Affiliations: [a] Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine and Johns Hopkins Bayview Medical Center, Baltimore, MD, USA | [b] Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA | [c] Department of Radiology Johns Hopkins University School of Medicine and Johns Hopkins Bayview Medical Center, Baltimore, MD, USA | [d] Department of Neurology, Johns Hopkins University School of Medicine and Johns Hopkins Bayview Medical Center, Baltimore, MD, USA | [e] Department of Health Sciences Research, Division of Epidemiology and Department of Neurology, Mayo Clinic, Rochester, MN, USA
Correspondence:
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Correspondence to: Milap A. Nowrangi, MD, MBe, Department of Psychiatry, Johns Hopkins Bayview Medical Center, 5300 Alpha Commons Drive, 4th Floor, Baltimore, MD 21224, USA. Tel.: +1 410 550 2294; Fax: +1 410 550 1407; E-mail: mnowran1@jhmi.edu.
Abstract: Impairment in executive function (EF) is commonly found in Alzheimer's disease (AD) and mild cognitive impairment (MCI). Atlas-based diffusion tensor imaging (DTI) methods may be useful in relating regional integrity to EF measures in MCI and AD. Sixty-six participants (25 normal controls, 22 MCI, and 19 AD) received DTI scans and clinical evaluation. DTI scans were applied to a pre-segmented atlas and fractional anisotropy (FA) and mean diffusivity (MD) were calculated. ANOVA was used to assess group differences in frontal, parietal, and cerebellar regions. For regions differing between groups (p < 0.01), linear regression examined the relationship between EF scores and regional FA and MD. Anisotropy and diffusivity in frontal and parietal lobe white matter structures were associated with EF scores in MCI and only frontal lobe structures in AD. EF was more strongly associated with FA than MD. The relationship between EF and anisotropy and diffusivity was strongest in MCI. These results suggest that regional white matter integrity is compromised in MCI and AD and that FA may be a better correlate of EF than MD.
