Deans' stroke musings: Acoustic Enhancement of Sleep Slow Oscillations and Concomitant Memory Improvement in Older Adults

Changing stroke rehab and research worldwide now.Time is Brain! trillions and trillions of neurons that DIE each day because there are NO effective hyperacute therapies besides tPA(only 12% effective). I have 523 posts on hyperacute therapy, enough for researchers to spend decades proving them out. These are my personal ideas and blog on stroke rehabilitation and stroke research. Do not attempt any of these without checking with your medical provider. Unless you join me in agitating, when you need these therapies they won't be there.

What this blog is for:

My blog is not to help survivors recover, it is to have the 10 million yearly stroke survivors light fires underneath their doctors, stroke hospitals and stroke researchers to get stroke solved. 100% recovery. The stroke medical world is completely failing at that goal, they don't even have it as a goal. Shortly after getting out of the hospital and getting NO information on the process or protocols of stroke rehabilitation and recovery I started searching on the internet and found that no other survivor received useful information. This is an attempt to cover all stroke rehabilitation information that should be readily available to survivors so they can talk with informed knowledge to their medical staff. It lays out what needs to be done to get stroke survivors closer to 100% recovery. It's quite disgusting that this information is not available from every stroke association and doctors group.

Sunday, April 30, 2017

Acoustic Enhancement of Sleep Slow Oscillations and Concomitant Memory Improvement in Older Adults

Sounds like it might be useful post-stroke but I bet you'll have to convince your doctor of that.
Original study back in April, 2013 but I bet your doctor and hospital did not do one fucking thing with it.

Study: Listening to Certain Sounds Seems to Improve Sleep April 2013

Acoustic Enhancement of Sleep Slow Oscillations and Concomitant Memory Improvement in Older Adults

Gentle sound stimulation—such as the rush of a waterfall—synchronized to the rhythm of brain waves significantly enhanced deep sleep in older adults and improved their ability to recall words, reports a new Northwestern Medicine study.

Deep sleep is critical for memory consolidation. But beginning in middle age, deep sleep decreases substantially, which scientists believe contributes to memory loss in aging.
The sound stimulation significantly enhanced deep sleep in participants and their scores on a memory test.
"This is an innovative, simple and safe non-medication approach that may help improve brain health," said senior author Dr. Phyllis Zee, professor of neurology at Northwestern University Feinberg School of Medicine and a Northwestern Medicine sleep specialist. "This is a potential tool for enhancing memory in older populations and attenuating normal age-related memory decline."
The study was published March 8 in Frontiers in Human Neuroscience.
In the study, 13 participants 60 and older received one night of acoustic stimulation and one night of sham stimulation. The sham stimulation procedure was identical to the acoustic one, but participants did not hear any noise during sleep. For both the sham and acoustic stimulation sessions, the individuals took a memory test at night and again the next morning. Recall ability after the sham stimulation generally improved on the morning test by a few percent. However, the average improvement was three times larger after pink-noise stimulation.
The older adults were recruited from the Cognitive Neurology and Alzheimer's Disease Center at Northwestern.
The degree of slow wave sleep enhancement was related to the degree of memory improvement, suggesting slow wave sleep remains important for memory, even in old age.
Although the Northwestern scientists have not yet studied the effect of repeated nights of stimulation, this method could be a viable intervention for longer-term use in the home, Zee said.
Previous research showed acoustic simulation played during deep sleep could improve memory consolidation in young people. But it has not been tested in older adults.
The new study targeted older individuals—who have much more to gain memory-wise from enhanced deep sleep—and used a novel sound system that increased the effectiveness of the sound stimulation in older populations.
The study used a new approach, which reads an individual's brain waves in real time and locks in the gentle sound stimulation during a precise moment of neuron communication during deep sleep, which varies for each person.
During deep sleep, each brain wave or oscillation slows to about one per second compared to 10 oscillations per second during wakefulness.
Giovanni Santostasi, a study coauthor, developed an algorithm that delivers the sound during the rising portion of slow wave oscillations. This stimulation enhances synchronization of the neurons' activity.
After the sound stimulation, the older participants' slow waves increased during sleep.
Larger studies are needed to confirm the efficacy of this method and then "the idea is to be able to offer this for people to use at home," said first author Nelly Papalambros, a Ph.D. student in neuroscience working in Zee's lab. "We want to move this to long-term, at-home studies."
Northwestern scientists, under the direction of Dr. Roneil Malkani, assistant professor of neurology at Feinberg and a Northwestern Medicine sleep specialist, are currently testing the acoustic stimulation in overnight sleep studies in patients with memory complaints. The goal is to determine whether acoustic stimulation can enhance memory in adults with mild cognitive impairment.
Previous studies conducted in individuals with mild cognitive impairment in collaboration with Ken Paller, professor of psychology at the Weinberg College of Arts and Sciences at Northwestern, have demonstrated a possible link between their sleep and their memory impairments.

Explore further: Sound waves boost older adult' memory, deep sleep

More information: Nelly A. Papalambros et al. Acoustic Enhancement of Sleep Slow Oscillations and Concomitant Memory Improvement in Older Adults, Frontiers in Human Neuroscience (2017). DOI: 10.3389/fnhum.2017.00109

Read more at: https://medicalxpress.com/news/2017-04-pink-noise-synced-brain-deepens.html#jCp

Nelly A. Papalambros¹,

Giovanni Santostasi¹,

Roneil G. Malkani¹,

Rosemary Braun^2,3,

Sandra Weintraub⁴,

Ken A. Paller⁵ and

Phyllis C. Zee^1*

¹Center for Circadian and Sleep Medicine, Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
²Biostatistics Division, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
³Department of Engineering Sciences and Applied Mathematics, Northwestern University, Evanston, IL, USA
⁴Cognitive Neurology and Alzheimer’s Disease Center and Department of Psychiatry and Behavioral Sciences, Northwestern University, Chicago, IL, USA
⁵Department of Psychology, Northwestern University, Evanston, IL, USA

Acoustic stimulation methods applied during sleep in young adults can increase slow wave activity (SWA) and improve sleep-dependent memory retention. It is unknown whether this approach enhances SWA and memory in older adults, who generally have reduced SWA compared to younger adults. Additionally, older adults are at risk for age-related cognitive impairment and therefore may benefit from non-invasive interventions. The aim of this study was to determine if acoustic stimulation can increase SWA and improve declarative memory in healthy older adults. Thirteen participants 60–84 years old completed one night of acoustic stimulation and one night of sham stimulation in random order. During sleep, a real-time algorithm using an adaptive phase-locked loop modeled the phase of endogenous slow waves in midline frontopolar electroencephalographic recordings. Pulses of pink noise were delivered when the upstate of the slow wave was predicted. Each interval of five pulses (“ON interval”) was followed by a pause of approximately equal length (“OFF interval”). SWA during the entire sleep period was similar between stimulation and sham conditions, whereas SWA and spindle activity were increased during ON intervals compared to matched periods during the sham night. The increases in SWA and spindle activity were sustained across almost the entire five-pulse ON interval compared to matched sham periods. Verbal paired-associate memory was tested before and after sleep. Overnight improvement in word recall was significantly greater with acoustic stimulation compared to sham and was correlated with changes in SWA between ON and OFF intervals. Using the phase-locked-loop method to precisely target acoustic stimulation to the upstate of sleep slow oscillations, we were able to enhance SWA and improve sleep-dependent memory storage in older adults, which strengthens the theoretical link between sleep and age-related memory integrity.

Introduction

As the population of adults over the age of 65 continues to increase, it is critical to further elucidate the relationships between sleep and cognitive function. Age-related cognitive decline can be seen across multiple cognitive domains such as executive function, processing speed, and memory (Schaie et al., 1998). A decline in hippocampal-dependent declarative memory, or the ability to consciously recall facts and episodic knowledge, is a frequent complaint of older adults (Newson and Kemps, 2006) and a potential precursor to dementia (Hohman et al., 2011). Age-related decline in declarative memory typically has been attributed to failures in encoding and/or retrieval of information (Luo and Craik, 2008), whereas consolidation has been under-emphasized. Although age is a significant risk factor for memory loss and dementia, there may be modifiable factors that also contribute to memory decline, such as sleep.

Deep sleep, also known as slow wave sleep (SWS), may be particularly relevant for understanding the intersection of sleep, aging, and memory. SWS is characterized by slow waves in the delta frequency band (0.5–4 Hz) of at least 75 μV. Slow wave activity (SWA), a quantitative physiologic measure of SWS, is the electroencephalographic (EEG) power in the delta frequency range. In young individuals, sleep has been shown to play an important role in memory consolidation, and sleep deprivation can disrupt the ability to encode and consolidate new memories (Rasch and Born, 2013). SWS appears to be particularly conducive to hippocampal-dependent memory consolidation (Plihal and Born, 1997; Born et al., 2006; Marshall and Born, 2007). Furthermore, selective suppression of sleep slow waves leads to poor memory encoding (Van Der Werf et al., 2011) and visuomotor learning (Landsness et al., 2009). The theory of active system consolidation of declarative memories suggests that slow oscillations drive repeated reactivation of memory traces in the hippocampus (Born and Wilhelm, 2012; Rasch and Born, 2013). Consolidation, which results in strengthening of cortical representations and decreased dependence on the hippocampus for retrieval (Paller, 2009), may be facilitated when the activity of thalamo-cortical network is synchronized via slow oscillations (Diekelmann et al., 2009). In addition to SWS, Rapid Eye Movement (REM) sleep may also contribute to consolidation of episodic (Rauchs et al., 2004) and procedural memories (Plihal and Born, 1997). At any rate, a key question is whether specific changes in sleep contribute to memory impairment in aging populations.

Sleep in older adults is characterized by frequent awakenings and a prominent reduction in REM, SWS, and SWA (Ohayon et al., 2004; Edwards et al., 2010). Although word pair recall in older adults has been associated with duration of non-REM/REM sleep cycles (Mazzoni et al., 1999), REM sleep deprivation has been shown to have no effect on memory consolidation (Hornung et al., 2007). Much is unknown about the specific mechanisms of age-related changes in sleep physiology, but recent evidence suggests that gray-matter atrophy in the medial prefrontal cortex underlies age-related decline in SWA (Mander et al., 2013b). SWA has indeed been shown to be associated with declarative memory performance in older adults (Westerberg et al., 2012; Mander et al., 2013b). Given this evidence implicating SWA, it is biologically plausible that memory storage can be enhanced in older adults by promoting slow wave synchronization during sleep.

Manipulation of SWS provides a powerful tool both to investigate causal relationships between sleep and memory, and to improve memory consolidation. Whereas slow-oscillatory electrical stimulation can increase SWA and boost memory in older adults (Westerberg et al., 2015), this methodology has practical limitations, due to setup complexity and potential safety issues that would impede long-term use. In contrast, acoustic stimulation has distinct advantages, such as feasibility for repeated at-home use and individualized adjustments that could be automated in real-time. In addition, SWA during stimulation can readily be analyzed, which is not the case for electrical stimulation. Pulses of pink noise targeted to the upstate of intrinsically generated slow waves increased SWA and improved word pair recall in young adults (Tononi et al., 2010; Ngo et al., 2013b; Ong et al., 2016), but such studies using acoustic stimulation in older adults are lacking.

The goal of the present study was to determine whether acoustic stimulation in sleep can boost SWA and improve memory in older adults. We developed an automated, adaptive algorithm that can monitor the endogenous slow oscillatory activity in the EEG and phase-lock the timing of acoustic stimuli to a desired phase of the slow wave (Santostasi et al., 2016). This phase-locked loop (PLL) has been previously utilized to deliver intervals of acoustic pulses to the upstate of the slow wave during SWS that resulted in an increase in SWA in young adults during daytime naps (Ong et al., 2016; Santostasi et al., 2016). However, the feasibility of this method has not been tested in older adults. We examined changes in memory using a randomized crossover design comparing one night of acoustic stimulation to one night of sham stimulation; in both conditions, participants completed a declarative memory test before and after sleep.