Béatrice Garcin1, Emmanuelle Volle2, Aurélie Funkiewiez3, Bruce L Miller4, Bruno Dubois5, Richard Levy6. 1. Institut du Cerveau et de la Moelle épinière (ICM), UPMC UMRS 1127, Inserm U 1127, CNRS UMR 7225, Paris, France; Neurology department, Memory and Aging center, Pitié-Salpêtrière Hospital, AP-HP, Paris, France. Electronic address: beatrice.garcin@aphp.fr. 2. Institut du Cerveau et de la Moelle épinière (ICM), UPMC UMRS 1127, Inserm U 1127, CNRS UMR 7225, Paris, France. 3. Neurology department, Memory and Aging center, Pitié-Salpêtrière Hospital, AP-HP, Paris, France. 4. Memory and Aging Center, University of California, San Francisco, United States. 5. Institut du Cerveau et de la Moelle épinière (ICM), UPMC UMRS 1127, Inserm U 1127, CNRS UMR 7225, Paris, France; Neurology department, Memory and Aging center, Pitié-Salpêtrière Hospital, AP-HP, Paris, France. 6. Institut du Cerveau et de la Moelle épinière (ICM), UPMC UMRS 1127, Inserm U 1127, CNRS UMR 7225, Paris, France; Neurology department, Memory and Aging center, Pitié-Salpêtrière Hospital, AP-HP, Paris, France; Neurology department, Behavioral Neuro-psychiatry Unit, Pitié-Salpêtrière Hospital, AP-HP, Paris, France.
Abstract
BACKGROUND: Patients with neurodegenerative diseases affecting the frontal lobes have difficulties in categorization tasks, such as the similarity tasks. They give two types of unusual response to the question: "In what way are an orange and a banana alike?", either a differentiation ("one is yellow, the other is orange") or a concrete similarity ("they are sweet"). OBJECTIVE: To characterize the categorization deficit of frontal patients and develop a short diagnostic tool to assess the nature of these difficulties. METHOD: We analyzed the responses provided by frontal and non-frontal neurodegenerative patients in a novel verbal similarity task (SimiCat). We included 40 frontal patients with behavioral variant fronto-temporal dementia (bvFTD) and progressive supranuclear palsy (PSP), 23 patients with Alzheimer's disease (AD) and 41 healthy matched controls. Responses that did not correspond to the expected taxonomic category (e.g.: fruits) were considered as errors. RESULTS: All patients groups were impaired at the SimiCat test compared to controls. Differentiation errors were specific to frontal patients. Receiver operating characteristic analyses showed that a cut-off of two differentiation errors or more achieved 85% sensitivity of 100% specificity to discriminate bvFTD from AD. A short version of the test (<5 min) showed similar discriminative validity as the full version. CONCLUSION: Differentiation responses were specific to frontal patients. The SimiCat demonstrates good discriminative validity to differentiate between bvFTD and AD. The short version of the test is a promising diagnostic tool that will need validation in future studies.
BACKGROUND:Patients with neurodegenerative diseases affecting the frontal lobes have difficulties in categorization tasks, such as the similarity tasks. They give two types of unusual response to the question: "In what way are an orange and a banana alike?", either a differentiation ("one is yellow, the other is orange") or a concrete similarity ("they are sweet"). OBJECTIVE: To characterize the categorization deficit of frontalpatients and develop a short diagnostic tool to assess the nature of these difficulties. METHOD: We analyzed the responses provided by frontal and non-frontal neurodegenerativepatients in a novel verbal similarity task (SimiCat). We included 40 frontal patients with behavioral variant fronto-temporal dementia (bvFTD) and progressive supranuclear palsy (PSP), 23 patients with Alzheimer's disease (AD) and 41 healthy matched controls. Responses that did not correspond to the expected taxonomic category (e.g.: fruits) were considered as errors. RESULTS: All patients groups were impaired at the SimiCat test compared to controls. Differentiation errors were specific to frontal patients. Receiver operating characteristic analyses showed that a cut-off of two differentiation errors or more achieved 85% sensitivity of 100% specificity to discriminate bvFTD from AD. A short version of the test (<5 min) showed similar discriminative validity as the full version. CONCLUSION: Differentiation responses were specific to frontal patients. The SimiCat demonstrates good discriminative validity to differentiate between bvFTD and AD. The short version of the test is a promising diagnostic tool that will need validation in future studies.
Authors: Arthur Cassa Macedo; Luciano Inácio Mariano; Marina Isoni Martins; Clarisse Vasconcelos Friedlaender; Jesus Mística Ventura; João Victor de Faria Rocha; Sarah Teixeira Camargos; Francisco Eduardo Costa Cardoso; Paulo Caramelli; Leonardo Cruz de Souza Journal: Mov Disord Clin Pract Date: 2022-04-04