Background: Clinical subtypes of mild cognitive impairment (MCI) may represent different underlying aetiologies.
Methods: This European, multicentre, memory clinic based study (DESCRIPA) of non-demented subjects investigated whether MCI subtypes have different brain correlates on MRI and whether the relation between subtypes and brain pathology is modified by age. Using visual rating scales, medial temporal lobe atrophy (MTA) (0–4) and white matter hyperintensities (WMH) (0–30) were assessed.
Results: Severity of MTA differed between MCI subtypes (p<0.001), increasing from a mean of 0.8 (SD 0.7) in subjective complaints (n = 77) to 1.3 (0.8) in non-amnestic MCI (n = 93), and from 1.4 (0.9) in single domain amnestic MCI (n = 70) to 1.7 (0.9) in multiple domain amnestic MCI (n = 89). The association between MCI subtype and MTA was modified by age and mainly present in subjects >70 years of age. Severity of WMH did not differ between MCI subtypes (p = 0.21). However, the combination of MTA and WMH differed between MCI subtypes (p = 0.02)
Conclusion: We conclude that MCI subtypes may have different brain substrates, especially in older subjects. Isolated MTA was mainly associated with amnestic MCI subtypes, suggesting AD as the underlying cause. In non-amnestic MCI, the relatively higher prevalence of MTA in combination with WMH may suggest a different pathophysiological origin.
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Funding The study was funded by the European Commission within the 5th framework programme (QLRT-2001-2455). The study was partly supported (HS) by EVO grant from Kuopio University Hospital, Kuopio, Finland, 5772720. The European commission funded the study as a concerted action but had no role in study design or analysis of the data.
Competing interests None.
Ethics approval The study was approved by the local medical ethics committee in each centre.
Provenance and Peer review Not commissioned; externally peer reviewed.