ENTRIES A–Z
Philip Winn in Dictionary of Biological Psychology, 2003
A state of deep and persistent unconsciousness; it is explicitly not a form of deep SLEEP but something pathological. Sleep, especially REM SLEEP, involves significant and widespread neural activity; coma does not. Coma is also discriminated from STUPOR, a state of extreme unconsciousness, but one from which it is possible to rouse individuals by sensory stimulation: patients in coma are not responsive to sensory stimulation. Even REFLEX activation is lost in coma, which is a significant discriminator between this and PERSISTENT VEGETATIVE STATE. Coma is caused by damage or dysfunction in the CENTRAL NERVOUS SYSTEM. These can be divided into three broad groups: the first two are defined by their relationship to the TENTORIUM, a landmark close by the CEREBELLUM: (1) subtentorial lesions —that is, any LESION in the BRAINSTEM, typically in the PONS, (2) supratentorial lesions - typically damage to the vascular system in and around the MENINGES, (3) disorders of METABOLISM, such as HYPOGLYCAEMIA, which have widespread effects on brain. Coma is rated using any of a variety of neuropsychological instruments: the best-known is the GLASGOW COMA SCALE. For a discussion of the medical and legal issues raised by states such as coma, see PERSISTENT VEGETATIVE STATE.
Arthropod-borne virus encephalitis
Avindra Nath, Joseph R. Berger in Clinical Neurovirology, 2020
The incubation period has been estimated to be 3–10 days, on average 5–8 days [17]. A prodromal phase may be encountered with fever, headache, and abdominal distress [18]. In other cases, however, the onset may be explosive with high fever, impairment of consciousness, vomiting, focal weakness, and seizures. Infants may demonstrate a bulging fontanelle. Evolution of the illness is rapid; close to 70% of patients becoming stuporous or comatose within two days of hospital admission [18]. The duration of coma in cases with a favorable outcome has been found to be no more than five days. Early studies emphasized the high mortality rates, e.g., 68% in Massachusetts and severe neurologic sequelae [8]. The review of U.S. cases between 1988 and 1994 by Deresiewicz et al. revealed a mortality rate of 36% and moderate or severe disability in 35% of the survivors [18]. Although Eastern equine encephalitis accounted for only 30 cases, a total of 2% of pediatric neuroinvasive arboviral infections in the United States between 2003 and 2012, 10 of those patients died [19].
Organic acid disorders and disorders of fatty acid oxidation
Steve Hannigan in Inherited Metabolic Diseases: A Guide to 100 Conditions, 2018
Isovaleric acidaemia occurs in two forms – an acute and a chronic intermittent form. Symptoms may present at any time between the first week of life and adolescence, and afected individuals may experience vomiting, have a poor appetite and become lethargic. Infants with this disorder may have a low body temperature (hypothermia) and shake or tremble. Those afected by the disorder tend to show an aversion to foods containing protein, and they usually experience acute metabolic crises, which are most commonly triggered by an infection or overconsumption of high-protein foods. These crises are usually followed by severe acidity and the presence of organic compounds known as ketones in the blood and body tissues (ketoacidosis). In some cases, affected individuals may lapse into a coma. These episodes become less frequent as the child gets older. In some cases, if there is a deiciency causing other chemical reactions in the body to be disrupted, ammonia may accumulate in the blood (hyperammonaemia), which can lead to brain damage.
A scoping review of the nature and outcomes of extended rehabilitation programmes after very severe brain injury
Published in Brain Injury, 2018
A wide range of injury severity measures were used, reflecting the complexity of measuring severity across participants with injuries sustained through both traumatic and non-traumatic mechanisms. Where participants had sustained Traumatic brain injury (TBI), severity measures commonly included initial coma severity (GCS score), length of coma, and/or length of PTA. These measures highlighted the very severe nature of the injuries sustained by participants. GCS was reported in six studies, with participants in five studies having an initial GCS of 8 or below (40,43,44,47,55). In the remaining study, 81.9% of participants were reported to have had an initial GCS of 8 or below (45). Five studies reported on participants’ length of coma (42,44,53,55,56). The majority of these participants experienced prolonged coma duration (≥21 days), with participants in one study having experienced an average coma length of 16 weeks (53). Mean PTA duration was reported in nine studies and ranged from 23.5 days (57) to 90 weeks (53). These measures were often supplemented by a description of participant’s current level of function, either through the results of a standardised assessment or in qualitative terms. Qualitative descriptors referred to participants as having ‘significant behavioural disabilities’(56), ‘complex needs’ (50), and being ‘suited to a long-term nursing home placement’(53).
Familiar auditory sensory training in chronic traumatic brain injury: a case study
Published in Disability and Rehabilitation, 2018
Emily Galassi Sullivan, Ann Guernon, Brett Blabas, Amy A. Herrold, Theresa L.-B. Pape
More than 1.6 million Americans suffer from persistent deficits of brain injury, with a great deal of our service members incurring traumatic brain injury (TBI) during deployment [1]. An estimated 125,000 of these individuals remain permanently disabled, particularly after sustaining a severe TBI. Some survivors of severe TBI recover full consciousness quickly while others remain in states of seriously impaired consciousness (SIC) for protracted periods of time [2,3]. These states of SIC include coma, vegetative state (VS), also known as unresponsive wakefulness syndrome (UWS) [4], and the minimally conscious state (MCS). Coma is a state of unarousable consciousness with no signs of awareness demonstrated. Persons in coma may recover consciousness, which is most likely to occur between 2 and 4 weeks from time of injury, or progress to VS or MCS. The VS is characterized by preserved sleep/wake cycles, but no overt signs of awareness of self or environment. Persons in VS will present with eyes open and closed but demonstrate no command following, communication or interaction with environment [5,6]. The MCS is characterized by inconsistent behavioral evidence of self or environmental awareness including, but not limited to following simple commands, demonstrating yes/no responses regardless of accuracy or demonstration of appropriate, purposeful behavior [5,7].
A validation of the Polish version of the Coma Recovery Scale-Revised (CRSR)
Published in Brain Injury, 2018
Marek Binder, Urszula Górska, Anna Wójcik-Krzemień, Krzysztof Gociewicz
The ongoing improvement of intensive care has allowed many patients to retain their basic bodily functions after severe brain injury. While some patients do recover quickly, others progress from coma to one of the disorders of consciousness (DOC). Patients in the vegetative state (VS) reveal only reflexive responses and sleep-wake cycles, without any evidence of awareness of themselves or their surroundings. Patients in minimally conscious state (MCS) can produce fluctuating yet clearly discernible symptoms of voluntary behavior, whereas emergence from a minimally conscious state (EMCS) is marked by functional object use or consistent communication with others (1). Identifying subtle differences in basic neurobehavioral capacity—especially between VS, minimally conscious state and locked-in syndrome (LIS)—still remains a diagnostic challenge, confirmed by reports of the high misdiagnosis rate in patients with DOC (2,3). At the same time, reliable and accurate diagnosis provides a basis for appropriate decisions concerning the choice of individual rehabilitation programs. It also facilitates long-term treatment planning in intensive care units or longitudinal monitoring of patient recovery.