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Dementia: Basis in Neurology

medical personnel holding a brain scan

Do you need a neurologist on your dementia care team? The science of dementia says yes. Today, we face an “explosion of geriatric-onset, debilitating brain disease,” says Steven Posar, MD, CEO & Founder of GuideStar Eldercare—disease that we usually call dementia. “There are many causes, and there are many clinical presentations,” he adds.

Multiple pathologies in dementia

A focus on neuropathology is foundational to understanding dementia illnesses, according to the NIH. Currently engaged in intensive research about the neuropathology of dementia, the NIH says dementia reflects multiple neuropathologies that affect brain functioning. Researchers are striving to identify underlying changes that occur in the brain to understand how dementia illnesses develop.

One of the ongoing dementia studies, ROSMAP, combines longitudinal study groups from the Religious Orders Study (ROS) and the Rush Memory and Aging Project (MAP). Volunteer participants joined the studies in the 1990s and were free of dementia symptoms when they entered. They were evaluated annually and also agreed to autopsies after death to help researchers identify brain changes.

Now several decades later, researchers report that of those who have died, 40% had Alzheimer’s dementia. However, the neurological findings have been diverse. We hear a lot about amyloid plaques and tau tangles, which are often present in Alzheimer’s and were present in “most cases” reviewed. Yet researchers also found “other accumulations of different types of protein fragments or misfolded proteins,” along with damage to blood vessels.

“All of these other pathologies have a cumulative effect in the brains of people who have what we call Alzheimer’s dementia,” commented Rush researcher Julie A. Schneider for NIH.

Neuropathologies vary

NIH also points out that “the number and combinations of neuropathologies vary greatly among individuals, and the effects of these combinations on thinking and memory differ as well.”

Amyloid plaques and tau tangles are not absolute indicators of dementia. Data from the ROSMAP research indicate that nearly one in three older adults who were free of dementia during their lifetimes nevertheless had plaques and tangles at the time of death. The presence of multiple pathologies, though—including vascular injuries and other findings—does correlate to a higher risk of dementia and higher severity.

“New” dementias

NIH-funded researchers at the UK Sanders Brown Center and Alzheimer’s Research Disease Center have been focusing on some unique neuropathological profiles, notably PART and LATE:

  • Primary Age-Related Tauopathy (PART) describes the presence of tau tangles without amyloid plaques. It’s a common pathology, says NIH; it causes “mild cognitive decline at a slower rate than Alzheimer’s.”
  • Limbic-Predominant Age-Related TDP-43 Encephalopathy (LATE) describes abnormal clusters of the TDP-43 protein forming between neurons. It affects parts of the brain that are involved in memory.

Either of these neurological findings, combined with other pathologies, can result in more severe dementia illness. “By knowing that these different pathologies exist, the field is getting closer to unraveling the complexity of Alzheimer’s,” according to Peter T. Nelson, a researcher for NIH at the University of Kentucky.

Ongoing research may advance the ability to use biomarkers to diagnose dementias. It may also continue to grow our scientific understanding of interventions that can slow the development of dementias.

A focus on neurology

NIH research underscores important insights for dementia care teams in nursing homes. All dementias are not created equally. Importantly, the behavioral and psychological symptoms of dementia (BPSD) are not psychiatric illnesses and cannot be categorically treated as such (see Reducing Antipsychotic Use in Nursing Homes: A Paradigm Shift).

Underlying neurological conditions—such as which parts of the brain are affected, and which pathologies are present—can impact symptomatology and the course of the illness. Occasionally, what presents as dementia is a treatable illness such as normal pressure hydrocephalus, cerebrospinal fluid leak, or other condition. Medications and many other clinical factors come into play. Psychological factors can compound dementia symptoms. For all of these reasons, comprehensive, multi-disciplinary assessment of each resident is the touchstone for care.

In nursing homes, a neurologist is uniquely qualified to evaluate the neurological findings underlying each resident’s clinical dementia symptoms. Diagnosis comes before treatment. This is why GuideStar Eldercare decided to launch bedside neurology services in 2022. A focus on accurate diagnosis with the input of a neurologist can lead to more effective, person-centered care. It can help reduce suffering and improve quality of life for your residents.