Improving Awareness for Spatial Neglect With tDCS
Trial statusNot yet recruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age20-85
SponsorUniversity of Geneva, Switzerland
About this trial
Brain-damaged patients can show severe neurological and cognitive deficits, and yet often remain strikingly unaware of these symptoms: this condition is called anosognosia. The aim of this study is to improve awareness in right-brain-damaged patients with Unilateral Spatial Neglect (USN) following stroke using transcranial direct current stimulation (tDCS). tDCS is a neuromodulatory technique that delivers low-intensity current to the brain facilitating (anodal tDCS) or inhibiting (cathodal tDCS) spontaneous neuronal activity. tDCS does not induce activity in resting neuronal networks, but modulates spontaneous neuronal activity: consequently, the amount and direction of effects critically depend on the previous state of the neural structures.
We will test USN patients showing anosognosia for neglect symptoms. Different brain areas will be stimulated, to target explicit and implicit components of anosognosia, including parietal and frontal brain regions.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
First stroke affecting the right-hemisphere
Presence of USN, as assessed by a standard neuropsychological evaluation
Structural images of the brain lesion available (magnetic resonance or tomographic scans)
Criteria for electrical brain stimulation
Disqualifiers
Presence of general cognitive deficits and/or suspicious of possible cognitive deficits
Presence of difficulty in task's comprehension
Impossibility to sustain a research session of at least 45minutes (e.g., attentional lability)
Precedent additional neurological disorder and/or current or precedent psychiatric disease
Trial design
Design model
Single group
Treatments tested in this trial
transcranial direct current stimulation (tDCS)
DeviceWe will apply tDCS to the patients' brains for 20 minutes at the intensity of 1.5mA. Each patient will undergo the three sessions (separated by at least 24h to minimize carry-over effects), in a pseudo-randomized order across patients.
Treatment groups
12 Participants
are divided into 3 treatment groupsGroup A: 1 tDCS ParietalExperimental treatment 1 intervention
Group B: 2 tDCS FrontalExperimental treatment 1 intervention
Group C: 3 ShamSham comparator 1 intervention
Trial outcomes
Primary outcomes
1
Change in self-rating about anosognosia for USN
We will use a vertical visual scale on a monitor, where the patients should evaluate their performance after each trial of a neglect task.
Time frame
from Baseline to 30 minutes2
Change in implicit measures of anosognosia for USN
Each self-rating will be time-locked with the brain activity of participants in order to record the so-called error-related potentials. Averaged evoked potentials for each domain of awareness will be computed, and a baseline correction will be applied to the epochs. The first error-related component (ERN) will be determined as the mean amplitude in the time window from 60 ms to 140 ms post-response onset; the second component of interest (Pe) will be determined as the mean amplitude in the time-window from 200 ms and 600 ms post-response onset.
Time frame
from Baseline to 30 minutesSecondary outcomes
1
Lesion correlate of recovery of anosognosia for USN
We will correlate the presence/absence of effective modulation of anosognosia for USN to the damage in specific brain regions.
Time frame
through study completion, an average of 1 yearLocations
Sponsors and contacts
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University of Geneva, Switzerland
Lead sponsor
University Hospital, Geneva
Collaborator
Source ClinicalTrials.gov
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