|The 2006 film directed by Tony Scott, produced by Jerry Bruckheimer, and co-written by Bill Marsilii and Terry Rossio. Just one example of the fascination of this deception of memory.|
After such an extreme sleep deprivation that I had during Tor des Geants symptoms of depersonalization and derealization are common, but interestingly not much has been written about the déjà vu experience in association with sleep deprivation even though it is a classical example of deralization. A good recent review about the effects of sleep deprivation is the article “Consequences of sleep deprivation” by Orzel-Gryglewska in Int J Occ Med Env Health 2010; 23: 95-114, but in that article déjà vu is not mentioned. I notice that I experienced some of the common symptoms listed as occuring after 4 to 5 nights sleep deprivation towards the end of the race, the worst of them probably the almost psychotic feeling of being chased up towards Refuge du Lac just below the last pass Col Malatra by two runners behind me. I did not experience any hallucinations or out-of-body experiences (OBE) otherwise commonly reported by ultrarunners. I have really tried to find good studies of the epidemiology of déjà vu after sleep deprivation without success. I have therefore no clue to how common it is and what the true incidence and prevalence is and of course I do not know how common it is in ultrarunning.
Nevertheless, reading articles specifically about the déjà vu experience yields some more information. A lot have been written about the déjà vu experience both in scientific literature and fiction prose and poetry (Sno et al. Art imitates life: Déjà vu experiences in prose and poetry. Br J Psychiatry 1992; 160: 511-51). The most comprehensive review articles about déjà vu are, however, ten years old by Alan S. Brown at the Southern Methodist University in the US. He published a paper entitled “A Review of the Déjà vu Experience” in Psychological Bulletin 2003; 129: 394-413 and a paper entitled “The Déjà vu Illusion” in Curr Dir Psychol Sci 2004; 13: 256-259 where most of the knowledge about déjà vu up until that day was summarized. It appears from prospective research beginning already in the early 20th century that many déjà vu experiences occur in the evenings in a state of fatigue following physical exertion (for instance studies by Heymans in 1904 and 1906 and Leeds in 1944). Quite interestingly, there are reports of frequent déjà vu experiences by soldiers going into battle (Linn 1954). Another common finding is that déjà vu experiences tend to peak among young adults and decline with age and that it is approximately 2/3 of all individuals who experience a déjà vu during their lifetime. The personal reactions to a déjà vu experience are generally positive in the form of surprise, curiosity and confusion. Strikingly, many individuals report that they know what will happened next during the déjà vu – bordering to a parapsychological phenomenon.
However, the scientific explanations to déjà vu are commonly divided into four categories: 1) dual processing explanations (two cognitive functions that are momentarily out of synchrony); 2) neurological explanations (brief dysfunction in the brain); 3) memory explanations and; 4) double-perception explanations (brief break in one’s ongoing perceptual processing). The two most prominent theories are neurological and memory and for the former speaks the fact that déjà vu is very common in temporal lobe epilepsy involving aberrant activity centered in mesiotemporal regions in brain structures belonging to a subcortical part of a limbic-temporal network in the hippocampus and basal ganglia. For the later memory explanation speaks for instance evidence that the déjà vu experience appears to be a component of adaptive human behavior based on metacognitive components of recognition memory, which both ontogenetically and evolutionary develops earlier than recall memory (Kusumi T. Human metacognition and the déjà vu phenomenon. Chapter 14 in Fujita & Itakura. Diversity of Cognition: Evolution, Development, Domestication, and Pathology. Kyoto University Press 2006).
And that is about how far I have reached in my review of previous research in the area. In summary, it is to my knowledge not known how common déjà vu experiences are during ultramarathons, adventure races or other prolonged endurance activities. It is neither known if there are predisposing factors to déjà vu besides the sleep deprivation and if the physical activity and fatigue exacerbates the effects of the sleep deprivation. The overreaching question is of the brain is affected by prolonged physical exertion and sleep deprivation during for instance an endurance race or other types of situations with extreme load and stress such as high-altitude mountain climbing or military activities. I have previously written on this blog about the article “Substantial and reversible brain gray matter reduction but no acute brain lesions in ultramarathon runners: experience from the TransEurope-FootRace Project” by Freund and colleagues in BMC Medicine 2012, 10:170 where no acute lesions were found during this prolonged exercise. Another study entitled “Changes in EEG during ultralong running” by Doppelmayr et al. in Journal of Human Performance in Extreme Environments 2012; 10: 4. Investigate the electroencephalogram changes in the brain of one individual (one of the co-authors) during a 12-, 24- and 56-hour ultramarathon without finding anything despite the commonly observed reduction in centre frequency and decreas in alpha and increase in theta power observed during sleep deprivation. Despite ultramarathons being excellent model systems there are more studies done during military training operations, reviewed in Lindsay & Dyche, Jeff "Sleep Disturbance Implications for Modern Military Operations" Journal of Human Performance in Extreme Environments 2012; 10: 2, at least with regards to cognitive function testing. I expect that we will see more studies on sleep deprivation and endurance activities performed during the next coming years and also interventional studies on the effect of substances such as caffeine and modafinil. Also, to come back to one of my favorite subjects, perhaps IL-1 blockade by drugs like anakinra (Kineret) might also have effect on the effects of sleep deprivation as IL-1 appears to be a key mediator substance also of these effects (see for instance Imeri & Opp. How (and why) the immune system makes us sleep. Nat Rev Neurosci 2009; 10: 199-210).