Atrophy patterns on MRI can reliably predict three neuropathological subtypes of Alzheimer’s disease (AD): typical, limbic-predominant, or hippocampal-sparing. A method to enable their investigation in the clinical routine is still lacking. We aimed to (1) validate the combined use of visual rating scales for identification of AD subtypes; (2) characterise these subtypes at baseline and over two years; and (3) investigate how atrophy patterns and non-memory cognitive domains contribute to memory impairment. AD patients were classified as either typical AD (n = 100), limbic-predominant (n = 33), or hippocampal-sparing (n = 35) by using the Scheltens’ scale for medial temporal lobe atrophy (MTA), the Koedam’s scale for posterior atrophy (PA), and the Pasquier’s global cortical atrophy scale for frontal atrophy (GCA-F). A fourth group with no atrophy was also identified (n = 30). 230 healthy controls were also included. There was great overlap among subtypes in demographic, clinical, and cognitive variables. Memory performance was more dependent on non-memory cognitive functions in hippocampal-sparing and the no atrophy group. Hippocampal-sparing and the no atrophy group showed less aggressive disease progression. Visual rating scales can be used to identify distinct AD subtypes. Recognizing AD heterogeneity is important and visual rating scales may facilitate investigation of AD heterogeneity in clinical routine.

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The results of the study: (a) provide relevant data about the process of validation of the MDS PD-MCI criteria, (b) reinforce the hypothesis that PD-MCI is more frequent than previous studies showed without applying MDS criteria, and (c) confirm that PD-MCI is a risk factor for the onset of dementia. Finally, the study shows that neurological impairment, educational level and memory impairment were predictors for the progression of cognitive impairment.

Friedreich ataxia (FRDA) is the most frequent of the inherited ataxias. However, very few studies have examined the cognitive status of patients with genetically defined FRDA. Our aim was to study cognitive performance of FRDA patients taking into account the motor problems characteristic of this clinical population. Thirty-six FRDA patients were administered a comprehensive neuropsychological battery measuring multiple domains: processing speed, attention, working memory, executive functions, verbal and visual memory, visuoperceptive and visuospatial skills, visuoconstructive functions, and language. Thirty-one gender, age, years of education, and estimated IQ-matched healthy participants served as control subjects. All participants were native Spanish speakers. Patients showed decreased motor and mental speed, problems in conceptual thinking, a diminished verbal fluency, deficits in acquisition of verbal information and use of semantic strategies in retrieval, visuoperceptive and visuoconstructive problems, and poor action naming. Scores on the depression inventory were significantly higher in patients than controls, but depression did not account for group differences in cognitive performance. The observed pattern of neuropsychological impairment is indicative of executive problems and parieto-temporal dysfunction. Neuropathological and neuroimaging studies with FRDA patients have reported only mild anomalies in cerebral hemispheres. Thus, cognitive impairment in FRDA is probably caused by the interruption of the cerebro-cerebellar circuits that have been proposed as the anatomical substrate of the cerebellar involvement in cognition.