Editing Delta wave (section)

==Disruptions and disorders==

Regional delta wave activity not associated with NREM sleep was first described by [[W. Grey Walter]], who studied [[cerebral hemisphere]] tumors. Disruptions in delta wave activity and slow wave sleep are seen in a wide array of disorders. In some cases there may be increases or decreases in delta wave activity, while others may manifest as disruptions in delta wave activity, such as alpha waves presenting in the EEG spectrum. Delta wave disruptions may present as a result of physiological damage, changes in nutrient metabolism, chemical alteration, or may also be idiopathic.
Disruptions in delta activity is seen in adults during states of [[Substance intoxication|intoxication]] or [[delirium]] and in those diagnosed with various neurological disorders such as [[dementia]] or [[schizophrenia]].<ref name="isbn1-58562-239-7">{{cite book |author1=Hales, Robert E. |author2=Yudofsky, Stuart C. |title=The American Psychiatric Publishing Textbook of Neuropsychiatry and Behavioral Neurosciences, Fifth Edition (American Psychiatric Press Textbook of Neuropsychiatry) |publisher=American Psychiatric Publishing, Inc |year=2007 |isbn=978-1-58562-239-9 }}</ref>

===Temporal low-voltage irregular delta wave===

Temporal low-voltage irregular delta wave activity has been commonly detected in patients with [[ischemic]] brain diseases, particularly in association with small ischemic lesions and is seen to be indicative of early-stage [[cerebrovascular]] damage.<ref>Inui, Koji, Hozumi Kawamoto, Masahiko Kawakita, Kazuhisa Wako, Hiromichi Nakashima, Masanori Kamihara, and Junichi Nomura. "Temporal Delta Wave and Ischemic Lesions on MRI." Psychiatry and Clinical Neurosciences 48.4 (1994): 891–98. Print.</ref>

===Parasomnias===

[[Parasomnias]], a category of [[sleep disorders]], are often associated with disruptions in slow wave sleep. [[Sleep walking]] and sleep talking most often occur during periods of high delta wave activity. Sleep walkers have also been shown to have more hypersynchronous delta activity (HSD) compared to total time spent in stages 2, 3, and 4 sleep relative to healthy controls. HSD refers to the presence of continuous, high-voltage (> 150 μV) delta waves seen in sleep EEGs.<ref name="ReferenceA">Pilon M; Zadra A; Joncas S et al. Hypersynchronous delta waves and somnambulism: brain topography and effect of sleep deprivation. SLEEP 2006;29(1): 77–84.</ref> Parasomnias which occur deep in NREM sleep also include [[sleep terrors]] and confusional arousals.

===Sleep deprivation===

Total sleep deprivation has been shown to increase delta wave activity during sleep recovery,<ref>Feinberg, I., T. Baker, R. Leder, and J. D. March. "Response of Delta (0-3 Hz) EEG and Eye Movement Density to a Night with 100 Minutes of Sleep." Sleep 11.5 (1988): 473–87. Print.</ref> and has also been shown to increase hypersynchronous delta activity.<ref name="ReferenceA"/>

===Parkinson's disease===

Sleep disturbances, as well as [[dementia]], are common features of [[Parkinson's disease]], and patients with this disease show disrupted brain wave activity. The drug [[Rotigotine]], developed for the treatment of Parkinson's disease, has been shown to increase delta power and slow-wave sleep.

===Schizophrenia===

People with schizophrenia have shown disrupted EEG patterns, and there is a close association of reduced delta waves during deep sleep and negative symptoms associated with schizophrenia. During slow wave sleep (stages 3 and 4), people with schizophrenia have been shown to have reduced delta wave activity, although delta waves have also been shown to be increased during waking hours in more severe forms of schizophrenia.<ref>Alfimova, M. V., & Uvarova, L. G. (2007). Changes in the EEG spectral power during perception of neutral and emotionally salient words in schizophrenic patients, their relatives and healthy individuals from general population. [Article]. Zhurnal Vysshei Nervnoi Deyatelnosti Imeni I P Pavlova, 57(4), 426-436.</ref>
A recent study has shown that the right frontal and central delta wave dominance, seen in healthy individuals, is absent in patients with schizophrenia. In addition, the negative correlation between delta wave activity and age is also not observed in those with schizophrenia.<ref>Sekimoto, M., et al., Cortical regional differences of delta waves during all-night sleep in schizophrenia, Schizophr. Res. (2010), {{doi|10.1016/j.schres.2010.11.003}}</ref>

===Diabetes and insulin resistance===

Disruptions in slow wave (delta) sleep have been shown to increase risk for development of Type II diabetes, potentially due to disruptions in the growth hormone secreted by the pituitary. In addition, hypoglycemia occurring during sleep may also disrupt delta-wave activity.<ref>Abdelkarim, T. H., Westin, T., Romaker, A., & Girish, M. (2002). Presence of delta waves in REM sleep during polysomnography as a sign of acute hypoglycemic encephalopathy. [Meeting Abstract]. Sleep, 25, 531.</ref> Low-voltage irregular delta waves, have also been found in the left temporal lobe of diabetic patients, at a rate of 56% (compared to 14% in healthy controls).<ref>Appearance of Parkinsonian Syndrome after Administration of Delta Sleep-inducing Peptide into the Rat Substantia Nigra." Biull Eksp Biol Med. 109.2 (1990): 119–21. Print.</ref><ref>Inui, K., H. Sannan, H. Ota, Y. Uji, S. Nomura, H. Kaige, I. Kitayama, and J. Nomura. "EEG Findings in Diabetic Patients with and without Retinopathy." Acta Neurologica Scandinavica 97.2 (1998): 107–09. Print.</ref>

===Fibromyalgia===

Patients with [[fibromyalgia]] often report unrefreshing sleep. A study conducted in 1975 by Moldovsky ''et al.'' showed that the delta wave activity of these patients in stages 3 and 4 sleep were often interrupted by [[alpha wave]]s. They later showed that depriving the body of delta wave sleep activity also induced [[musculoskeletal]] pain and [[Fatigue (medical)|fatigue]].<ref>Nezu, Arthur M. ., Christine Maguth. Nezu, Pamela A. . Geller, and Irving B. . Weiner. Handbook of Psychology. New York: Wiley, 2003. Print.</ref>

===Alcoholism===

Alcoholism has been shown to produce sleep with less slow wave sleep and less delta power, while increasing stage 1 and REM incidence in both men and women. In long-term alcohol abuse, the influences of alcohol on sleep architecture and reductions in delta activity have been shown to persist even after long periods of abstinence.<ref>Colrain, I. M., S. Turlington, and F. C. Baker. "Impact of Alcoholism on Sleep Architecture and EEG Power Spectra in Men and Women." Sleep. 32.10 (2009): 1341–352. Print.</ref>

===Temporal lobe epilepsy===

Slow waves, including delta waves, are associated with seizure-like activity within the brain.
[[W. Grey Walter]] was the first person to use delta waves from an [[EEG]] to locate [[brain tumors]] and lesions causing [[temporal lobe epilepsy]].<ref>Walter WG. The location of cerebral tumors by electroencephalography. Lancet 1936;2: 305–8.</ref> [[Neurofeedback]] has been suggested as a treatment for temporal lobe epilepsy, and theoretically acts to reduce inappropriate delta wave intrusion, although there has been limited clinical research in this area.<ref>{{cite web |title=Biofeedback for Epileptic Seizures; EEG Neurofeedback for Epilepsy |url=http://www.epilepsyhealth.com/biofeedback.html |archive-url=https://web.archive.org/web/20110629173350/http://www.epilepsyhealth.com/biofeedback.html |archive-date=2011-06-29 |access-date=2011-02-14 |publisher=Epilepsyhealth.com}}</ref>

===Other disorders===

Other disorders frequently associated with disrupted delta-wave activity include:
* [[Narcolepsy]]
* [[Depression (clinical)|Depression]]
* [[Anxiety]]
* [[Obsessive–compulsive disorder]]
* [[Attention deficit hyperactivity disorder]] (ADHD) and its three subtypes.<ref>EEG-defined subtypes of children with attention-deficit/hyperactivity disorder. Adam R Clarke, Robert J Barry, Rory McCarthy, Mark Selikowitz.  Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology. 1 November 2001 (volume 112 issue 11 Pages 2098-2105)</ref>
* [[Juvenile chronic arthritis]]<ref>Lopes, M.C., Guilleminault, C., Rosa, A., Passarelli, C., Roizenblatt, S., Tufik, S. Delta sleep instability in children with chronic arthritis. Brazilian Journal of Medical and Biological Research. 2008;41(10): 938–43.</ref>
*[[Postural orthostatic tachycardia syndrome]] (PoTS)<ref>{{Cite journal|last1=Bagai|first1=Kanika|last2=Peltier|first2=Amanda C.|last3=Malow|first3=Beth A.|last4=Diedrich|first4=André|last5=Shibao|first5=Cyndya A.|last6=Black|first6=Bonnie K.|last7=Paranjape|first7=Sachin Y.|last8=Orozco|first8=Carlos|last9=Biaggioni|first9=Italo|last10=Robertson|first10=David|last11=Raj|first11=Satish R.|date=2016-05-15|title=Objective Sleep Assessments in Patients with Postural Tachycardia Syndrome using Overnight Polysomnograms|journal=Journal of Clinical Sleep Medicine|volume=12|issue=5|pages=727–733|doi=10.5664/jcsm.5806|pmid=26951415|pmc=4865560|issn=1550-9389}}</ref>
*[[Ehlers–Danlos syndromes|Ehlers-Danlos Syndrome]]<ref>{{Cite journal|last1=Hakim|first1=Alan|last2=De Wandele|first2=Inge|last3=O'Callaghan|first3=Chris|last4=Pocinki|first4=Alan|last5=Rowe|first5=Peter|date=2017-02-10|title=Chronic fatigue in Ehlers-Danlos syndrome-Hypermobile type|journal=American Journal of Medical Genetics Part C: Seminars in Medical Genetics|volume=175|issue=1|pages=175–180|doi=10.1002/ajmg.c.31542|pmid=28186393 |issn=1552-4868|doi-access=free}}</ref>
*[[Angelman syndrome|Angelman Syndrome]]<ref>{{Cite journal |last1=Ostrowski |first1=Lauren M. |last2=Spencer |first2=Elizabeth R. |last3=Bird |first3=Lynne M. |last4=Thibert |first4=Ronald |last5=Komorowski |first5=Robert W. |last6=Kramer |first6=Mark A. |last7=Chu |first7=Catherine J. |date=July 2021 |title=Delta power robustly predicts cognitive function in Angelman syndrome |journal=Annals of Clinical and Translational Neurology |volume=8 |issue=7 |pages=1433–1445 |doi=10.1002/acn3.51385 |issn=2328-9503 |pmc=8283185 |pmid=34047077}}</ref>