Processing speed is correlated with cerebral health markers in the frontal lobes as quantified by neuroimaging

Neuroimage. 2010 Jan 15;49(2):1190-9. doi: 10.1016/j.neuroimage.2009.09.052. Epub 2009 Sep 28.

Abstract

We explored relationships between decline in cognitive processing speed (CPS) and change in frontal lobe MRI/MRS-based indices of cerebral integrity in 38 healthy adults (age 57-90 years). CPS was assessed using a battery of four timed neuropsychological tests: Grooved Pegboard, Coding, Symbol Digit Modalities Test and Category Fluency (Fruits and Furniture). The neuropsychological tests were factor analyzed to extract two components of CPS: psychomotor (PM) and psychophysical (PP). MRI-based indices of cerebral integrity included three cortical measurements per hemisphere (GM thickness, intergyral and sulcal spans) and two subcortical indices (fractional anisotropy (FA), measured using track-based spatial statistics (TBSS), and the volume of hyperintense WM (HWM)). MRS indices included levels of choline-containing compounds (GPC+PC), phosphocreatine plus creatine (PCr+Cr), and N-acetylaspartate (NAA), measured bilaterally in the frontal WM bundles. A substantial fraction of the variance in the PM-CPS (58%) was attributed to atrophic changes in frontal WM, observed as increases in sulcal span, declines in FA values and reductions in concentrations of NAA and choline-containing compounds. A smaller proportion (20%) of variance in the PP-CPS could be explained by bilateral increases in frontal sulcal span and increases in HWM volumes.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Anisotropy
  • Aspartic Acid / analogs & derivatives
  • Aspartic Acid / metabolism
  • Choline / metabolism
  • Cognition / physiology*
  • Creatine / metabolism
  • Female
  • Frontal Lobe / anatomy & histology*
  • Frontal Lobe / physiology*
  • Humans
  • Magnetic Resonance Imaging
  • Magnetic Resonance Spectroscopy
  • Male
  • Middle Aged
  • Nerve Fibers, Myelinated / physiology
  • Neuropsychological Tests
  • Organ Size
  • Phosphocreatine / metabolism
  • Time Factors

Substances

  • Phosphocreatine
  • Aspartic Acid
  • N-acetylaspartate
  • Creatine
  • Choline