Stephan Grimaldi1, Mohamed Boucekine2, Tatiana Witjas3, Frédérique Fluchère4, Mathilde Renaud5, Jean-Philippe Azulay4, Eric Guedj6, Alexandre Eusebio3. 1. Aix-Marseille Univ, APHM, CHU Timone, Department of Neurology and Movement Disorders, 13385, Marseille Cedex 05, France. Electronic address: stephan.grimaldi@ap-hm.fr. 2. Aix-Marseille Univ, EA 3279 - Self-perceived Health Assessment Research Unit, 13005, Marseille, France. 3. Aix-Marseille Univ, APHM, CHU Timone, Department of Neurology and Movement Disorders, 13385, Marseille Cedex 05, France; Aix Marseille Univ, CNRS, UMR 7289, Institut de Neurosciences de la Timone, 13385, Marseille, France. 4. Aix-Marseille Univ, APHM, CHU Timone, Department of Neurology and Movement Disorders, 13385, Marseille Cedex 05, France. 5. Aix-Marseille Univ, APHM, CHU Timone, Department of Neurology and Movement Disorders, 13385, Marseille Cedex 05, France; Service de Génétique Clinique, CHU de Nancy, Hôpitaux de Brabois, 54500, Vandoeuvre, France. 6. Aix-Marseille Univ, CNRS, Ecole Centrale Marseille, UMR, 7249, Institut Fresnel, Marseille, France; Aix-Marseille Univ, APHM, CHU Timone, Service Central de Biophysique et Médecine Nucléaire, 13385, Marseille Cedex 05, France; Aix-Marseille Univ, CERIMED, Bd Jean Moulin, 13005, Marseille, France.
Abstract
OBJECTIVE: The 2008 diagnostic criteria classify Multiple System Atrophy (MSA) patients in a predominantly parkinsonian (MSA-P) or cerebellar (MSA-C) type. Phenotypic descriptions have since highlighted a clinical heterogeneity among patients (e.g., mixed-type, cognitive impairment, atypical longer survival). This study attempts to identify different phenotypes of patients with MSA and to describe corresponding brain 18-FDG Positron Emission Tomography (PET) patterns. METHODS: Patients with a "probable" MSA diagnosis for whom a brain 18-FDG PET was performed were included. A retrospective analysis (from 2006 to 2017) was conducted using standardized data collection. We used Latent Class Analysis (LCA), an innovative statistical approach, to identify profiles of patients based on common clinical characteristics. Brain metabolism of different groups was studied at rest. RESULTS: Eighty-five patients were included. Three different profiles were revealed (entropy = 0.835): 1. extrapyramidal, axial, laryngeal-pharyngeal involvement (LPI) and cerebellar symptoms (n = 46, 54.1%); 2. cerebellar and LPI symptoms (n = 30, 35.3%); 3. cerebellar and cognitive symptoms (n = 9, 10.6%). Brain metabolism analyses (k > 89; p < 0.001) showed hypometabolism of the basal ganglia, frontal/prefrontal, temporal cortices and left posterior cerebellum in profile 1. In profile 2 there was hypometabolism of the medulla, prefrontal, temporal, cingular cortices, putamen and bilateral cerebellar hemispheres. In profile 3 there was hypometabolism of bilateral posterior cerebellar hemispheres and vermis. CONCLUSION: Beyond the two most common phenotypes of MSA, a third and particularly atypical profile with cerebellar and cognitive symptoms but without LPI involvement is described. These profiles are supported by different brain metabolic abnormalities which could be useful for diagnostic purposes.
OBJECTIVE: The 2008 diagnostic criteria classify Multiple System Atrophy (MSA) patients in a predominantly parkinsonian (MSA-P) or cerebellar (MSA-C) type. Phenotypic descriptions have since highlighted a clinical heterogeneity among patients (e.g., mixed-type, cognitive impairment, atypical longer survival). This study attempts to identify different phenotypes of patients with MSA and to describe corresponding brain 18-FDG Positron Emission Tomography (PET) patterns. METHODS:Patients with a "probable" MSA diagnosis for whom a brain 18-FDG PET was performed were included. A retrospective analysis (from 2006 to 2017) was conducted using standardized data collection. We used Latent Class Analysis (LCA), an innovative statistical approach, to identify profiles of patients based on common clinical characteristics. Brain metabolism of different groups was studied at rest. RESULTS: Eighty-five patients were included. Three different profiles were revealed (entropy = 0.835): 1. extrapyramidal, axial, laryngeal-pharyngeal involvement (LPI) and cerebellar symptoms (n = 46, 54.1%); 2. cerebellar and LPI symptoms (n = 30, 35.3%); 3. cerebellar and cognitive symptoms (n = 9, 10.6%). Brain metabolism analyses (k > 89; p < 0.001) showed hypometabolism of the basal ganglia, frontal/prefrontal, temporal cortices and left posterior cerebellum in profile 1. In profile 2 there was hypometabolism of the medulla, prefrontal, temporal, cingular cortices, putamen and bilateral cerebellar hemispheres. In profile 3 there was hypometabolism of bilateral posterior cerebellar hemispheres and vermis. CONCLUSION: Beyond the two most common phenotypes of MSA, a third and particularly atypical profile with cerebellar and cognitive symptoms but without LPI involvement is described. These profiles are supported by different brain metabolic abnormalities which could be useful for diagnostic purposes.