| 1. |
- Ferreira, Daniel, et al.
(författare)
-
The interactive effect of demographic and clinical factors on hippocampal volume : A multicohort study on 1958 cognitively normal individuals
- 2017
-
Ingår i: Hippocampus. - : Wiley. - 1050-9631 .- 1098-1063. ; 27:6, s. 653-667
-
Tidskriftsartikel (refereegranskat)abstract
- Alzheimer's disease is characterized by hippocampal atrophy. Other factors also influence the hippocampal volume, but their interactive effect has not been investigated before in cognitively healthy individuals. The aim of this study is to evaluate the interactive effect of key demographic and clinical factors on hippocampal volume, in contrast to previous studies frequently investigating these factors in a separate manner. Also, to investigate how comparable the control groups from ADNI, AIBL, and AddNeuroMed are with five population-based cohorts. In this study, 1958 participants were included (100 AddNeuroMed, 226 ADNI, 155 AIBL, 59 BRC, 295 GENIC, 279 BioFiNDER, 398 PIVUS, and 446 SNAC-K). ANOVA and random forest were used for testing between-cohort differences in demographic-clinical variables. Multiple regression was used to study the influence of demographic-clinical variables on hippocampal volume. ANCOVA was used to analyze whether between-cohort differences in demographic-clinical variables explained between-cohort differences in hippocampal volume. Age and global brain atrophy were the most important variables in explaining variability in hippocampal volume. These variables were not only important themselves but also in interaction with gender, education, MMSE, and total intracranial volume. AddNeuroMed, ADNI, and AIBL differed from the population-based cohorts in several demographic-clinical variables that had a significant effect on hippocampal volume. Variability in hippocampal volume in individuals with normal cognition is high. Differences that previously tended to be related to disease mechanisms could also be partly explained by demographic and clinical factors independent from the disease. Furthermore, cognitively normal individuals especially from ADNI and AIBL are not representative of the general population. These findings may have important implications for future research and clinical trials, translating imaging biomarkers to the general population, and validating current diagnostic criteria for Alzheimer's disease and predementia stages.
|
|
| 2. |
- Velickaite, Vilma
(författare)
-
Analysis of regional atrophy on brain imaging compared with cognitive function in the elderly and in patients with dementia – cross-sectional and longitudinal evaluation
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- During aging, brain changes are not homogeneous throughout the entire brain, but are related to changes in the morphology of neurons, as well as to changes in the tissue density, and are specific to each region of the brain. Dementia is a broad category of brain disorders with a set of symptoms including memory, visual-spatial and language problems. Most types of dementia are slowly progressing, and by the time the person shows signs of the disorder, processes in the brain are already advanced. Dementia reduces not only the person’s ability to perform everyday activities, it also increases mortality rates significantly. Because of the increasing incidence of dementia, possible prevention and treatment of dementia as early as possible are essential.The aim of the PhD project is to compare a quantitative and qualitative image analysis of regional cerebral atrophy with cognitive function in the elderly persons.In paper I, 58 persons participated (84–88 years old) from the ULSAM (Uppsala Longitudinal Study of Adult Men) cohort. They underwent CT of the brain, cognitive testing and LP. This study showed that AD biomarkers seem to be less informative in subjects with an advanced age.In papers II–IV, the cohort included subjects from the PIVUS (Prospective Investigation of the Vasculature in Uppsala Seniors) study.Paper II showed that at age 75, gender and education are confounders for MTA rating. Subjects with abnormal right MTA, but normal MMSE scores had developed worse MMSE scores 5 years later.Paper III showed that automated rating of MTA could be used in clinical practice to support the radiological evaluation. Automated rating of PA and F-GCA should be tested in future studies.In paper IV, we found a mild age-associated decrease in regional brain volumes in this healthy cohort with well-preserved cognitive and executive functions.In conclusion, the included studies in this thesis compare regional atrophy grades in the brain on CT and MRI and clinical data and provide knowledge that may be used in future investigations that aim to detect dementia in its early stages.
|
|
| 3. |
|
|
| 4. |
- Voevodskaya, Olga, et al.
(författare)
-
The effects of intracranial volume adjustment approaches on multiple regional MRI volumes in healthy aging and Alzheimer's disease
- 2014
-
Ingår i: Frontiers in Aging Neuroscience. - : Frontiers Media SA. - 1663-4365 .- 1663-4365. ; 6, s. 264-
-
Tidskriftsartikel (refereegranskat)abstract
- In neurodegeneration research, normalization of regional volumes by intracranial volume (ICV) is important to estimate the extent of disease-driven atrophy. There is little agreement as to whether raw volumes, volume-to-ICV fractions or regional volumes from which the ICV factor has been regressed out should be used for volumetric brain imaging studies. Using multiple regional cortical and subcortical volumetric measures generated by Freesurfer (51 in total), the main aim of this study was to elucidate the implications of these adjustment approaches. Magnetic resonance imaging (MRI) data were analyzed from two large cohorts, the population-based PIVUS cohort (N = 406, all subjects age 75) and the Alzheimer disease Neuroimaging Initiative (ADNI) cohort (N = 724). Further, we studied whether the chosen ICV normalization approach influenced the relationship between hippocampus and cognition in the three diagnostic groups of the ADNI cohort (Alzheimer's disease, mild cognitive impairment, and healthy individuals). The ability of raw vs. adjusted hippocampal volumes to predict diagnostic status was also assessed. In both cohorts raw volumes correlate positively with ICV, but do not scale directly proportionally with it. The correlation direction is reversed for all volume-to-ICV fractions, except the lateral and third ventricles. Most gray matter fractions are larger in females, while lateral ventricle fractions are greater in males. Residual correction effectively eliminated the correlation between the regional volumes and ICV and removed gender differences. The association between hippocampal volumes and cognition was not altered by ICV normalization. Comparing prediction of diagnostic status using the different approaches, small but significant differences were found. The choice of normalization approach should be carefully considered when designing a volumetric brain imaging study.
|
|
| 5. |
- Wahlund, Lars-Olof, et al.
(författare)
-
Strukturell hjärnavbildning kan förbättra diagnostiken vid demens
- 2013
-
Ingår i: Läkartidningen. - 0023-7205 .- 1652-7518. ; 110:CEY4
-
Tidskriftsartikel (refereegranskat)abstract
- Ökad kunskap om demenssjukdomar leder till att de diagnostiska kriterierna förändras. Diagnostiken kan förbättras med hjälp av hjärnavbildningsfynd.Med datortomografi (DT) och magnetisk resonanstomografi (MRT) kan medial temporallobsatrofi, global cerebral atrofi och förändringar i vit substans visualiseras och kvantifieras.För att ge optimal information om dessa förändringar krävs ett strukturerat radiologiskt DT-/MR-utlåtande. Imaging Cognitive Impairment Network (ICINET) har som huvudmål att föreslå ett standardiserat MRT-protokoll och kliniska utvärderingsverktyg (visuella skattningsskalor för MRT och DT).
|
|
