The volumetric profile of the brainstem in ALS, PLS, disease and healthy controls. Corners: Estimate marginal means of the medulla, pons, midbrain are plotted for each study group adjusted for age, gender, education and total intracranial volumes. Centre: Percentage volumetric change is plotted with reference to healthy controls. ALS_T1: ALS patients first time point, ALS_T2: ALS patients second time point, FTD: patients with frontotemporal dementia, HC: healthy controls, PLS: patients with primary lateral sclerosis.