Magnetic resonance imaging study cannot individually distinguish individuals with mild cognitive impairment, mild Alzheimer's disease, and normal aging

Abstract

Elderly individuals with mild cognitive impairment (MCI) are part of a continuum between normal aging with its cognitive difficulties and fully-fledged dementia. However, there is a growing body of evidence suggesting that MCI might precede the onset of Alzheimer' s disease (AD). Longitudinal studies have demonstrated that subjects with MCI present a progression rate of 10-15% per year to AD, contrasting with 1-2%, in a similar analysis, in the general population using a similar age range 1 .Declarative memory is related to the involvement of mesial structures of the temporal lobe, especially the hippocampus 2,3 . Studies using magnetic resonance imaging (MRI) may provide in vivo analysis of specific regions of the temporal lobe showing a strong correlation between abnormal neuroimaging findings and the scores obtained on cognitive tests 4,5 . A number of authors have reported that volumetric-structural study and spectroscopy analysis might be useful in the investigation of patients with MCI in order to diagnose patients with a higher risk of developing AD 6-8 .In advanced phases of AD, major hippocampus atrophy with a decrease in N-acetyl aspartate (NAA) and an increase ABSTRACTObjective: To evaluate the volumetric and spectroscopy aspects of hippocampus in patients with mild Alzheimer's disease (AD) and mild cognitive impairment (MCI). Methods: A series of patients older than 65 years and with memory deficit were studied. Results: The evocation of words test presented a significant reduction in the number of words recalled by the patients with MCI and mild AD as compared with the control group. Bilateral reduction of the hippocampus volume in the AD group was observed when compared to the control group. There were no statistical differences in the values of NAA/Cr, mI/Cr, Cho/Cr and mI/NAA between the groups. Conclusions: Magnetic resonance imaging study failed to individually distinguish patients with MCI, mild AD and normal aging. However, patients with mild AD presented loss of asymmetry between the right and left hippocampus, and a reduction in hippocampus volume.Key words: Alzheimer disease, dementia, mild cognitive impairment, hippocampus, magnetic resonance imaging, spectroscopy. RESUMO Objetivo:Avaliar volume e espectroscopia do hipocampo em pacientes com doença de Alzheimer leve e declínio cognitivo leve. Métodos: Foi estudada uma série de pacientes com 65 anos de idade ou mais, com déficit de memória. Resultados: O teste de evocação de palavras mostrou redução significativa no número de palavras lembradas pelos pacientes com declínio cognitivo leve e doença de Alzheimer leve, em comparação com o grupo controle. Foi observada redução bilateral do volume do hipocampo no grupo com doença de Alzheimer quando comparado com o grupo controle. Não houve diferença estatística nos valores de NAA/Cr, mI/Cr, Cho/Cr e mI/NAA entre os grupos. Conclusão: Estudo pela ressonância magnética não diferencia individualmente os pacientes com declínio cognitivo leve, doença de Alzheimer leve e envelhecimento normal. No en...

Hippocampal volume and hippocampal angle (a more practical marker) in mild cognitive impairment: A case-control magnetic resonance imaging study

“…[ 26 27 28 ] However, other recent studies revealed that HV difference was not significant between two groups. [ 29 30 ]…”

1H-MRS asymmetry changes in the anterior and posterior cingulate gyrus in patients with mild cognitive impairment and mild Alzheimer's disease

“…1 H-MRS of the hippocampal region in AD and MCI patients demonstrated a decrease in NAA and increased mI, while decreased NAA/Cr ratios were predictive of future conversion from MCI to AD [10,11]. By contrast, no significant differences in NAA/Cr, mI/Cr, and Cho/Cr of hippocampus were also found in MCI, mild AD, and normal aging [12]. Regional metabolite changes in normal ageing individuals and those with MCI and AD were reported to reflect a gradual process of brain degeneration that initially affects the left, but not right, hippocampus, resulting in asymmetry changes on 1 H-MRS [13].…”

Psychiatric neuroimaging research in Brazil: historical overview, current challenges, and future opportunities

“…[133][134][135] Studies of healthy aging, MCI, and AD are relevant in this context because they are at the interface between psychiatry and neurology; neuroimaging investigations in this field have been carried out by groups at HCFMUSP, [136][137][138] FMRP-USP, 139 and UNIFESP 140,141 in the state of Sã o Paulo, as well at the UFMG, 142 UFRJ, 143,144 and the Federal University of Pernambuco (UFPE). 145 A map of Brazil showing the official names and location of each of the institutions cited above is provided in Figure 1.…”