Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea.
Medical Science Research Institute, Kyung Hee University College of Medicine, Seoul, Republic of Korea.
Alzheimers Res Ther. 2022 Mar 8;14(1):39. doi: 10.1186/s13195-022-00978-w.
Basic studies suggest that olfactory dysfunction and functional near-infrared spectroscopy (fNIRS) can be used as tools for the diagnosis of mild cognitive impairment (MCI); however, real-world evidence is lacking. We investigated the potential diagnostic efficacy of olfactory-stimulated fNIRS for early detection of MCI and/or Alzheimer disease (AD).
We conducted a patient-level, single-group, diagnostic interventional trial involving elderly volunteers (age >60 years) suspected of declining cognitive function. Patients received open-label olfactory-stimulated fNIRS for measurement of oxygenation difference in the orbitofrontal cortex. All participants underwent amyloid PET, MRI, Mini-Mental State Examination (MMSE), and Seoul Neuropsychological Screening Battery (SNSB).
Of 97 subjects, 28 (28.9%) were cognitively normal, 32 (33.0%) had preclinical AD, 21 (21.6%) had MCI, and 16 (16.5%) had AD. Olfactory-stimulated oxygenation differences in the orbitofrontal cortex were associated with cognitive impairment; the association was more pronounced with cognitive severity. Olfactory-stimulated oxygenation difference was associated with MMSE (adjusted β [aβ] 1.001; 95% CI 0.540-1.463), SNSB language and related function (aβ, 1.218; 95% CI, 0.020-2.417), SNSB memory (aβ, 1.963; 95% CI, 0.841-3.084), SNSB frontal/executive function (aβ, 1.715; 95% CI, 0.401-3.029) scores, standard uptake value ratio from amyloid PET (aβ, -10.083; 95% CI, -19.063 to -1.103), and hippocampal volume from MRI (aβ, 0.002; 95% CI, 0.001-0.004). Olfactory-stimulated oxygenation difference in the orbitofrontal cortex was superior in diagnosing MCI and AD (AUC, 0.909; 95% CI, 0.848-0.971), compared to amyloid PET (AUC, 0.793; 95% CI, 0.694-0.893) or MRI (AUC, 0.758; 95% CI, 0.644-0.871).
Our trial showed that olfactory-stimulated oxygenation differences in the orbitofrontal cortex detected by fNIRS were associated with cognitive impairment and cognitive-related objectives. This novel approach may be a potential diagnostic tool for patients with MCI and/or AD.
CRIS number, KCT0006197 .
基础研究表明，嗅觉功能障碍和近红外光谱功能成像（fNIRS）可作为诊断轻度认知障碍（MCI）的工具；然而，目前缺乏实际证据。我们研究了嗅觉刺激 fNIRS 对早期检测 MCI 和/或阿尔茨海默病（AD）的潜在诊断功效。
我们进行了一项患者水平的、单组的、诊断性干预试验，纳入了疑似认知功能下降的老年志愿者（年龄＞60 岁）。患者接受了嗅觉刺激 fNIRS 测量眶额皮质的氧合差异。所有参与者均接受了淀粉样蛋白 PET、MRI、简易精神状态检查（MMSE）和首尔神经心理筛选测试（SNSB）。
在 97 名受试者中，28 名（28.9%）认知正常，32 名（33.0%）有临床前 AD，21 名（21.6%）有 MCI，16 名（16.5%）有 AD。眶额皮质的嗅觉刺激氧合差异与认知障碍相关；与认知严重程度的相关性更为显著。嗅觉刺激的氧合差异与 MMSE（调整后的β[ aβ]1.001；95%CI 0.540-1.463）、SNSB 语言和相关功能（aβ，1.218；95%CI，0.020-2.417）、SNSB 记忆（aβ，1.963；95%CI，0.841-3.084）、SNSB 额叶/执行功能（aβ，1.715；95%CI，0.401-3.029）评分、淀粉样蛋白 PET 的标准摄取比值（aβ，-10.083；95%CI，-19.063 至-1.103）和 MRI 的海马体积（aβ，0.002；95%CI，0.001-0.004）相关。与淀粉样蛋白 PET（AUC，0.793；95%CI，0.694-0.893）或 MRI（AUC，0.758；95%CI，0.644-0.871）相比，嗅觉刺激的眶额皮质氧合差异在诊断 MCI 和 AD 方面更具优势（AUC，0.909；95%CI，0.848-0.971）。
我们的试验表明，fNIRS 检测到的眶额皮质嗅觉刺激的氧合差异与认知障碍和认知相关指标有关。这种新方法可能是 MCI 和/或 AD 患者的潜在诊断工具。
CRIS 编号，KCT0006197。
