrome. Here, we examined whether a key deficit might be failure to integrate visual information correctly from one fixation to the next. Specifically, we tested whether this deficit might concern remapping of spatial locations across saccades. Right-hemisphere stroke patients with constructional apraxia were compared to patients without constructional problems and neurologically healthy controls. Participants judged whether a pattern shifted position (spatial task) or changed in pattern (non-spatial task) across two saccades, compared to a control condition with an equivalent delay but without intervening eye movements. Patients with constructional apraxia were found to be significantly impaired in position judgements with intervening saccades, particularly when the first saccade of the sequence was to the right. The importance of these remapping deficits in constructional apraxia was confirmed through a highly significant correlation between saccade task performance and constructional impairment on standard neuropsychological tasks. A second study revealed that even single saccades to the right can impair constructional apraxia patients' perception of location shifts. These data are consistent with the view that rightward eye movements result in loss of remembered spatial information from previous fixations, presumably due to constructional apraxia patients' damage to the right-hemisphere regions involved in remapping locations across saccades. These findings provide the first evidence for a deficit in remapping visual information across saccades underlying right-hemisphere constructional apraxia.


Broetz D.,University of Tübingen | Braun C.,University of Tübingen | Braun C.,University of Trento | Weber C.,Laboratorio Of Neuropsicologia | And 4 more authors.
Neurorehabilitation and Neural Repair | Year: 2010

Background. There is no accepted and efficient rehabilitation strategy to reduce focal impairments for patients with chronic stroke who lack residual movements. Methods. A 67-year-old hemiplegic patient with no active finger extension was trained with a brainĝ"computer interface (BCI) combined with a specific daily lifeĝ"oriented physiotherapy. The BCI used electrical brain activity (EEG) and magnetic brain activity (MEG) to drive an orthosis and a robot affixed to the patientĝs affected upper extremity, which enabled him to move the paralyzed arm and hand driven by voluntary modulation of 1/4-rhythm activity. In addition, the patient practiced goal-directed physiotherapy training. Over 1 year, he completed 3 training blocks. Arm motor function, gait capacities (using Fugl-Meyer Assessment, Wolf Motor Function Test, Modified Ashworth Scale, 10-m walk speed, and goal attainment score), and brain reorganization (functional MRI, MEG) were repeatedly assessed. Results. The ability of hand and arm movements as well as speed and safety of gait improved significantly (mean 46.6%). Improvement of motor function was associated with increased 1/4-oscillations in the ipsilesional motor cortex. Conclusion. This proof-of-principle study suggests that the combination of BCI training with goal-directed, active physical therapy may improve the motor abilities of chronic stroke patients despite apparent initial paralysis. © The Author(s) 2010.


Russell C.,Brunel University | Russell C.,Laboratorio Of Neuropsicologia | Malhotra P.,Imperial College London | Deidda C.,Laboratorio Of Neuropsicologia | And 2 more authors.
Cortex | Year: 2013

Introduction: Attention modulates the availability of sensory information to conscious perception. In particular, there is evidence of pathological, spatial constriction of the effective field of vision in patients with right hemisphere damage when a central task exhausts available attentional capacity. In the current study we first examined whether this constriction might be modulated across both space and time in right hemisphere stroke patients without neglect. Then we tested healthy elderly people to determine whether non-pathological ageing also leads to spatiotemporal impairments of vision under conditions of high attention load. Methods: Right hemisphere stroke patients completed a task at fixation while attempting to discriminate letters appearing in the periphery. Attentional load of the central task was modulated by increasing task difficulty. Peripheral letters appeared simultaneously with the central task or at different times (stimulus onset asynchronies, SOAs) after it. In a second study healthy elderly volunteers were tested with a modified version of this paradigm. Results: Under conditions of high attention load right hemisphere stroke patients have a reduced effective visual field, over a significantly extended 'attentional blink', worse for items presented to their left. In the second study, older participants were unable to discriminate otherwise salient items across the visual field (left or right) when their attention capacity was loaded on the central task. This deficit extended temporally, with peripheral discrimination ability not returning to normal for up to 450msec. Conclusions: Dynamically tying up attention resources on a task at fixation can have profound effects in patient populations and in normal ageing. These results demonstrate that items can escape conscious detection across space and time, and can thereby impact significantly on visual perception in these groups. © 2012 Elsevier Ltd.


Semenza C.,University of Padua | Semenza C.,Laboratorio Of Neuropsicologia | Meneghello F.,Laboratorio Of Neuropsicologia | Arcara G.,Laboratorio Of Neuropsicologia | And 7 more authors.
Frontiers in Aging Neuroscience | Year: 2014

The aim of this study was to build an instrument, the numerical activities of daily living (NADL), designed to identify the specific impairments in numerical functions that may cause problems in everyday life. These impairments go beyond what can be inferred from the available scales evaluating activities of daily living in general, and are not adequately captured by measures of the general deterioration of cognitive functions as assessed by standard clinical instruments like the MMSE and MoCA. We assessed a control group (n = 148) and a patient group affected by a wide variety of neurological conditions (n = 175), with NADL along with IADL, MMSE, and MoCA. The NADL battery was found to have satisfactory construct validity and reliability, across a wide age range. This enabled us to calculate appropriate criteria for impairment that took into account age and education. It was found that neurological patients tended to overestimate their abilities as compared to the judgment made by their caregivers, assessed with objective tests of numerical abilities. © 2014 Semenza, Meneghello, Arcara, Burgio, Gnoato, Facchini, Benavides-Varela, Clementi and Butterworth.


PubMed | Laboratorio Of Neuropsicologia, University of Padua and University College London
Type: | Journal: Frontiers in aging neuroscience | Year: 2014

The aim of this study was to build an instrument, the numerical activities of daily living (NADL), designed to identify the specific impairments in numerical functions that may cause problems in everyday life. These impairments go beyond what can be inferred from the available scales evaluating activities of daily living in general, and are not adequately captured by measures of the general deterioration of cognitive functions as assessed by standard clinical instruments like the MMSE and MoCA. We assessed a control group (n = 148) and a patient group affected by a wide variety of neurological conditions (n = 175), with NADL along with IADL, MMSE, and MoCA. The NADL battery was found to have satisfactory construct validity and reliability, across a wide age range. This enabled us to calculate appropriate criteria for impairment that took into account age and education. It was found that neurological patients tended to overestimate their abilities as compared to the judgment made by their caregivers, assessed with objective tests of numerical abilities.

Loading Laboratorio Of Neuropsicologia collaborators
Loading Laboratorio Of Neuropsicologia collaborators