Hand disability after stroke has a profound negative impact on functional ability and independence. Hand therapy may be augmented with sensory stimulation for better outcomes. We have developed a novel sensory stimulation - unfelt vibration applied via a wristwatch. Participants will receive this novel stimulation with hand task practice therapy or therapy only to determine if use of this stimulation is better for recovery.

The purpose of the study is to generate a bio bank of specimens for research. We will tissue that would otherwise be discarded from clinical or surgical procedure and information from medical records. We will also collect discarded blood, urines and sputum. Collecting samples will help to better understanding the mechanisms of cardiovascular diseases, identify biomarkers for early diagnosis and to predict safety and efficacy of new therapies.

The purpose of this study is to use neuroimaging to understand how networks in the brain change over time. Although the single most significant risk factor for developing Alzheimer's disease (AD) is age, the neurobiological processes underlying the transition from normal aging to AD are not well understood. Our group of researchers has developed ways to use MRI to detect small changes in certain parts of the brain. We will use neuroimaging to understand how the connections in the brain change over time in healthy aging. The goal is to discover which brain changes are present in healthy aging.

Participants will have two study visits (about 2 years apart) where they will undergo tests to assess mental function, fill out questionnaires, and undergo a blood draw, brain MRI and PET scan and provide a saliva sample. At the second visit, participants will not repeat PET scan. Participants will continue to be followed longitudinally every two years as long as the study is funded.

Participants are required to have a Co-Participant accompany them for the first portion of each visit. This individual must be a reliable informant that has contact with the participant at least once per week.

Older adults typically have trouble identifying the speech they hear, especially in noisy environments. Fortunately, compared to younger adults, older adults are better able to compensate for difficulties identifying the speech they hear by recruiting the visual system. However, the extent to which older adults can benefit from visual input, and how this influence relates to age-related changes in brain structure and function, have not been thoroughly investigated. The general purpose of this study is to determine how age-related changes in brain structure and function affect how well people hear and see. This study seeks participants with normal hearing to mild hearing loss, who also have normal or corrected-to-normal vision.

With this research study, we want to learn if methylphenidate (Ritalin® and others) helps people with Alzheimer's disease and apathy (lack of interest or concern for things that others find moving or exciting).