Vestibular Stimulation to Treat Hemispatial Neglect

The purpose of the current proposal is to pilot a new and potentially improved treatment for
neglect. The procedure involves the delivery of transcutaneous small-amplitude current to the
vestibular nerves that lie directly below the mastoid bones. With the intention of boosting
activity in the damaged left hemisphere, positive and negative current is delivered to the
left and right mastoids respectively. While successfully used to rehabilitate gait and
balance disorders, the procedure has only once been applied to neglect.

In the present investigation, we will first confirm and then optimize the conditions under
which galvanic vestibular stimulation (GVS) ameliorates neglect. This in turn will justify
subsequent work (in a later funding cycle) that will demonstrate the safety and efficacy of
the treatment on a much larger clinical scale, and merit the construction of a miniaturized
portable device.

Inclusion Criteria:

- All participants must be literate in English

- Right handed

- Have corrected near-visual acuity of 20/40 or better

- Patients must also have a minimum of twelve years education

- These inclusionary criteria are based on the data of both Black, Yu, Martin, and
Szalai (90) and our own studies.

- They are intended to assure that only patients with sufficiently severe symptoms
will be admitted to our study.

Exclusion Criteria:

Exclusionary criteria include:

- Homonymous hemianopia

- Presence of a severe field cut extending toward the midline on formal perimetry
(however many patients who have field cuts restricted to the periphery will be able to
fully perceive our stimulus displays so can be included

- Evidence of aphasia on clinical examination (crossed aphasia)

- A significant history of other neurological or psychiatric illness or drug/alcohol
abuse