Objective. To evaluate the metabolic correlates of lifetime sport practice in ALS through brain 18FFDG-
PET.
Methods. 131 patients completed a questionnaire about lifetime exposures, including physical
activity related to sports, hobbies and occupations, and underwent brain 18F-FDG-PET. Exposure to
sports was expressed as MET (Metabolic Equivalent of Task). We considered only regular practice
(at least 2 hours/week, for at least three months). We compared brain metabolism between two
groups: subjects who did not report regular sport practice during life (N-group) and patients who
did (Y-group). The resulting significant clusters were used in each group as seed regions in a
interregional correlation analysis (IRCA) to evaluate the impact of lifetime sport practice on brain
networks typically involved by the neurodegenerative process of ALS. Each group was compared to
healthy controls (HC, n=40).
Results. We found a significant, relative cerebellar hypermetabolism in the N-group compared to
the Y-group. The metabolism of such cerebellar cluster resulted correlated to more significant and
widespread metabolic changes in areas known to be affected by ALS (i.e. frontotemporal regions
and corticospinal tracts) in the N-group as compared to the Y-group, despite the same level of
disability as expressed by the ALS FRS-R. Such findings resulted independent of age, sex, site of
onset (bulbar/spinal), presence/absence of C9ORF72 expansion, cognitive status and physical
activity related to hobbies and occupations. When compared to HC, the N-group showed more
widespread metabolic changes than the Y-group in cortical regions known to be relatively
hypometabolic in ALS patients as compared to HC.
Conclusions. We hypothesize that patients of the N-group might cope better with the
neurodegenerative process, since they show more widespread metabolic changes as compared to the
Y-group, despite the same level of disability. Nevertheless, further studies are necessary to
corroborate this hypothesis.
