Dementia can manifest in a variety of ways. People with Alzheimer’s disease typically have more than one type of dementia — such as frontotemporal lobar degeneration, or FTLD — which can make it hard for health care providers to correctly diagnose and care for them.
In a new study, Brown researchers sought to improve diagnoses by better understanding the symptoms of patients with both Alzheimer’s disease and FTLD, an often misdiagnosed type of dementia.
Previously, the researchers were unsure whether one disease’s symptoms would dominate over the other, according to lead author Daliah Ross, a postdoctoral fellow specializing in clinical neuropsychology at the Warren Alpert Medical School.
“We found that people really kind of had the combined symptom approach, where they had symptoms of both diseases,” Ross explained. Autopsies remain the standard to diagnose many neurodegenerative diseases.
Because FTLD often comes with strong neuropsychiatric symptoms — including behavioral and mood changes — it is often misdiagnosed as a “primary psychiatric problem,” such as depression, Ross said.
For the study, the researchers looked at patients who had autopsy-confirmed Alzheimer’s, FTLD or both conditions. They used data from 29 Alzheimer’s disease research centers, which was gathered through the National Alzheimer’s Coordinating Center.
To analyze the data, Ross and her team compared the likelihood of presenting with any one neuropsychiatric symptom among the three different groups.
According to co-author Edward Huey — professor of psychiatry and human behavior, director of the Memory and Aging Program at Butler Hospital and the associate director of the Center for Alzheimer’s Disease Research at Brown — the study’s findings can help to identify comorbid Alzheimer’s and FTLD in patients and differentiate individuals with either condition.
“We have pretty good biomarkers for Alzheimer’s disease. We don’t have that for FTLD,” Huey said.
“In real clinical settings, it is common for patients to have multiple pathologies, but these groups are understudied and therefore difficult to diagnose based on symptom presentations,” Grace Goodwin, a predoctoral neuropsychology resident at Warren Alpert who was not involved with the study, wrote in an email to The Herald.
Goodwin added that the study’s findings “brings us one step closer to improving diagnosis and treatment in this patient population.”
The study also has implications for the caregivers of individuals with Alzheimer’s and FTLD.
“When people have more than one of these diseases, they can have a much more complicated illness, and neuropsychiatric symptoms in particular are really burdensome on patients and their care partners,” Ross said. “So it’s important to better understand what we might expect in terms of neuropsychiatric symptoms in these diseases.”
According to Ross, a limitation of the study is that it only examined data from the last medical visit prior to death for people in the NACC database. In her future projects, Ross is interested in looking at data for the three groups over time.
Huey hopes future studies further explore the symptoms that help differentiate the two conditions. The study identified apathy, personality change and disinhibition as three major areas in which the diseases present differently, according to Huey.
Alzheimer’s disease is one of the most common neurodegenerative disorders that typically occurs later in life, according to Ross. Individuals diagnosed with Alzheimer’s disease are often older than individuals with FTLD, he added.
“There are a lot of different pathologies or illnesses that can happen in advanced aging that cause neurodegeneration … that cause cells in your brain to die, and based on what’s causing that, there are different diseases,” Ross explained.
Assistant Professor of Neuroimmunology and Brain Science Ted Wilson, who was not involved with the study, noted the significance of this study for his own research, in which he focuses on developing blood-based biomarkers for neurological diseases.
“This data that they’ve generated confirms what we’ve observed,” Wilson explained. “Namely, that there’s a substantial heterogeneity when it comes to the precise picture of neuropathology that’s present across older individuals.”
“This understanding is of critical importance to clinicians in guiding clinical treatments and care,” he added.
