Disorders and Disruptions:
The regional delta wave activity will be related with NREM sleep and was described first by W. Grey Walter that studied the tumours in cerebral hemisphere. In certain cases, there is decrease or increase in delta wave activity and in other cases they might cause disruptions in activity of delta waves such as like alpha waves which present the EEG spectrum. The delta wave disruptions might occur due to physiological damage which causes reactions in nutrient metabolism, alteration of chemicals and might be idiopathic. The disruptions with respect to delta activity are observed in adults at time of delirium or intoxication and the people that are diagnosed with certain neurological disorders like schizophrenia or dementia.
TLID – Temporal Low-voltage Irregular Delta Waves:
Asymmetrical activity of delta waves is detected among patients having ischemic brain diseases. Apart from that, certain ischemic diseases are also totally associated with TLID and indicates the initial phase of cerebro-vascular damage.
These are related to disruptions in slow wave sleep. The sleep talking and sleep walking generally happens under periods of increased delta wave activity. The sleep walkers are generally considered to exhibit increased HSD activity (Hypersynchronous Delta Activity) which is associated with entire time spent in different stages two, three and four sleep associated to health controls. HSD are high voltage (Greater than 150 uV), continuous delta waves which are present in sleep EEGs. The Parasomnia generally happen in NREM sleep and includes confusional arousals and sleep terrors. The complete deprivation of sleep has exhibited an increase in activity of delta waves at time of sleep recovery and is also proved to enhance HSD.
The disturbances in sleep and dementia are various known features of Parkinsons disease and patients who have PD have shown disturbed activity of brain waves. The drug routine which was developed for PD has exhibited an increase in slow wave sleep and delta wave with respect to parkinsons disease. The delta waves along with peptide which is injected to nucleus Niger of rat model has observed to enhance the symptoms of Parkinsons disease.
People who suffer from schizophrenia exhibit distorted patterns under Electroencephalogram and it is related closely to decrease in delta waves while under deep sleep and other negative symptoms which are related to schizophrenia. At the slow wave sleep (from stages 3-4), the schizophrenics have proved to have decreased activity under delta waves and also increases during waking hours when the disease is in its severe form. As per a recent study, it has been proven that the right central and frontal dominance of delta waves observed in healthy individuals cannot be seen with patients suffering schizophrenia. Apart from that, there is negative association between age and delta wave activity which is not present among people who have schizophrenia.
Insulin resistance and Diabetes
The commotions in slow wave sleep have stated that there will be greater risk with creation of Type II diabetes, which is especially due to problems in growth hormone which is released by the pituitary. Along with that, hypoglycaemia which occurs at the time of sleep can also interrupt emission of delta waves. The TLID has also been observed in left portion of temporal lobe among patients suffering from diabetes at around fifty six percent as opposite to fourteen percent under healthy controls.
The patients who suffer from fibromyalgia generally state that their sleep is not refreshing. There was a study that was conducted by Moldovsky et al. during 1975 which proved that there was interruption of alpha waves among patients who were under stages 3 and 4. They later exhibited that impoverishing their body from delta wave sleep will also induce fatigue and musculoskeletal pain.
Impact of Alcoholism
The use of alcohol has proved to reduce delta power and slow wave sleep and enhance stage 1 and REM incidence among women and men. With continuous usage of alcohol, the impact of alcohol with simplifications in delta activity and sleep architecture has proved to continue even with prolonged duration of abstention.
The slow waves which include the delta waves are related to activities such as seizure inside the brain. The 1st scientist who made use of delta waves obtained through EEG for spotting the brain tumours was W. Grey Walter. It was used to spot the lesions which led to psychomotor epilepsy. The Neuro feedback was considered as a treatment method for psychomotor epilepsy and is theoretically considered to minimize the intrusion of unnecessary delta waves, though there is very less clinical research in this category.
Various other disorders
The various disorders which are generally related to activity of delta waves include,
- Obsessive-compulsive disorder
- Juvenile Chronic Arthritis
- Attention deficit hyperactivity disorder (ADHD) / Attention deficit disorder (ADD)