failed to reach significanceP = 0.069
Midbrain volume loss was only observed for preclinical SCA2 compared to controls ( U = 70, z = −2.553, P = 0.015, r = −0.44), while volume differences between patients and controls marginally failed to reach significance after correction for multiple comparisons ( U = 150, z = −2.005, P = 0.069, r = −0.30).