P2–077: Presence of the APOE‐ε4 gene in patients with mild cognitive impairment: First report in Costa Rica

Abstract

Background: The majority of individuals referred to a Memory Clinic have subtle symptoms of cognitive impairment and from a clinical point of view most of them are not demented. Eventually, many of these individuals develop a form of dementia that is clinically detectable but some of them may remain stable for years, and the concern may even disappear. The EEG diagnostic tool presented here is designed to help the clinician to evaluate possible progress of the cognitive symptoms in MCI subjects over time. Methods: In an EEG database EEGs from 342 mild AD subjects and 181 MCI individuals have been entered. The EEG data from the MCI individuals was collected over a period of 7 years (2005)(2006)(2007)(2008)(2009)(2010)(2011). Over the course of 8 years these MCI individuals have been followed up. The MCI individuals were divided into three subgroups according to their clinical status at follow up: prodromal AD (pAD), stable MCI (sMCI), and other. The pAD and sMCI groups were compared by constructing a classifier by applying statistical pattern recognition to a large set of EEG features. Results: Of the 181 MCI individuals 70 were diagnosed with AD 1-7.7 years after the EEG measurement with a mean of 2 years. 79 remained MCI for at least 3 years, with a mean of 4.75 years and standard deviation of 1.00 year. The remaining 32 individuals had developed other types of dementia at follow up. The pAD-sMCI classifier indicates that using EEG it is possible to predict which of the MCI individuals will at a later time develop AD with accuracy of about 80%. Conclusions: Following a more substantial clinical validation and an easy access to the methodology, we expect this application of clinical EEG in support for differential diagnosis of mild cognitive impairment to become a realistic first step in the full clinical workup of patients who visit a memory clinic. The underlying technology is well known, widely available and inexpensive in relation to other imaging techniques.Background: The only medications indicated for treatment of mild AD are the cholinesterase inhibitors. The effects of the medicines are measured by cognitive tests and by caregiver reports but there are no direct biological means of evaluating treatment effects. A theoretically possible method is to measure the cholinergic response of these drugs in the brain. It has been proposed that the EEG changes seen in AD are primarily a reflection of cholinergic dysfunction. We postulate that by establishing a "cholinergic measure" in EEG registration, the treatment effects of cholinergic drugs could be estimated and thereby the treatment response. This is equivalent to performing an electrophysiological phenotyping (EPT) using EEG, the two phenotypes being responders and non-responders to cholinesterase inhibitor treatment. Methods: A large database of EEGs from mild AD patients was used in conjunction with the Mentis Cura Dementiagram TM in order to define the EPTs using a principal component analysis (PCA). A longitudinal study with 42 AD patients over 1-3 year...