Cortical Blindness, Unspecified Side of Brain, Hemianopia, Homonymous
Conditions
Keywords
multisensory, visual perception, neurorehabilitation
Brief summary
This study seeks to determine the extent of the visual capabilities that can be restored in hemianopic stroke patients by a multisensory training technique and evaluate changes in the brain that the training induces. The effectiveness of the technique will be evaluated in two interventional contexts: patients whose blindness is long-standing and stable, and another in which intervention is as soon as possible after the stroke.
Detailed description
The aims of the study are to: 1\. To identify the visual capabilities and neural circuits in stroke patients with stable hemianopia (\>6 months) that recover after regular multisensory (vs. unisensory) training sessions. This involves: 1A. Using clinical ophthalmological tests and visual perceptual tests to evaluate the visual capabilities that are recovered. 1B. Determining whether the size or extent of cortical lesions are predictive of changes induced by the training technique, and tracking changes in the residual visual circuits using functional magnetic resonance imaging (fMRI). 1C. Determining if the training-induced changes improve, persist, or degrade over time by re-assessment at a 12-month followup. 2\. Evaluate the effectiveness of an earlier (\<1 month post-stroke) and more intense training intervention strategy using the above approach and comparing the outcomes in these two approaches.
Interventions
BEHAVIORALMultisensory Training
The procedure involves repeatedly presenting identical visual-auditory stimuli at a single location in the hemianopic field (initially at 45° of eccentricity along the azimuth) while the patient maintains central fixation (0°, 0°). The visual (a 500 ms flash) and auditory (500 ms broadband noise burst) stimuli are in spatial and temporal congruence.
BEHAVIORALUnisensory Training
The procedure involves repeatedly presenting identical auditory stimuli (500 ms broadband noise burst) at a single location in the hemianopic field (initially at 45° of eccentricity along the azimuth) while the patient maintains central fixation (0°, 0°).
Sponsors
Wake Forest University Health Sciences
Study design
Allocation
RANDOMIZED
Intervention model
FACTORIAL
Primary purpose
TREATMENT
Masking
SINGLE (Outcomes Assessor)
Masking description
The experimental and control paradigms are based on sensory stimulation and there is no practical way to mask the participant from its nature, although they are not informed as to what the expected results will be. The outcomes assessor will be blinded to which stimulation arm preceded the data collection.
Intervention model description
There are two principal sub-studies: standard intervention and early intervention. Each sub-study contains a multisensory training group (experimental arm) and a unisensory training group (control arm). The unisensory training group crosses over to multisensory training at its completion. Thus, the model design is both factorial and crossover.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Age \>= 18 years old * Homonymous hemianopia diagnosed and referred by a neurologist, confirmed with Humphrey test (Goldmann size V) on first visit. Hemianopia must have been evident for at least 6 months for inclusion in the first experiment and \<1 month for inclusion in the second * Cognitively normal, defined as having normal activities of daily living OR has received a cognitive adjudication of normal through the Wake Forest University School of Medicine or equivalent within the past 12 months * MRI compatible * Has reliable transportation or is able to use transportation provided by the study * English speaking
Exclusion criteria
* Current major medical problems that might independently affect cognition, vision, or interfere with ability to attend study visits. This includes pathology of the retina or optic nerve explanatory of blindness * Unable or unwilling to attend scheduled testing and training sessions, including the 12 month follow up * Current diagnosis of a major neurological disorder that could interfere with the ability to follow task instructions (Dementia, Parkinson's disease, etc.) or that may interfere with the rehabilitation paradigm (uncorrected asymmetric hearing loss, deafness, hemineglect) * Unwilling or unable to provide consent for study participation * Current stroke symptoms deemed exclusionary by a study physician. This will be reviewed on a case-by-case basis by a study physician to determine whether factors may affect study outcomes, aims, or integrity * Taking medication that could negatively influence safety during the intervention * Enrolled in another interventional research study \<= 3 months prior to beginning this study * Self-reports regularly drinking \> 14 alcoholic beverages a week or current illicit drug use
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Functional magnetic resonance imaging (fMRI) scans | Baseline | Used to measure functional lesion and assess changes - fMRI enables the detection of abnormalities of the brain, as well as the assessment of the normal functional anatomy of the brain, which cannot be accomplished with other imaging techniques. |
| Quality of Life (QoL) Assessment | Baseline | The Veterans Affairs Low-Vision Visual Functioning Questionnaire-48 (VA-LV-VFQ-48) - A higher score on the VA LV VFQ-48 indicates better ability or less difficulty in performing activities |
| Clinical Ophthalmological Test Scores | Baseline | Humphrey tests - The Humphrey visual field test measures the entire area of peripheral vision that can be seen while the eye is focused on a central point. During this test, lights of varying intensities appear in different parts of the visual field while the patient's eye is focused on a certain spot. A normal visual field extends approximately 100° temporally (laterally), 60° nasally, 60° superiorly, and 70° inferiorly. A normal visual field measures about: 90 degrees temporally. 50 degrees superiorly and nasally. 60 degrees inferiorly |
| Visual Perception Test Scores | Baseline | Ability to detect and discriminate different visual features - The participant is asked to indicate (via button press) whether the test stimulus matches the sample (left button), does not match the sample (right button), or there was no test stimulus (withhold response). |
Countries
United States
Contacts
CONTACTBenjamin A Rowland, PhD
PRINCIPAL_INVESTIGATORBenjamin A Rowland, PhD
Wake Forest University Health Sciences
Outcome results
None listed