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NCT Number: NCT06116760

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

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.

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Key information

Conditions

Stroke Blindness Brain Diseases Cardiovascular Diseases Central Nervous System Diseases Cerebrovascular Disorders Eye Diseases Hemianopsia Hemianopsia, Homonymous Nervous System Diseases Neurologic Manifestations Pathological Conditions, Signs and Symptoms Sensation Disorders Signs and Symptoms Vascular Diseases Vision Disorders

Age range

18 year–90 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Istituto Auxologico Italiano IRCCS

Milan, Lombardy, 20122, Italy

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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)

Treatment and study plan

Anodal or sham tDCS

Device

Anodal or sham tDCS (see "Arms") is applied during the execution of an audio-visual training.

Audio-visual training

Behavioral

90 min/day x 10 days. Participants are seated in front of a 2 m × 2 m training board, at a distance of 1.2 m, in a dimly lit room. The board features 48 red light-emitting diodes (LED, diameter 1 cm, luminance 90 cd m2), distributed in six horizontal rows (eight lights per row). Forty-eight piezoelectric loudspeakers (0.4 W, 8Ω) are located above each light, producing a white-noise (80 dB, duration 100 ms).

Spatio-temporally congruent, cross-modal, audio-visual stimuli are presented at one out of 48 possible positions on the board. Participants are instructed to look at the fixation point - at the center of the apparatus - and to move their eyes to detect the presence of the visual stimulus (duration=100 ms) by pressing right button of a wireless mouse.

Primary outcomes

  1. Change from baseline in Accuracy on the EF Task

    Time frame: At baseline (at the beginning of the treatment), at the end of the treatment, at 1- and 4-month follow-ups

    Computerized visual search task. Participants have to search for the target letter "F" surrounded by distractors "E"s. Accuracy: the proportion of correct responses (range 0-1).

  2. Change from baseline in Response Times (RTs) on the EF Task

    Time frame: At baseline (at the beginning of the treatment), at the end of the treatment, at 1- and 4-month follow-ups

    Computerized visual search task. Participants have to search for the target letter "F" surrounded by distractors "E"s. RTs: median search times (seconds) of correct responses.

  3. Change from baseline in Accuracy on the Triangle Task

    Time frame: At baseline (at the beginning of the treatment), at the end of the treatment, at 1- and 4-month follow-ups

    Computerized visual search task. Participants have to report the number of triangles (targets) surrounded by square distractors. Accuracy: the proportion of correct responses (range 0-1).

  4. Change from baseline in RTs on the Triangle Task

    Time frame: At baseline (at the beginning of the treatment), at the end of the treatment, at 1- and 4-month follow-ups

    Computerized visual search task. Participants have to report the number of triangles (targets) surrounded by square distractors. RTs: median search times (seconds) of correct responses.

  5. Change from baseline in RTs on the Numbers Task

    Time frame: At baseline (at the beginning of the treatment), at the end of the treatment, at 1- and 4-month follow-ups

    Computerized visual search task. Participants have to point to numbers (1 to 15) in ascending order. RTs: median search times (seconds).

  6. Change from baseline in the functional scale assessing the impact of vision loss in everyday life activities

    Time frame: At baseline (at the beginning of the treatment), at the end of the treatment, at 1- and 4-month follow-ups

    A scale assessing the impact of HVFDs on nine activities of daily living. For each item, the score ranges from 0 ("No difficulty") to 4 ("Very frequent difficulties").

Secondary outcomes

  1. Change from baseline in Accuracy on the Visual Detection Task

    Time frame: At baseline (at the beginning of the treatment), at the end of the treatment, at 1- and 4-month follow-ups

    Detection of visual stimuli presented on the same panel employed for the training. Accuracy (the proportion of detected stimuli; range 0-1) is calculated for both the sighted and the blind hemifields.

  2. Change from baseline in RTs on the Visual Detection Task

    Time frame: At baseline (at the beginning of the treatment), at the end of the treatment, at 1- and 4-month follow-ups

    Detection of visual stimuli presented on the same panel employed for the training. RTs: median search times of the detected stimuli are calculated for both the sighted and the blind hemifields.

Sponsors and collaborators

Lead sponsor

Istituto Auxologico Italiano

Other

Registry information

Important dates

Study start
2016
Primary completion
2023
Study completion
2023
First posted
Nov 3, 2023
Registry last updated
Mar 12, 2024

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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