Anodal tDCS With Compensatory Audio-visual Training for Acquired Visual Field Defects After Brain Injury

Istituto Auxologico Italiano

Status: Completed

Conditions: Stroke; Hemianopsia, Homonymous

Treatments: Device: Anodal or sham tDCS; Behavioral: Audio-visual training

Study type: Interventional

Funder types: Other

Identifiers

NCT06116760

25C901

Details and patient eligibility

About

Homonymous visual field defects (HVFDs) following acquired brain lesions affect independent living by hampering several activities of everyday life. Available treatments are intensive and week- or month-long. Transcranial Direct current stimulation (tDCS), a plasticity-modulating non-invasive technique, could be combined with behavioral trainings to boost their efficacy or reduce treatment duration. Some promising attempts have been made pairing occipital tDCS with visual restitution training, however less is knows about which area/network should be best stimulated in association with compensatory approaches, aimed at improving exploratory abilities, such as multisensory trainings.

In the present double-blind, sham-controlled study, we assess the efficacy of a multisensory training combined with tDCS. 3 groups of participants with chronic HVFDs underwent a 10-day (1.5 hrs/day) compensatory audio-visual training combined with either real anodal tDCS applied to the ipsilesional occipital tDCS (Group 1), or the ipsilesional posterior parietal cortex (Group 2), or a sham, placebo, tDCS (Group 3).

The training require the participants to orient their gaze training spatio-temporally congruent, cross-modal, audio-visual stimuli (starting from a central fixation) and press a button as quick as possible upon the detection of the visual stimulus. All stimuli are presented on 2mx2m panel embedded with 48 LEDs and loudspeakers (Bolognini et al., 2010, Brain Research)

All participants underwent a neuropsychological assessment of visuospatial functions prior to the beginning of the training (t0), at the end of the training (t1), and at 1-month (t2) and 4-month follow-up (t3). The assessment includes: a visual detection task, three visual search tasks (EF, Triangles, and Numbers; Bolognini et al., 2005, Brain), and a questionnaire about functional impact of the HVFDs in the activities of daily living.

Enrollment: 18 patients

Sex: All

Ages: 18 to 90 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Presence of chronic (>3 months) HVFD according to Neurophtalmological evaluation, due to acquired brain injury (i.e., stroke, traumatic brain injury, brain tumor)

Exclusion criteria

• Presence of hemispatial neglect (indexed by pathological asymmetries on paper-and-pencil tests)
• Disorders of conjugated eye movements
• Other neurological disorders (e.g., dementia)
• Exclusion criteria for brain stimulation (i.e., epilepsy or family history of epilepsy; implanted electrodes, stimulators, pacemakers, infusion pumps, or any implanted metal device; pregnancy)

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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18 participants in 3 patient groups

Anodal Occipital tDCS + audio-visual training

Experimental group

Description:

Anodal tDCS on ipsilesional occipital cortex. Anode electrode placed on O1/O2 (10-20 EEG system) and reference electrode placed on the contralateral forehead. Stimulation delivered at 2mA during the first 30 minutes of the audio-visual training.

Treatment:

Behavioral: Audio-visual training

Device: Anodal or sham tDCS

Anodal Parietal tDCS + audio-visual training

Experimental group

Description:

Anodal tDCS on ipsilesional posterior parietal cortex. Anode electrode placed on P3/P4 (10-20 EEG system) and reference electrode placed on the contralateral forehead. Stimulation delivered at 2mA during the first 30 minutes of the audio-visual training.

Treatment:

Behavioral: Audio-visual training

Device: Anodal or sham tDCS

Sham tDCS + audio-visual training

Sham Comparator group

Description:

Arm 3: sham tDCS. Half of participants with Group 1 montage, the other half with Group 2 montage. Stimulator is turned off after 30s of the audio-visual training.

Treatment:

Behavioral: Audio-visual training

Device: Anodal or sham tDCS