Laptinskaya Daria, Thurm Franka, Küster Olivia C, Fissler Patrick, Schlee Winfried, Kolassa Stephan, von Arnim Christine A F, Kolassa Iris-Tatjana
Clinical and Biological Psychology, Institute of Psychology and Education, Ulm University, Ulm, Germany.
Department of Psychology, University of Konstanz, Konstanz, Germany.
Front Aging Neurosci. 2018 Feb 2;10:5. doi: 10.3389/fnagi.2018.00005. eCollection 2018.
The auditory mismatch negativity (MMN) is an event-related potential (ERP) peaking about 100-250 ms after the onset of a deviant tone in a sequence of identical (standard) tones. Depending on the interstimulus interval (ISI) between standard and deviant tones, the MMN is suitable to investigate the pre-attentive auditory discrimination ability (short ISIs, ≤ 2 s) as well as the pre-attentive auditory memory trace (long ISIs, >2 s). However, current results regarding the MMN as an index for mild cognitive impairment (MCI) and dementia are mixed, especially after short ISIs: while the majority of studies report positive associations between the MMN and cognition, others fail to find such relationships. To elucidate these so far inconsistent results, we investigated the validity of the MMN as an index for cognitive impairment exploring the associations between different MMN indices and cognitive performance, more specifically with episodic memory performance which is among the most affected cognitive domains in the course of Alzheimer's dementia (AD), at baseline and at a 5-year-follow-up. We assessed the amplitude of the MMN for short ISI (stimulus onset asynchrony, SOA = 0.05 s) and for long ISI (3 s) in a neuropsychologically well-characterized cohort of older adults at risk of dementia (subjective memory impairment, amnestic and non-amnestic MCI; = 57). Furthermore, we created a novel difference score (ΔMMN), defined as the difference between MMNs to short and to long ISI, as a measure to assess the decay of the auditory memory trace, higher values indicating less decay. ΔMMN and MMN amplitude after long ISI, but not the MMN amplitude after short ISI, was associated with episodic memory at baseline ( = 0.38, = 0.003; = -0.27, = 0.047, respectively). ΔMMN, but not the MMN for long ISIs, was positively associated with episodic memory performance at the 5-year-follow-up ( = 0.57, = 0.013). The results suggest that the MMN after long ISI might be suitable as an indicator for the decline in episodic memory and indicate ΔMMN as a potential biomarker for memory impairment in older adults at risk of dementia.
听觉失匹配负波（MMN）是一种事件相关电位（ERP），在一系列相同（标准）音调中，偏差音调出现后约100 - 250毫秒达到峰值。根据标准音调和偏差音调之间的刺激间隔（ISI），MMN适用于研究前注意听觉辨别能力（短ISI，≤2秒）以及前注意听觉记忆痕迹（长ISI，>2秒）。然而，目前关于MMN作为轻度认知障碍（MCI）和痴呆症指标的结果不一，尤其是在短ISI之后：虽然大多数研究报告MMN与认知之间存在正相关，但其他研究未能发现这种关系。为了阐明这些迄今为止不一致的结果，我们通过探索不同MMN指标与认知表现之间的关联，更具体地说是与情景记忆表现（在阿尔茨海默病（AD）病程中受影响最严重的认知领域之一）在基线和5年随访时的关联，研究了MMN作为认知障碍指标的有效性。我们在一个具有良好神经心理学特征的有痴呆风险的老年人群队列（主观记忆障碍、遗忘型和非遗忘型MCI；n = 57）中评估了短ISI（刺激起始异步，SOA = 0.05秒）和长ISI（3秒）时MMN的振幅。此外，我们创建了一个新的差异分数（ΔMMN），定义为短ISI和长ISI时MMN之间的差异，作为评估听觉记忆痕迹衰退的指标，值越高表明衰退越少。长ISI后的ΔMMN和MMN振幅与基线时的情景记忆相关（分别为r = 0.38，p = 0.003；r = -0.27，p = 0.047）。在5年随访时，ΔMMN与情景记忆表现呈正相关（r = 0.57，p = 0.013），而长ISI时的MMN则不然。结果表明，长ISI后的MMN可能适合作为情景记忆衰退的指标，并表明ΔMMN是有痴呆风险的老年人记忆障碍的潜在生物标志物。
