The Prodromal Phase of Frontotemporal Lobar Degeneration: Mild Cognitive Impairment of the FTLD Type (P07.165)

Objective: To investigate the frequency and characteristics of a recognizable clinical phase of mild cognitive impairment (MCI) in patients with a diagnosis of Frontotemporal Lobar Degeneration (FLTD) and to investigate the clinical, psychometric, and structural MRI predictors of conversion to dementia in this population. Background Although many investigators believe that most neurodegenerative dementias have an initial symptomatic phase consistent with MCI, there has been relatively little study of non-Alzheimer forms of MCI. Design/Methods: A consecutive series of patients with a clinical diagnosis of FTLD were evaluated comprehensively, including functional assessment to determine whether their overall clinical status was best defined as MCI or dementia. Cortical thickness analysis was employed to measure regional atrophy. Results: Of the 124 patients in our FTLD cohort, 43 patients were classified as having a clinical status of MCI at initial presentation and 81 were classified as having a clinical status of dementia. Of the 43 patients who presented with MCI, 20 patients have since converted to dementia. The majority of patients (34) with MCI clinical status had one of the primary progressive aphasia phenotypes, with the remainder (9) having a behavioral variant FTLD (bvFTLD) phenotype; all but 1 of the bvFTLD patients converted to dementia. All MCI-FTLD patients demonstrated atrophy detectable on quantitative MRI. Conclusions: In our experience, it is relatively common for aphasic FTLD to present in a prodromal clinical phase consistent with MCI, but relatively less common for behavioral variant FTLD to present in this stage. MCI of the FTLD type usually has specific recognizable syndromic clinical characteristics and structural MRI changes that are often distinct from MCI due to Alzheimer9s disease. Additional analyses are in progress to identify the best predictors of conversion to dementia. Supported by: NIA R01-AG029411, NIA P50-AG005134, Alzheimer9s Association, 2NCRR P41-RR14075, U24-RR021382, the MIND Institute. Disclosure: Dr. Domoto-Reilly has nothing to disclose. Dr. Negreira has nothing to disclose. Dr. Brickhouse has nothing to disclose. Dr. Sapolsky has nothing to disclose. Dr. Dickerson has received personal compensation for activities with Pfizer as a consultant.