scholarly journals Pathological slow-wave activity and impaired working memory binding in post-traumatic amnesia

2021 ◽  
Author(s):  
Emma-Jane Mallas ◽  
Nikos Gorgoraptis ◽  
Sophie Dautricourt ◽  
Yoni Pertzov ◽  
Gregory Scott ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Working Memory ◽  
Brain Injury ◽  
Slow Wave ◽  
Memory Function ◽  
Low Frequency ◽  
Wave Activity ◽  
Slow Wave Activity ◽  
Traumatic Amnesia ◽  
Post Traumatic

The mechanism by which information is bound together in working memory is a central question for cognitive neuroscience. This binding is transiently disrupted during periods of post-traumatic amnesia following significant head injuries. The reason for this impairment is unclear but may be due to electrophysiological changes produced by head impacts. These are common and include pathological low frequency activity, which is associated with poorer neurological outcomes and may disrupt cortical communication. Here, we investigate associative memory binding during post-traumatic amnesia and test the hypothesis that misbinding is caused by a disruption in cortical communication produced by the pathological slowing of brain activity. Thirty acute moderate-severe traumatic brain injury patients (mean time since injury = 10 days) and 26 healthy controls were tested with a precision working memory paradigm that required the association of object and location information. A novel entropy ratio measure was calculated from behavioural performance. This provided a continuous measure of the degree of misbinding and the influence of distracting information. Resting state EEG was used to assess the electrophysiological effects of traumatic brain injury. Patients in post-traumatic amnesia showed abnormalities in working memory function and made significantly more misbinding errors than patients who were not in post-traumatic amnesia and controls. Patients showed a higher entropy ratio in the distribution of spatial responses, indicating that working memory recall was abnormally biased by the locations of non-target items suggesting a specific impairment of object and location binding. Slow wave activity was increased following traumatic brain injury. Increases in the delta-alpha ratio indicative of an increase in low frequency power specifically correlated with binding impairment in working memory. In contrast, although connectivity was increased in the theta band and decreased in the alpha band after traumatic brain injury, this did not correlate with working memory impairment. Working memory and electrophysiological abnormalities both normalised at six-month follow-up, in keeping with a transient increase in slow-wave activity causing post-traumatic amnesia that impaired working memory function. These results show that patients in post-traumatic amnesia show high rates of working memory misbinding that are associated with a pathological shift towards lower frequency oscillations.

scholarly journals Pilot Study of Propofol-induced Slow Waves as a Pharmacologic Test for Brain Dysfunction after Brain Injury

2017 ◽  
Vol 126 (1) ◽  
pp. 94-103 ◽  
Author(s):  
Jukka Kortelainen ◽  
Eero Väyrynen ◽  
Usko Huuskonen ◽  
Jouko Laurila ◽  
Juha Koskenkari ◽  
...  
Keyword(s):  
Cardiac Arrest ◽  
Brain Injury ◽  
Pilot Study ◽  
Slow Wave ◽  
Low Frequency ◽  
Brain Dysfunction ◽  
Wave Activity ◽  
Slow Waves ◽  
Slow Wave Activity ◽  
Neurologic Outcome

Abstract Background Slow waves (less than 1 Hz) are the most important electroencephalogram signatures of nonrapid eye movement sleep. While considered to have a substantial importance in, for example, providing conditions for single-cell rest and preventing long-term neural damage, a disturbance in this neurophysiologic phenomenon is a potential indicator of brain dysfunction. Methods Since, in healthy individuals, slow waves can be induced with anesthetics, the authors tested the possible association between hypoxic brain injury and slow-wave activity in comatose postcardiac arrest patients (n = 10) using controlled propofol exposure. The slow-wave activity was determined by calculating the low-frequency (less than 1 Hz) power of the electroencephalograms recorded approximately 48 h after cardiac arrest. To define the association between the slow waves and the potential brain injury, the patients’ neurologic recovery was then followed up for 6 months. Results In the patients with good neurologic outcome (n = 6), the low-frequency power of electroencephalogram representing the slow-wave activity was found to substantially increase (mean ± SD, 190 ± 83%) due to the administration of propofol. By contrast, the patients with poor neurologic outcome (n = 4) were unable to generate propofol-induced slow waves. Conclusions In this experimental pilot study, the comatose postcardiac arrest patients with poor neurologic outcome were unable to generate normal propofol-induced electroencephalographic slow-wave activity 48 h after cardiac arrest. The finding might offer potential for developing a pharmacologic test for prognostication of brain injury by measuring the electroencephalographic response to propofol.

Slow Wave Activity Related to Working Memory Maintenance in the N-Back Task

2016 ◽  
Vol 30 (4) ◽  
pp. 141-154 ◽  
Author(s):  
Kira Bailey ◽  
Gregory Mlynarczyk ◽  
Robert West
Keyword(s):  
Working Memory ◽  
Slow Wave ◽  
Time Course ◽  
Relevant Information ◽  
Wave Activity ◽  
Slow Wave Activity ◽  
Response Accuracy ◽  
Functional Neuroanatomy ◽  
Stimulus Interval ◽  
Back Task

Abstract. Working memory supports our ability to maintain goal-relevant information that guides cognition in the face of distraction or competing tasks. The N-back task has been widely used in cognitive neuroscience to examine the functional neuroanatomy of working memory. Fewer studies have capitalized on the temporal resolution of event-related brain potentials (ERPs) to examine the time course of neural activity in the N-back task. The primary goal of the current study was to characterize slow wave activity observed in the response-to-stimulus interval in the N-back task that may be related to maintenance of information between trials in the task. In three experiments, we examined the effects of N-back load, interference, and response accuracy on the amplitude of the P3b following stimulus onset and slow wave activity elicited in the response-to-stimulus interval. Consistent with previous research, the amplitude of the P3b decreased as N-back load increased. Slow wave activity over the frontal and posterior regions of the scalp was sensitive to N-back load and was insensitive to interference or response accuracy. Together these findings lead to the suggestion that slow wave activity observed in the response-to-stimulus interval is related to the maintenance of information between trials in the 1-back task.

scholarly journals Introduction of the Abbreviated Westmead Post-Traumatic Amnesia Scale and Impact on Length of Stay

2017 ◽  
Vol 106 (4) ◽  
pp. 356-360 ◽  
Author(s):  
C. E. Watson ◽  
E. A. Clous ◽  
M. Jaeger ◽  
S. K. D’Amours
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Length Of Stay ◽  
Mild Traumatic Brain Injury ◽  
Brain Injuries ◽  
Hospital Admissions ◽  
Assessment Tool ◽  
Hospital Length Of Stay ◽  
Traumatic Amnesia ◽  
Post Traumatic

Background and Aims: Mild traumatic brain injury is a common presentation to Emergency Departments. Early identification of patients with cognitive deficits and provision of discharge advice are important. The Abbreviated Westmead Post-traumatic Amnesia Scale provides an early and efficient assessment of post-traumatic amnesia for patients with mild traumatic brain injuries, compared with the previously used assessment, the Modified Oxford Post-traumatic Scale. Material and Methods: This retrospective cohort study reviewed 270 patients with mild traumatic brain injury assessed for post-traumatic amnesia over a 2-year period between February 2011 and February 2013. It identified those assessed with Abbreviated Westmead Post-traumatic Amnesia Scale versus Modified Oxford Post-traumatic Scale, the outcomes of these post-traumatic amnesia assessments, the hospital length of stay for patients, and their readmission rates. Results: The Abbreviated Westmead Post-traumatic Amnesia Scale was used in 91% of patient cases (and the Modified Oxford Post-traumatic Scale in 7%), and of those assessed with the Abbreviated Westmead Post-traumatic Amnesia Scale, 94% cleared post-traumatic amnesia testing within 4 h. Of those assessed with the Abbreviated Westmead Post-traumatic Amnesia Scale, 56% had a shorter length of stay than had they been assessed with the Modified Oxford Post-traumatic Scale, resulting in 295 bed-days saved. Verbal and written discharge advice was provided to those assessed for post-traumatic amnesia to assist their recovery. In all, 1% of patients were readmitted for monitoring of mild post-concussion symptoms. Conclusion: The Abbreviated Westmead Post-traumatic Amnesia Scale provides an effective and timely assessment of post-traumatic amnesia for patients presenting to the Emergency Department with mild traumatic brain injury compared with the previously used assessment tool. It helps identify patients with cognitive impairment and the need for admission and further investigation, resulting in appropriate access to care. It also results in a decreased length of stay and decreased hospital admissions, with subsequent cost savings to the hospital.

Electroencephalogram analysis of non-rapid eye movement sleep in rats

1988 ◽  
Vol 255 (1) ◽  
pp. R27-R37 ◽  
Author(s):  
L. Trachsel ◽  
I. Tobler ◽  
A. A. Borbely
Keyword(s):  
Eye Movement ◽  
Slow Wave ◽  
Power Spectra ◽  
Low Frequency ◽  
Wave Activity ◽  
Slow Wave Activity ◽  
Rapid Eye Movement ◽  
Rapid Eye Movement Sleep ◽  
Episode Duration ◽  
High Frequency Activity

Sleep states and power spectra of the electroencephalogram were determined for consecutive 4-s epochs during 24 h in rats that had been implanted with electrodes under deep pentobarbital anesthesia. The power spectra in non-rapid eye movement sleep (NREMS) showed marked trends: low-frequency activity (0.75-7.0 Hz) declined progressively throughout the 12-h light period (L) and remained low during most of the 12-h dark period (D); high-frequency activity (10.25-25.0 Hz) rose toward the end of L and reached a maximum at the beginning of D. Within a single NREMS episode (duration 0.5-5.0 min), slow-wave activity (0.75-4.0 Hz) increased progressively to a plateau level. The rise was approximated by a saturating exponential function: although the asymptote level of the function showed a prominent 24-h rhythm, the time constant remained relatively stable (approximately 40 s). After short interruptions of NREMS episodes, slow-wave activity rose more steeply than after long interruptions. The marked 24-h variation of maximum slow-wave activity within NREMS episodes may reflect the level of a homeostatic sleep process.

scholarly journals Overview of Traumatic Brain Injury Patients at a Tertiary Trauma Centre

2005 ◽  
Vol 32 (2) ◽  
pp. 186-193 ◽  
Author(s):  
Elaine de Guise ◽  
Mitra Feyz ◽  
Joanne LeBlanc ◽  
Sylvain-Luc Richard ◽  
Julie Lamoureux
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Acute Care ◽  
Scale Score ◽  
Rating Scale ◽  
Functional Independence Measure ◽  
Functional Independence ◽  
Term Care ◽  
Traumatic Amnesia ◽  
Post Traumatic

ABSTRACT:Objective:The goal of this study was to provide a general descriptive and cognitive portrait of a population with traumatic brain injury (TBI) at the time of their acute care stay.Material and methods:Three hundred and forty-eight TBI patients were assessed. The following data were collected for each patient: age, level of education, duration of post-traumatic amnesia, Galveston Orientation Amnesia Test score, Glasgow Coma Scale score, results of cerebral imaging, Neurobehavioral Rating Scale score, the Functional Independence Measure cognitive score and the Glasgow Outcome Scale score.Results:The clinical profile of the population revealed a mean age of 40.2 (±18.7) and a mean of 11.5 (±3.6) years of education. Most patients presented with frontal (57.6%) and temporal (40%) lesions. Sixty-two percent had post-traumatic amnesia of less than 24 hours. Seventy percent presented with mild TBI, 14% with moderate and 15% with severe TBI. The cognitive deficits most frequently observed on the Neurobehavioral Rating Scale were in the areas of attention, memory and mental flexibility as well as slowness and mental fatigability. Most patients had good cognitive outcome on the Functional Independence Measure and scores of 2 and 3 were frequent on the GOS. Forty-five percent of the patients returned home after discharge, 51.7% were referred to in or out patient rehabilitation and 3.2% were transferred to long-term care facilities.Conclusion:Because of the specialized mandate of acute care institutions, the information provided here concerning characteristics of our TBI population is essential for more efficient decision-making and planning/programming with regards to care and service delivery.

Is Post Traumatic Amnesia any Different from Delirium?

2012 ◽  
Vol 2 (2) ◽  
pp. 82-85
Author(s):  
Samit Roy
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Behavioral Changes ◽  
Traumatic Amnesia ◽  
Post Traumatic ◽  
Narrative Account

This invited commentary discusses David W. Smith’s narrative account of his experiences during recovery from his traumatic brain injury (Smith, 2012). The author discusses the available literature around recovery from an ‘injured cognition state’ with particular reference to post traumatic amnesia, delirium, and other behavioral changes associated with recovery from traumatic brain injury.

Sensitivity of the RBANS to acute traumatic brain injury and length of post-traumatic amnesia

Brain Injury ◽  
2013 ◽  
Vol 27 (6) ◽  
pp. 689-695 ◽  
Author(s):  
Sara M. Lippa ◽  
Samuel Hawes ◽  
Emily Jokic ◽  
Jerome S. Caroselli
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Traumatic Amnesia ◽  
Acute Traumatic Brain Injury ◽  
Post Traumatic
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