Incremental value of amyloid-PET versus CSF in the diagnosis of Alzheimer's disease.

PURPOSE: To compare the incremental diagnostic value of amyloid-PET and CSF (Aß42, tau, and phospho-tau) in AD diagnosis in patients with mild cognitive impairment (MCI) or mild dementia, in order to improve the definition of diagnostic algorithm. METHODS: Two independent dementia experts provided etiological diagnosis and relative diagnostic confidence in 71 patients on 3 rounds, based on (1) clinical, neuropsychological, and structural MRI information alone; (2) adding one biomarker (CSF amyloid and tau levels or amyloid-PET with a balanced randomized design); and (3) adding the other biomarker. RESULTS: Among patients with a pre-biomarker diagnosis of AD, negative PET induced significantly more diagnostic changes than amyloid-negative CSF at both rounds 2 (CSF 67%, PET 100%, P = 0.028) and 3 (CSF 0%; PET 78%, P < 0.001); PET induced a diagnostic confidence increase significantly higher than CSF on both rounds 2 and 3. CONCLUSIONS: Amyloid-PET should be prioritized over CSF biomarkers in the diagnostic workup of patients investigated for suspected AD, as it provides greater changes in diagnosis and diagnostic confidence. TRIAL REGISTRATION: EudraCT no.: 2014-005389-31.

Do Beliefs about the Pathogenetic Role of Amyloid Affect the Interpretation of Amyloid PET in the Clinic.

BACKGROUND: Beliefs of dementia experts about the pathogenic role of amyloid in Alzheimer's disease (AD) may affect the use of amyloid positron emission tomography (PET). OBJECTIVE: To assess the role attributed to amyloid in AD pathogenesis by Italian dementia experts, and whether this modulates the impact of amyloid PET results in their diagnostic workup. METHODS: 22 dementia experts rated their beliefs about the pathogenic role of amyloid. Then, we asked them to rate the probability of change in diagnosis based on the result of amyloid PET for 7 case vignettes, depicting patients who initially received a diagnosis based on a comprehensive workup and later received amyloid PET results consistent or inconsistent with the clinical picture. RESULTS: 55% of the experts assigned a dominant role to amyloid, and 32% attributed a similar role to amyloid and tau in AD pathogenesis. The probability of change in diagnosis ranged from 17% (SD = 21.6) for cases with consistent to 51% (SD = 34) for cases with inconsistent PET versus clinical data. Diagnostic change was not biased by the clinicians' beliefs about AD pathogenesis. CONCLUSIONS: This work supports an unbiased interpretation of amyloid PET across different beliefs about the pathogenic role of amyloid, and a belief-independent reluctance to change diagnosis in cases where change is expected and recommended.

Self-rated and assessed cognitive functions in epilepsy: impact on quality of life.

AIM OF THE STUDY: To compare the effects of perceived and assessed cognitive functions on quality of life (QoL) in patients with epilepsy (PWE). METHODS: The study analyzed the data from a series of PWE who compiled the Quality of Life in Epilepsy-89 Inventory (QOLIE-89) and the Multiple Ability Self-Report Questionnaire (MASQ) for QoL and perceived cognitive abilities, respectively. The State-Trait Anxiety and Beck Depression inventories were used to assess mood. Neuropsychological tests evaluated abstract reasoning, attention, conceptual-motor tracking, constructional praxis, language, verbal and non-verbal memory, abstraction, category shifting, verbal fluency, and visual-spatial abilities. RESULTS: The QOLIE-89 overall score was predicted by the Mood and Attention and Executive Functions factors and MASQ scores, explaining 38, 6, and 4% of its variance, while disease duration, seizure frequency, and schooling determined 16%. The QOLIE-89 Psychosocial, Cognitive, and Physical Performance sub-domains related to mood. The Cognitive and Physical Performance factors also related to the MASQ and Attention and Executive Functions factor scores, respectively. CONCLUSIONS: In PWE, self-rated and assessed cognitive deficits may influence QoL, explaining 10% of its variance irrespective from mood and clinical variables. Treating cognitive deficits and their perception may help improve QoL.