The primary purpose of this study is to assess whether hyperbaric oxygen treatment improves neurological function in patients who exhibit white matter hyperintensities on MRI examination.

The secondary goal of this study is to determine if it is possible using MRI to discern a difference in perfusion of central nervous system tissue in regions of white matter hyperintensities after hyperbaric oxygen administration as compared to hyperbaric air.

Consecutively enrolled patients will be assigned to hyperbaric oxygen or hyperbaric air by random number. Physicians supervising the hyperbaric treatments and the treating technicians, the evaluating neurologist, and the interpreter of the MRIs will be blinded regarding patient treatment status. All patients who receive placebo will be offered treatment with hyperbaric oxygen.

Inclusion Criteria:

• Over 50 years of age
• White Matter Hyperintensities on MRI of brain
• Two or more symptoms and/or Neurological impairments e.g. gait disturbance, dysequilibrium, decline in cognitive function, upper motor neuron deficit, dysmetria, hyper-reflex or unilateral increase in muscle tone

Exclusion Criteria:

• Contraindications to hyperbaric oxygen therapy e.g. pulmonary emphysema or bullae, claustrophobia, seizure disorder
• Inability of the patient to tolerate pressurization e.g. eustachian tube dysfunction
• Extreme cognitive impairment
• Major Depression
• Other uncontrolled co-morbidities e.g. diabetes, hypertension, thyroid disorders, carotid artery stenosis (over 70%), renal or hepatic dysfunction
• History of brain tumor, head trauma, electroshock therapy,brain irradiation or migraine headaches

Patients with neurological Symptom or deficits who demonstrate evidence of small vessel disease of the brain by leukoencephalopathy