(FTD) in findings that may help physicians make this difficult diagnosis that affects adults in their prime.
“The assessment of WMH can aid differential diagnosis of bvFTD [behavioral-variant FTD] against other neurodegenerative conditions in the absence of vascular risk factors, especially when considering their spatial distribution,” said senior author Ramón Landin-Romero, PhD, Appenzeller Neuroscience Fellow, Frontotemporal Dementia Research Group, University of Sydney.
“Clinicians can ask for specific sequences in routine MRI scans to visually detect WMH,” said Dr. Landin-Romero, who is also a senior lecturer in the School of Psychology and Brain and Mind Center.
The study was published online Feb. 17 in Neurology.
Difficult diagnosis
“FTD is a collection of unrecognized young-onset (before age 65) dementia syndromes that affect people in their prime,” said Dr. Landin-Romero. He added that heterogeneity in progression trajectories and symptoms, which can include changes in behavior and personality, language impairments, and psychosis, make it a difficult disease to diagnose.
“As such, our research was motivated by the need of sensitive and specific biomarkers of FTD, which are urgently needed to aid diagnosis, prognosis, and treatment development,” he said.
Previous research has been limited; there have only been a “handful” of cohort and case studies and studies involving individuals with mutations in one FTD-causative gene.
FTD is genetically and pathologically complex, and there has been no clear correlation between genetic mutations/underlying pathology and clinical presentation, Dr. Landin-Romero said.
WMH are common in older individuals and are linked to increased risk for cognitive impairment and dementia. Traditionally, they have been associated with vascular risk factors, such as smoking and diabetes. “But the presentation of WMH in FTD and its associations with the severity of symptoms and brain atrophy across FTD symptoms remains to be established,” said Dr. Landin-Romero.
Higher disease severity
To explore the possible association, the researchers studied 129 patients with either bvFTD (n = 64; mean age, 64 years) or Alzheimer’s disease (n = 65; mean age, 64.66 years).
Neuropsychological assessments, medical and neurologic examinations, clinical interview, and structural brain MRI were conducted for all patients, who were compared with 66 age-, sex-, and education-matched healthy control persons (mean age, 64.69 years).
Some participants in the FTD, Alzheimer’s disease, and healthy control groups (n = 54, 44, and 26, respectively) also underwent genetic screening. Postmortem pathology findings were available for a small number of FTD and Alzheimer’s disease participants (n = 13 and 5, respectively).
The medical history included lifestyle and cardiovascular risk factors, as well as other health and neurologic conditions and medication history. Hypertension, hypercholesterolemia, diabetes, and smoking were used to assess vascular risk.
The FTD and Alzheimer’s disease groups did not differ with regard to disease duration (3.55 years; standard deviation, 1.75, and 3.24 years; SD, 1.59, respectively). However, disease severity was significantly higher among those with FTD than among those with Alzheimer’s disease, as measured by the FTD Rating Scale Rasch score (–0.52; SD, 1.28, vs. 0.78; SD, 1.55; P < .001).
Compared with healthy controls, patients in the FTD and Alzheimer’s disease groups scored significantly lower on the Addenbrooke’s Cognitive Examination–Revised (ACE-R) or ACE-III scale. Patients with Alzheimer’s disease showed “disproportionately larger deficits” in memory and visuospatial processing, compared with those with FTD, whereas those with FTD performed significantly worse than those with Alzheimer’s disease in the fluency subdomain.
A larger number of patients in the FTD group screened positive for genetic abnormalities than in the Alzheimer’s disease group; no participants in the healthy control group had genetic mutations.