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Adriana Bastos Conforto - One of the best experts on this subject based on the ideXlab platform.

  • Effects of Somatosensory Stimulation on corticomotor excitability in patients with unilateral cerebellar infarcts and healthy subjects - preliminary results
    Cerebellum & Ataxias, 2014
    Co-Authors: Suzete Nascimento Farias Da Guarda, Adriana Bastos Conforto
    Abstract:

    In healthy humans, Somatosensory Stimulation in the form of 2 h-repetitive peripheral afferent nerve Stimulation (SS) increases excitability of the contralateral motor cortex. In this preliminary study, we explored effects of SS on excitability to transcranial magnetic Stimulation (TMS) in patients with unilateral cerebellar infarcts and age-matched controls. Ten patients with infarcts in one cerebellar hemisphere and six age-matched controls participated in the study. Each subject participated in one session of active, and one session of sham SS delivered to the median nerve ipsilateral to the cerebellar infarct in patients, and to the homologous nerve in controls. Before and after each session, the following TMS measures were performed: resting motor threshold (rMT), motor evoked potentials (MEPs), short-interval intracortical inhibition (SICI) and short-interval intracortical facilitation (SICF). Amplitudes of motor evoked potentials were normalized to amplitudes of supramaximal M responses (MEP/M ratios). In the control group, there was a significant increase in rMT, and a significant increase in MEP/M ratios after active, but not after sham SS. There were no significant differences in rMT or MEP/M ratios in the group of patients after active or sham SS. There were no significant differences in SICI or SICF after active or sham SS in either group. Consistent with results reported in rodents, these preliminary findings suggest for the first time in humans, that normal cerebellar activity is required so that SS can modulate excitability of the sensorimotor cortex.

  • Effects of Somatosensory Stimulation on corticomotor excitability in patients with unilateral cerebellar infarcts and healthy subjects - preliminary results
    Cerebellum & Ataxias, 2014
    Co-Authors: Suzete Nascimento Farias Da Guarda, Adriana Bastos Conforto
    Abstract:

    Background In healthy humans, Somatosensory Stimulation in the form of 2 h-repetitive peripheral afferent nerve Stimulation (SS) increases excitability of the contralateral motor cortex. In this preliminary study, we explored effects of SS on excitability to transcranial magnetic Stimulation (TMS) in patients with unilateral cerebellar infarcts and age-matched controls. Methods Ten patients with infarcts in one cerebellar hemisphere and six age-matched controls participated in the study. Each subject participated in one session of active, and one session of sham SS delivered to the median nerve ipsilateral to the cerebellar infarct in patients, and to the homologous nerve in controls. Before and after each session, the following TMS measures were performed: resting motor threshold (rMT), motor evoked potentials (MEPs), short-interval intracortical inhibition (SICI) and short-interval intracortical facilitation (SICF). Amplitudes of motor evoked potentials were normalized to amplitudes of supramaximal M responses (MEP/M ratios). Results In the control group, there was a significant increase in rMT, and a significant increase in MEP/M ratios after active, but not after sham SS. There were no significant differences in rMT or MEP/M ratios in the group of patients after active or sham SS. There were no significant differences in SICI or SICF after active or sham SS in either group. Conclusion Consistent with results reported in rodents, these preliminary findings suggest for the first time in humans, that normal cerebellar activity is required so that SS can modulate excitability of the sensorimotor cortex.

  • Effects of Somatosensory Stimulation on the excitability of the unaffected hemisphere in chronic stroke patients.
    Clinics, 2008
    Co-Authors: Adriana Bastos Conforto, Renata Laurenti Dos Santos, Suely Kazue Nagahashi Marie, Suzete Nascimento Farias, Nadia Nader Mangini, Leonardo G. Cohen
    Abstract:

    INTRODUCTION: Somatosensory Stimulation of the paretic upper limb enhances motor performance and excitability in the affected hemisphere, and increases activity in the unaffected hemisphere, in chronic stroke patients. We tested the hypothesis that Somatosensory Stimulation of the paretic hand would lead to changes in excitability of the unaffected hemisphere in these patients, and we investigated the relation between motor function of the paretic hand and excitability of the unaffected hemisphere. METHODS: Transcranial magnetic Stimulation was administered to the unaffected hemisphere of nine chronic stroke patients. Patients were submitted to 2-h Somatosensory Stimulation in the form of median nerve Stimulation and control Stimulation using a cross-over design. Baseline Jebsen-Taylor test scores were evaluated. Resting motor threshold, intracortical facilitation, short-interval intracortical inhibition, and visual analog scores for attention, fatigue and drowsiness were measured across conditions. RESULTS: Better pre-Stimulation baseline motor function was correlated with deeper SICI in the unaffected hemisphere. We found no overt changes in any physiological marker after Somatosensory Stimulation. There was increased drowsiness in the control session, which may have led to changes in intracortical facilitation. CONCLUSIONS: Our results do not support an overt effect of a single session of Somatosensory Stimulation of the paretic hand on motor cortical excitability of the unaffected hemisphere as measured by motor threshold, short-interval intracortical inhibition or intracortical facilitation. It remains to be determined if other markers of cortical excitability are modulated by Somatosensory Stimulation, and whether repeated sessions or lesion location may lead to different effects.

  • Effects of Somatosensory Stimulation on motor function in chronic cortico-subcortical strokes.
    Journal of Neurology, 2007
    Co-Authors: Adriana Bastos Conforto, Leonardo G. Cohen, Renata Laurenti Dos Santos, Milberto Scaff, Suely Kazue Nagahashi Marie
    Abstract:

    Somatosensory Stimulation enhances aspects of motor function in patients with chronic, predominantly subcortical infarcts. We investigated the effects of Somatosensory Stimulation on motor function in stroke patients with predominantly cortical involvement in the middle cerebral artery territory in a double-blind, pseudorandomized crossover trial. Motor performance was evaluated with the Jebsen-Taylor test before, after 2-hour Somatosensory Stimulation, and after subsequent motor training (n = 11). In one experimental session, patients were submitted to median nerve Stimulation (MNS) and in the other session, to control Stimulation (CS). The order of the sessions was counterbalanced across patients. Improvement in performance in the Jebsen-Taylor test after Somatosensory Stimulation and after motor training was significantly greater in the MNS session than in the CS session. Additionally, patients who received MNS in the second session maintained the beneficial effects of training 30 days later. A single MNS session improves hand motor function in patients with chronic cortico-subcortical strokes and appears to favor consolidation of training effects. Somatosensory Stimulation may be an adjuvant tool for stroke rehabilitation in patients with cortical lesions.

  • Increase in hand muscle strength of stroke patients after Somatosensory Stimulation.
    Annals of Neurology, 2002
    Co-Authors: Adriana Bastos Conforto, Alain Kaelin-lang, Leonardo G. Cohen
    Abstract:

    It has been proposed that Somatosensory input in the form of peripheral nerve Stimulation can influence functional measures of motor performance. We studied the effects of median nerve Stimulation on pinch muscle strength (a function mediated predominantly by median nerve innervated muscles) in the affected hand of chronic stroke patients. A 2-hour period of median nerve Stimulation elicited an increase in pinch strength that outlasted the Stimulation period. The improvement in muscle strength correlated with stimulus intensity and was identified in the absence of motor training. These results suggest that Somatosensory Stimulation may be a promising adjuvant to rehabilitation of the motor deficits in stroke patients.

Leonardo G. Cohen - One of the best experts on this subject based on the ideXlab platform.

  • Effects of Somatosensory Stimulation on the excitability of the unaffected hemisphere in chronic stroke patients.
    Clinics, 2008
    Co-Authors: Adriana Bastos Conforto, Renata Laurenti Dos Santos, Suely Kazue Nagahashi Marie, Suzete Nascimento Farias, Nadia Nader Mangini, Leonardo G. Cohen
    Abstract:

    INTRODUCTION: Somatosensory Stimulation of the paretic upper limb enhances motor performance and excitability in the affected hemisphere, and increases activity in the unaffected hemisphere, in chronic stroke patients. We tested the hypothesis that Somatosensory Stimulation of the paretic hand would lead to changes in excitability of the unaffected hemisphere in these patients, and we investigated the relation between motor function of the paretic hand and excitability of the unaffected hemisphere. METHODS: Transcranial magnetic Stimulation was administered to the unaffected hemisphere of nine chronic stroke patients. Patients were submitted to 2-h Somatosensory Stimulation in the form of median nerve Stimulation and control Stimulation using a cross-over design. Baseline Jebsen-Taylor test scores were evaluated. Resting motor threshold, intracortical facilitation, short-interval intracortical inhibition, and visual analog scores for attention, fatigue and drowsiness were measured across conditions. RESULTS: Better pre-Stimulation baseline motor function was correlated with deeper SICI in the unaffected hemisphere. We found no overt changes in any physiological marker after Somatosensory Stimulation. There was increased drowsiness in the control session, which may have led to changes in intracortical facilitation. CONCLUSIONS: Our results do not support an overt effect of a single session of Somatosensory Stimulation of the paretic hand on motor cortical excitability of the unaffected hemisphere as measured by motor threshold, short-interval intracortical inhibition or intracortical facilitation. It remains to be determined if other markers of cortical excitability are modulated by Somatosensory Stimulation, and whether repeated sessions or lesion location may lead to different effects.

  • Effects of Somatosensory Stimulation on motor function in chronic cortico-subcortical strokes.
    Journal of Neurology, 2007
    Co-Authors: Adriana Bastos Conforto, Leonardo G. Cohen, Renata Laurenti Dos Santos, Milberto Scaff, Suely Kazue Nagahashi Marie
    Abstract:

    Somatosensory Stimulation enhances aspects of motor function in patients with chronic, predominantly subcortical infarcts. We investigated the effects of Somatosensory Stimulation on motor function in stroke patients with predominantly cortical involvement in the middle cerebral artery territory in a double-blind, pseudorandomized crossover trial. Motor performance was evaluated with the Jebsen-Taylor test before, after 2-hour Somatosensory Stimulation, and after subsequent motor training (n = 11). In one experimental session, patients were submitted to median nerve Stimulation (MNS) and in the other session, to control Stimulation (CS). The order of the sessions was counterbalanced across patients. Improvement in performance in the Jebsen-Taylor test after Somatosensory Stimulation and after motor training was significantly greater in the MNS session than in the CS session. Additionally, patients who received MNS in the second session maintained the beneficial effects of training 30 days later. A single MNS session improves hand motor function in patients with chronic cortico-subcortical strokes and appears to favor consolidation of training effects. Somatosensory Stimulation may be an adjuvant tool for stroke rehabilitation in patients with cortical lesions.

  • Somatosensory Stimulation enhances the effects of training functional hand tasks in patients with chronic stroke
    Archives of Physical Medicine and Rehabilitation, 2007
    Co-Authors: Pablo A Celnik, Friedhelm C. Hummel, Michelle L. Harris-love, Rebecca Wolk, Leonardo G. Cohen
    Abstract:

    Celnik P, Hummel F, Harris-Love M, Wolk R, Cohen LG. Somatosensory Stimulation enhances the effects of training functional hand tasks in patients with chronic stroke. Arch Phys Med Rehabil 2007;88:1369-76. Objective: To test the hypothesis that Somatosensory stim- ulation would enhance the effects of training functional hand tasks immediately after practice and 1 day later in chronic subcortical stroke patients. Design: Single-blinded and randomized, crossover study. Setting: Human research laboratory. Participants: Nine chronic subcortical stroke patients. Interventions: Three separate sessions of motor training preceded by (1) synchronous peripheral nerve Stimulation (PNS), (2) no Stimulation, or (3) asynchronous PNS. Main Outcome Measures: Time to complete the Jebsen- Taylor Hand Function Test (JTHFT time) and corticomotor excitability tested with transcranial magnetic Stimulation. Results: After familiarization practice, during which all patients reached a performance plateau, training under the effects of PNS reduced JTHFT time by 10% beyond the post- familiarization plateau. This behavioral gain was accompanied by a specific reduction in GABAergically mediated intracorti- cal inhibition in the motor cortex. These findings were not observed after similar practice under the influence of no stim- ulation or asynchronous PNS sessions. Conclusions: Somatosensory Stimulation may enhance the training of functional hand tasks in patients with chronic stroke, possibly through modulation of intracortical GABAergic pathways.

  • Influence of Electric Somatosensory Stimulation on Paretic-Hand Function in Chronic Stroke
    Archives of Physical Medicine and Rehabilitation, 2006
    Co-Authors: Hyae-jung Seo, Leonardo G. Cohen
    Abstract:

    Abstract Wu CW, Seo H-J, Cohen LG. Influence of electric Somatosensory Stimulation on paretic-hand function in chronic stroke. Objective To test the influence of electric Somatosensory Stimulation on performance of the Jebsen-Taylor Hand Function Test (JTHFT), a widely used assessment of functional hand motor skills, by the paretic arm in patients with chronic stroke. Design Initially, patients trained for several sessions until reaching plateau performance on the JTHFT. Subsequently, they entered a crossover randomized study, designed to evaluate the influence of Somatosensory Stimulation on JTHFT performance. Setting A research laboratory. Participants Nine patients with chronic stroke (≥1.5y) who acutely had marked weakness (paralysis of the upper extremity is evaluated as equal or below Medical Research Council [MRC] grade 2) followed by improvement to an MRC grade of 4.24±0.43 (range, 3.5–4.9) and Fugl-Meyer Assessment (FMA) score of 86.43%±2.02% at the time of testing. Interventions Two hours of electric Somatosensory Stimulation was applied to the (1) paretic hand, (2) paretic leg, or (3) no Stimulation in different sessions, in a randomized order. Main Outcome Measure The time required to complete the JTHFT was analyzed by using repeated-measures analysis of variance (ANOVA) with factors time (pre-, postintervention) and intervention (paretic hand, paretic leg, no Stimulation) followed by post hoc testing. Results Significant effects of intervention and intervention by time interaction ( P P Conclusions Somatosensory Stimulation applied to a paretic limb can benefit performance of a functional test in patients with chronic stroke. This result supports the proposal that electric sensory Stimulation in combination with training protocols may enhance the benefit of customary neurorehabilitative treatments and possibly motor learning.

  • Enduring representational plasticity after Somatosensory Stimulation
    NeuroImage, 2005
    Co-Authors: Peter Van Gelderen, Takashi Hanakawa, Zaneb Yaseen, Leonardo G. Cohen
    Abstract:

    Somatosensory Stimulation (SS), leading to increases in motor cortical excitability, influences motor performance in patients with brain lesions like stroke. The mechanisms by which SS modulates motor function are incompletely understood. Here, we used functional magnetic resonance imaging (fMRI, blood-oxygenation-level-dependent (BOLD), and perfusion imagings simultaneously acquired in a 3 T magnet) to assess the effects of SS on thumb-movement-related activation in three regions of interest (ROI) in the motor network: primary motor cortex (M1), primary Somatosensory cortex (S1), and dorsal premotor cortex (PMd) in healthy volunteers. Scans were obtained in different sessions before and after 2-h electrical Stimulation applied to the median nerve at the wrist (MNS), to the skin overlying the shoulder deltoid muscle (DMS), and in the absence of Stimulation (NOSTIM) in a counterbalanced design. We found that baseline perfusion intensity was comparable within and across sessions. MNS but not DMS nor NOSTIM led to an increase in signal intensity and number of voxels activated by performance of median nerve-innervated thumb movements in M1, S1, and PMd for up to 60 min. Task-related fMRI activation changes were most prominent in M1 followed by S1 and to a lesser extent in PMd. MNS elicited a displacement of the center of gravity for the thumb movement representation towards the other finger representations within S1. These results indicate that MNS leads to an expansion of the thumb representation towards other finger representations within S1, a form of plasticity that may underlie the influence of SS on motor cortical function, possibly supporting beneficial effects on motor control.

Suzete Nascimento Farias Da Guarda - One of the best experts on this subject based on the ideXlab platform.

  • Effects of Somatosensory Stimulation on corticomotor excitability in patients with unilateral cerebellar infarcts and healthy subjects - preliminary results
    Cerebellum & Ataxias, 2014
    Co-Authors: Suzete Nascimento Farias Da Guarda, Adriana Bastos Conforto
    Abstract:

    In healthy humans, Somatosensory Stimulation in the form of 2 h-repetitive peripheral afferent nerve Stimulation (SS) increases excitability of the contralateral motor cortex. In this preliminary study, we explored effects of SS on excitability to transcranial magnetic Stimulation (TMS) in patients with unilateral cerebellar infarcts and age-matched controls. Ten patients with infarcts in one cerebellar hemisphere and six age-matched controls participated in the study. Each subject participated in one session of active, and one session of sham SS delivered to the median nerve ipsilateral to the cerebellar infarct in patients, and to the homologous nerve in controls. Before and after each session, the following TMS measures were performed: resting motor threshold (rMT), motor evoked potentials (MEPs), short-interval intracortical inhibition (SICI) and short-interval intracortical facilitation (SICF). Amplitudes of motor evoked potentials were normalized to amplitudes of supramaximal M responses (MEP/M ratios). In the control group, there was a significant increase in rMT, and a significant increase in MEP/M ratios after active, but not after sham SS. There were no significant differences in rMT or MEP/M ratios in the group of patients after active or sham SS. There were no significant differences in SICI or SICF after active or sham SS in either group. Consistent with results reported in rodents, these preliminary findings suggest for the first time in humans, that normal cerebellar activity is required so that SS can modulate excitability of the sensorimotor cortex.

Suzete Nascimento Farias Da Guarda - One of the best experts on this subject based on the ideXlab platform.

  • Effects of Somatosensory Stimulation on corticomotor excitability in patients with unilateral cerebellar infarcts and healthy subjects - preliminary results
    Cerebellum & Ataxias, 2014
    Co-Authors: Suzete Nascimento Farias Da Guarda, Adriana Bastos Conforto
    Abstract:

    Background In healthy humans, Somatosensory Stimulation in the form of 2 h-repetitive peripheral afferent nerve Stimulation (SS) increases excitability of the contralateral motor cortex. In this preliminary study, we explored effects of SS on excitability to transcranial magnetic Stimulation (TMS) in patients with unilateral cerebellar infarcts and age-matched controls. Methods Ten patients with infarcts in one cerebellar hemisphere and six age-matched controls participated in the study. Each subject participated in one session of active, and one session of sham SS delivered to the median nerve ipsilateral to the cerebellar infarct in patients, and to the homologous nerve in controls. Before and after each session, the following TMS measures were performed: resting motor threshold (rMT), motor evoked potentials (MEPs), short-interval intracortical inhibition (SICI) and short-interval intracortical facilitation (SICF). Amplitudes of motor evoked potentials were normalized to amplitudes of supramaximal M responses (MEP/M ratios). Results In the control group, there was a significant increase in rMT, and a significant increase in MEP/M ratios after active, but not after sham SS. There were no significant differences in rMT or MEP/M ratios in the group of patients after active or sham SS. There were no significant differences in SICI or SICF after active or sham SS in either group. Conclusion Consistent with results reported in rodents, these preliminary findings suggest for the first time in humans, that normal cerebellar activity is required so that SS can modulate excitability of the sensorimotor cortex.

Edelle C. Field-fote - One of the best experts on this subject based on the ideXlab platform.