Cognitive Evaluations Provided by UC Davis Alzheimer’s Disease Research Center in Shadelands
In the February 2025 issue of The Shadelands Scene, we introduced you to the Shadelands UC Davis Alzheimer’s Disease Research Center (ADRC) and the work the researchers and clinicians do to understand, slow, and find a cure for Alzheimer’s Disease.
There is a second component to UC Davis ADRC, and that is the work of clinical neuropsychologist Johanna Rengifo, PhD, who performs neuropsychological evaluations on individuals who come to the clinic with specific cognitive concerns, helping them understand their symptoms and next steps. Dr. Rengifo is known as Dr. Johanna to staff and clients.
Johanna Rengifo, PhD, is the clinical neuropsychologist for UC Davis Alzheimer’s Disease Research Center in Shadelands, performing neuropsychological evaluations to test the brain in action and assess its abilities.
Dr. Johanna is not a part of observational research or clinical drug trials — rather, she works independent of research and solely in the field of neuropsychology, though still under the UC Davis umbrella of medical services and healthcare.
“My field is in between psychology and neurology,” said Dr. Johanna. “I help patients understand how the different areas and systems of their brain are working. There are different ways to see how the brain is working. One way is to take a picture of it — a CT scan or an MRI. But equally important is to know how the brain is actually functioning, and how the brain’s condition is affecting a person’s behavior and thinking abilities. This is done by assessing the brain in action. And that’s what I do: I test the brain in action and assess its abilities.”
A graduate of University of California, Berkeley, and Palo Alto University, Dr. Johanna has been with UC Davis ADRC in Shadelands since March 2021. In addition to her education and experience in neuropsychology, she is Spanish bilingual — an asset not often available in cognitive assessment centers. People who come to her do not have to be patients of UC Davis. Rather, her services at the Shadelands clinic are available to the entire community of Contra Costa and neighboring counties.
A cognitive assessment is a test used to measure a person’s thinking abilities, including memory, language, and reasoning skills.
People come to Dr. Johanna when they or their family members begin to notice cognitive changes in memory, thinking, and behavior. Sometimes, even slight changes trigger a visit because there is a family history of dementia and patients are wondering if they are on the path to developing dementia, as well. Others are referred by a neurologist to assess whether cognitive testing is consistent with neurological findings. According to Dr. Johanna, neuropsychological testing can be most helpful in the very early stages and during the first signs of a dementia process.
‘Through our evaluation, I’m able to help differentiate whether those changes in thinking and behavior are signs of normal aging, or if they fit a pattern that is consistent with what we know Alzheimer’s and other dementias look like,” said Dr. Johanna. “And if that’s the case, I flag it and suggest we do more evaluations. That’s when a clinical cognitive behavioral neurologist, like Dr. Chen in this UC Davis ADRC, would further evaluate with a neurological exam and additional biological markers such as blood work and/or brain imaging to see if the patterns are consistent with Alzheimer’s or other diseases that cause dementia. Not all patterns are the same; markers and patterns can be specific to specific diseases.”
Dr. Johanna spends time in her office with patients, asking questions and having them perform tasks in order to evaluate their cognitive function.
Once a person has reached out for help from Dr. Johanna, for themself or on behalf of a family member, she gathers background information on medical history and symptoms. Next, she meets with the patient alone for a three-hour cognitive testing session. These are paper/pencil tests that look at all cognitive domains of the brain, including visual and verbal memory, attention, visual spatial function, executive function, language, and processing speed.
“Because we know that different disease processes affect different parts of the brain, we look for patterns in our questioning and testing,” said Dr. Johanna, who also looks at mood and sleep — two reversible factors that can affect a person’s thinking abilities.
Cognitive evaluations don’t diagnose specific diseases; rather, they help identify issues with cognition and the need for further in-depth evaluation by a neurologist with a sub-specialty in cognitive neuroscience.
She scores the tests, writes up a report, and brings the patient and family back in to review the results and her findings, which are uploaded into the patient’s electronic medical record for their referring provider (often the primary care provider or neurologist) and other medical providers to view.
Sometimes her findings warrant a suggestion of a follow-up evaluation in 12 to 18 months. Sometimes, she suggests seeing a practicing neurologist, who would then take the next steps toward diagnosing.
She also offers lifestyle change recommendations that benefit general health and quality of life, in addition to brain health and cognitive efficiency.
“If there is cognitive decline due to a neurodegenerative disease, there’s no way to reverse it,” said Dr. Johanna. “But lifestyle changes — including getting restorative sleep, exercise, and maintaining a healthy diet — help degeneration from accelerating.”
Everything that’s good for the heart is good for the brain. “While you’re taking care of your heart,” said Dr. Johanna, “you’re taking care of your brain.”
Early detection of cognitive decline can lead to better quality of life by helping individuals and their families plan for the future, access support services, and potentially benefit from early interventions and treatments.
Doing cognitive testing early is the key. “When you first start noticing that there’s something going on, come in because I can let patients know if it’s normal aging, or if we should track them in two years, or if it’s best to see a neurologist now. Treatments that we have today are most beneficial in the earlier stages of memory loss and can help preserve a person’s memory for longer,” said Dr. Johanna.
“We still have a long way to go, and there is no cure for Alzheimer’s, but we have more options to reduce the rate of decline. Lifestyle modifications and treatments help support the journey. And we are with our patients every step.”
UC Davis Alzheimer’s Disease Research Center
100 N. Wiget Lane, Suite 150, Walnut Creek
925.357.6515