Evaluation of patients with behavioral and cognitive complaints: misdiagnosis in frontotemporal dementia and Alzheimer's disease

BACKGROUND: Frontotemporal dementia (FTD) is a heterogeneous clinicopathological syndrome whose early diagnosis is critical for developing management strategies. OBJECTIVE: To analyze the variables associated with misdiagnosis in a group of patients with FTD, Alzheimer's disease (AD), and without neurodegenerative disorders (WND), all of whom were evaluated for behavioral and cognitive complaints. METHODS: A case-control study with FTD (n=10), probable AD (n=10) and WND (n=10) patients was carried out. The studied variables were disease duration, reason for referral, former diagnosis, behavioral and cognitive symptoms at evaluation, MMSE at the specialist evaluation, and follow-up outcome. The data were analyzed by ANOVA with Bonferroni post-hoc and by Pearson's Chi-Square tests. RESULTS: FTD patients and WND patients showed longer disease duration than AD patients; the main reasons for referral in the FTD group were behavioral, memory and memory plus language problems while all AD and 90% of the WND group were referred for memory. The FTD group had the highest rate of misdiagnosis and worst outcomes after the 12-month follow-up. The majority of AD and WND patients had memory symptoms, while FTD patients presented language (30%), memory and/or language (40%) problems on the evaluation. CONCLUSION: Difficulty in recognizing the main features of FTD and psychiatric disorders with memory impairment was observed. Clinicians tended to generalize memory complaints toward a single diagnosis, identifying almost all these patients as AD or leaving them undiagnosed.