Long-term and within-day variability of working memory performance and EEG in individuals

详细信息	查看全文 | 推荐本文 |

• 作者：Alan Gevins ; ^{alan@sfbri.org} ; Linda K. McEvoy² ; Michael E. Smith¹ ; Cynthia S. Chan ; Lita Sam-Vargas ; Cliff Baum ; Aaron B. Ilan
• 关键词：Working memory ; EEG ; Long-term variability ; Circadian variability ; Drug effects ; Individual differences
• 刊名：Clinical Neurophysiology
• 出版年：2012
• 期刊代码：61_13882457
• 类别：med
• 出版时间：July, 2012
• 卷：123
• 期：7
• 页码：1291-1299
• 文件大小：375 K

摘要

Objective

Assess individual-subject long-term and within-day variability of a combined behavioral and EEG test of working memory.

Methods

EEGs were recorded from 16 adults performing n-back working memory tasks, with 10 tested in morning and afternoon sessions over several years. Participants were also tested after ingesting non-prescription medications or recreational substances. Performance and EEG measures were analyzed to derive an Overall score and three constituent sub-scores characterizing changes in performance, cortical activation, and alertness from each individual鈥檚 baseline. Long-term and within-day variability were determined for each score; medication effects were assessed by reference to each individual鈥檚 normal day-to-day variability.

Results

Over the several year period, the mean Overall score and sub-scores were approximately zero with standard deviations less than one. Overall scores were lower and their variability higher in afternoon relative to morning sessions. At the group level, alcohol, diphenhydramine and marijuana produced significant effects, but there were large individual differences.

Conclusions

Objective working memory measures incorporating performance and EEG are stable over time and sensitive at the level of individual subjects to interventions that affect neurocognitive function.

Significance

With further research these measures may be suitable for use in individualized medical care by providing a sensitive assessment of incipient illness and response to treatment.