Parkinson's disease with mild cognitive impairment: severe cortical thinning antedates dementia

Brain Imaging Behav. 2019 Feb;13(1):180-188. doi: 10.1007/s11682-017-9751-6.

Abstract

Mild cognitive impairment (MCI) in Parkinson's disease (PD) is a risk factor for dementia and thus, it is of interest to elucidate if specific patterns of atrophy in PD-MCI patients are associated with a higher risk of developing dementia. We aim to define pattern(s) of regional atrophy in PD-MCI patients who developed dementia during 31 months of follow-up using cortical thickness analysis Twenty-three PD-MCI patients and 18 controls underwent brain MRI and completed a neuropsychological examination at baseline, PD-MCI patients were followed after a 31 month follow-up in order to assess their progression to dementia. At follow up, 8 PD-MCI patients had converted to dementia (PD-MCI converters) whereas 15 remained as PD-MCI (PD-MCI non-converters). All patients were at least 60 years old and suffered PD ≥ 10 years. There were no baseline differences between the two groups of patients in clinical and neuropsychological variables. The cortex of PD-MCI converters was thinner than that of PD-MCI non-converters, bilaterally in the frontal, insula and the left middle temporal areas, also displaying a more widespread pattern of cortical thinning relative to the controls. This study shows that aged and long-term PD patients with MCI who convert to dementia in the short-mid term suffer a thinning of the cortex in several areas (frontal cortex, and middle temporal lobe and insula), even when their cognitive impairment was similar to that of PD-MCI non-converters. Thus, MRI analysis of cortical thickness may represent a useful measure to identify PD-MCI patients at a higher risk of developing dementia.

Keywords: Cortical thickness; Dementia; Mild cognitive impairment; Parkinson’s disease.

MeSH terms

  • Aged
  • Cerebral Cortex / diagnostic imaging*
  • Cerebral Cortex / pathology
  • Cognitive Dysfunction / diagnostic imaging*
  • Cognitive Dysfunction / etiology
  • Cognitive Dysfunction / pathology
  • Dementia / diagnostic imaging*
  • Dementia / etiology
  • Dementia / pathology
  • Disease Progression
  • Female
  • Follow-Up Studies
  • Humans
  • Image Processing, Computer-Assisted
  • Magnetic Resonance Imaging
  • Male
  • Neuropsychological Tests
  • Organ Size
  • Parkinson Disease / diagnostic imaging*
  • Parkinson Disease / pathology
  • Parkinson Disease / psychology*
  • Prognosis