The present study is designed as an open label study of patients with mild cognitive impairment or dementia to evaluate longer term tolerability and potential efficacy of tyrosine kinase inhibitors. Baseline and outcome measures in this study utilize validated tests that are appropriate for repeated measures which are not affected by practice effects. Advantages of this study include the fact that the neuropsychological testing instruments and advanced MRI imaging protocols that have been in routine clinical deployment provide for a high degree of availability and reliability for diagnosis and for monitoring change of status. Quality assurance is tightly controlled. The study population is sufficiently broad and the conditions of interest are sufficiently prevalent so that recruitment of the projected numbers of subjects is not a limiting factor.