IC‐P‐120: MEDIAL TEMPORAL LOBE ATROPHY SCALE: NORMATIVE VALUES FOR ITALIAN POPULATION

Matteo Cotta Ramusino, Daniele Altomare, Alfredo Costa, Cristina Festari, Giovanni B. Frisoni, Marina Boccardi, Center for Cognitive and Behavioral Disorders, C. Mondino National Neurological Institute, Pavia, Italy; Istituto di Ricovero e Cura a Carattere Scientifico, Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy; University of Brescia, Brescia, Italy; University of Geneva, Geneva, Switzerland. Contact e-mail: giovanni.frisoni@gmail.com Background:The medial temporal lobe atrophy scale (MTA) is a 0to-4 visual rating scale for assessing the degree of hippocampal atrophy. Despite it is widely used due to its ease of employment, to date normative values are still missing. Methods: A trained rater, showing an excellent inter-rater agreement (ICC1⁄40.892; 95% CI: 0.723-0.958) with an expert rater, assessed coronal-T1 MR scans of the 936 cognitively healthy persons from the Italian Brain Normative Archive Study, and provided MTA scores for both hemispheres. Subjects (age: mean6SD: 50.2614.7; range: 2084) were selected retrospectively for having MMSE>26 and/or CDR1⁄40. We provided the normative data by age decades based on the percentile distribution, and investigated the correlation between MTA scores and APOE genotype, when the latter was available (56.3%). Results: MTA score (mean6SD: 0.660.7 for both sides) had a skewed distribution, half of the sample scoring 0 (on the right: n1⁄4480, 51.3%; on the left: n1⁄4475, 50.7%), and less than 10% scoring more than 1 (on the right: n1⁄471, 7.6%; on the left: n1⁄465, 6.9%). No significant difference was observed between sides in MTA scores (p1⁄41.000). The 90 percentile cut-off of the age-specific distribution increased from 1 (at age 20-59) to 2 (at age 60-79) and then up to 4 for subjects over 80s (Figure). No significant difference was observed between APOε4 carriers and noncarriers, neither in the whole sample (p1⁄40.23 right; p1⁄40.88 left), nor in the subsets over 60 (p1⁄40.96 right; p1⁄40.72 left). Conclusions: This study provides the first normative values for MTA in the general population. According to the literature, our data suggest the presence of different age-related cut-offs and, thus, the need to consider different thresholds depending on age. References: 1. Scheltens P et al. Atrophy of medial temporal lobes on MRI in "probable" Alzheimer’s disease and normal ageing: diagnostic value and neuropsychological correlates. J Neurol Neurosurg Psychiatry. 1992; 55(10):967-972. 2. Galluzzi S et al. The Italian Brain Normative Archive of structural MR scans: norms for medial temporal atrophy and white matter lesions. Aging Clin Exp Res. 2009; 21(4-5):266-276.