title: Memory improvement via slow-oscillatory stimulation during sleep in older adults.
abstract: We examined the intriguing but controversial idea that disrupted sleep-dependent consolidation contributes to age-related memory decline. Slow-wave activity during sleep may help strengthen neural connections and provide memories with long-term stability, in which case decreased slow-wave activity in older adults could contribute to their weaker memories. One prediction from this account is that age-related memory deficits should be reduced by artificially enhancing slow-wave activity. In young adults, applying transcranial current oscillating at a slow frequency (0.75 Hz) during sleep improves memory. Here, we tested whether this procedure can improve memory in older adults. In 2 sessions separated by 1 week, we applied either slow-oscillatory stimulation or sham stimulation during an afternoon nap in a double-blind, crossover design. Memory tests were administered before and after sleep. A larger improvement in word-pair recall and higher slow-wave activity was observed with slow-oscillatory stimulation than with sham stimulation. This is the first demonstration that this procedure can improve memory in older adults, suggesting that declarative memory performance in older adults is partly dependent on slow-wave activity during sleep.
authors.affiliation: Department of Psychology, Texas State University, San Marcos, TX, USA; Department of Psychology, Northwestern University, Evanston, IL, USA; Interdepartmental Neuroscience Program, Northwestern University, Evanston, IL, USA. Electronic address: cw54@txstate.edu.
authors.forename: Carmen E
authors.initials: CE
authors.lastname: Westerberg
authors.affiliation: Department of Psychology, Northwestern University, Evanston, IL, USA; Interdepartmental Neuroscience Program, Northwestern University, Evanston, IL, USA.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Florczak
authors.affiliation: Interdepartmental Neuroscience Program, Northwestern University, Evanston, IL, USA; Cognitive Neurology and Alzheimer's Disease Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA; Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: Sandra
authors.initials: S
authors.lastname: Weintraub
authors.affiliation: Interdepartmental Neuroscience Program, Northwestern University, Evanston, IL, USA; Cognitive Neurology and Alzheimer's Disease Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA; Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: M-Marsel
authors.initials: MM
authors.lastname: Mesulam
authors.affiliation: Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Lübeck, Germany.
authors.forename: Lisa
authors.initials: L
authors.lastname: Marshall
authors.affiliation: Interdepartmental Neuroscience Program, Northwestern University, Evanston, IL, USA; Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: Phyllis C
authors.initials: PC
authors.lastname: Zee
authors.affiliation: Department of Psychology, Northwestern University, Evanston, IL, USA; Interdepartmental Neuroscience Program, Northwestern University, Evanston, IL, USA.
authors.forename: Ken A
authors.initials: KA
authors.lastname: Paller
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001245:Association Learning; D001703:Biophysics; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004569:Electroencephalography; D005145:Face; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000628:therapy*; D009483:Neuropsychological Tests; D017286:Polysomnography; D021641:Recognition, Psychology; D012890:Sleep / Q000502:physiology*; D065908:Transcranial Direct Current Stimulation
keywords: Aging; Declarative memory; Electrical stimulation; Slow-wave sleep