The Utility of ACE-III in a Heterogeneous Early Onset Dementia Clinic Population (P6.201)

OBJECTIVE: The aims of this study were to investigate the utility of ACE-III in predicting dementia diagnoses in EOD, and to investigate correlation between ACE-III scores and regional perfusion changes on 99mTc-HMPAO-SPECT imaging. BACKGROUND: Early onset dementia (EOD) is defined as a functionally relevant cognitive impairment with age of onset less than 65 years. A third version of the widely used cognitive screening tool Addenbrooke’s Cognitive Examination (ACE-III) has recently been validated, but its utility in EOD has not been investigated. DESIGN/METHODS: We identified patients attending a tertiary cognitive clinic who fulfilled consensus criteria for diagnoses of EOD. Age, sex and educationally-matched individuals attending clinic during the same time period with subjective memory impairment (SMI) were identified and included as controls. ACE-III scores were compared in patients with dementia and controls. Correlations with 99mTc-HMPAO-SPECT imaging were investigated. RESULTS: 79 cases were included: Alzheimer’s disease (AD) n=30, behavioural variant frontotemporal dementia (bv-FTD) n=13, Primary Progressive Aphasia (PPA) n=9, Posterior Cortical Atrophy (PCA) n=10, and 17 SMI/controls. Mean total ACE-III scores were significantly lower in patients with EOD compared to controls (p<0.0001). A cut-off score of 88 yielded a high sensitivity (94.1[percnt]) and specificity (91.9[percnt]) for diagnosing dementia. The lowest sensitivity was for diagnosing bv-FTD (84.6[percnt]). The only significant difference observed between dementia groups was in visuo-spatial sub-scores which were significantly lower in PCA patients compared to AD, bv-FTD, and PPA patients (p<0.0001). The presence of a posterior pattern on 99mTc-HMPAO-SPECT imaging was associated with significantly lower attention (p<0.0001) and visuospatial sub-scores (p<0.0001). An anterior pattern was associated with a trend towards lower fluency subscores (p=0.087). CONCLUSIONS: The recently validated ACE-III is a reliable cognitive screening tool in EOD. More sensitive and specific tests are required for differential diagnosis in EOD. Disclosure: Dr. Elamin has nothing to disclose. Dr. Holloway has nothing to disclose. Dr. Khan has nothing to disclose. Dr. Bak has nothing to disclose.