White Matter Hyperintensities and Cognitive Impairment in Healthy and Pathological Aging: A Quantified Brain MRI Study

Abstract

KeywordsWhite matter hyperintensity · Alzheimer dementia · Mild cognitive impairment · Vascular cognitive impairment Abstract Background: Brain changes involving the white matter (WM), often an indication of cerebrovascular pathology, are frequently seen in patients with mild cognitive impairment (MCI) and Alzheimer disease (AD). Few studies have examined possible cognitive domain-or groupspecific cognitive effects of WM pathology in old age, MCI, and AD. Objective: Our purpose was to examine the relationship between WM hyperintensities (WMH), a typical marker for WM pathology, and cognitive functioning in healthy old age and pathological aging using quantified MRI data. Methods: We utilized multidomain neuropsychological data and quantified MRI data from a sample of 42 cognitively healthy older adults and 44 patients with MCI/ AD (total n = 86). Results: After controlling for age and education, WMH in the temporal and parieto-occipital lobes was associated with impairments in processing speed and parietooccipital pathology with verbal memory impairment in the whole sample. Additionally, temporal WMH was associated with impaired processing speed in the patient group specifically. Conclusions: WM pathology is strongly associated with impaired processing speed, and our results indicate that these impairments arise from WMH in the temporal and parieto-occipital regions. In MCI and AD patients with temporal WMH, processing speed impairments are especially prominent. The results of this study increase our knowledge of cognitive repercussions stemming from temporal and/or parieto-occipital WM pathology in healthy and pathological aging.

Effects of White Matter Hyperintensities on Verbal Fluency in Healthy Older Adults and MCI/AD

“…Possibly, the most relevant one is that no group-specific associations were seen for the MCI/AD patient group. This is in contrast with our previous results, as we have previously reported indications of a cumulative effect of WM pathology in the frontal areas on general cognitive functioning in AD patients specifically (Kaskikallio et al, 2019b). We have also found indications of similar group-specific cumulative effects of frontal and temporal WMH volumes on processing speed (Kaskikallio et al, 2019a(Kaskikallio et al, , 2020.…”

“…A special focus was on examining possible groupwise effects, i.e., would there be differences in the effects of WM pathology between cognitively healthy and MCI/AD patients. The sample utilized here is a portion of the sample that has been used previously (Kaskikallio et al, 2019a(Kaskikallio et al, , 2020, with the quantified MRI being utilized in Kaskikallio et al (2019b).…”

“…Overall, the research literature regarding the effects of WM pathology on verbal fluency in AD is quite limited, and previous studies have contained fairly small samples. We have previously examined effects of WM pathology on both general cognitive functioning ( Kaskikallio et al, 2019a ) as well as on specific cognitive domains ( Kaskikallio et al, 2019b , 2020 ) in cognitively healthy adults and patients with MCI or AD. In these studies, verbal fluency was not included in the verbal function domain score ( Kaskikallio et al, 2019b , 2020 ) due to relatively low shared variance with the other verbal tasks in factor analysis—thus supporting the view that VF tasks tap additional cognitive processes such as executive functions (e.g., Henry and Crawford, 2004 ; Aita et al, 2016 ).…”

Construction and validation of a cerebral white matter hyperintensity probability map of older Koreans

“…Furthermore, both WPMs may not be directly applicable to Asians because they were constructed from Caucasians only, since the brain shape ( Lee et al, 2016 ) and the risk of cerebrovascular diseases and WMH are different between Caucasians and Asians ( Feldmann et al, 1990 ). Volume of the WMH in the current sample was smaller than that reported in the previous studies on healthy older Caucasians ( Kaskikallio et al, 2020 , Raz et al, 2012 ).…”

A ketogenic supplement improves white matter energy supply and processing speed in mild cognitive impairment

“…Slower processing speed in the placebo group may be attributable to disease progression over the six months. Indeed, WM pathology in MCI is associated with impaired processing speed [42]. There was no significant association between ketone uptake by the fornix and memory, but there was a strong correlation with processing speed.…”