1/18. Synaesthesia: a case study of discordant monozygotic twins.We describe a study of 11-year-old twin sisters who are physically identical in appearance but who have considerably different conscious experiences. One twin appears to be a synaesthete in that she states that she has specific colour experiences (i.e. photisms) whenever she views, hears or thinks of digits. The other twin does not report such conscious experiences when viewing, hearing or thinking about digits. A genotypic analysis using eight microsatellite loci plus the gender of the twins and their parents confirmed that the twins are monozygotic. A phenotypic analysis using a modification of the Stroop task confirmed that only one twin is a synaesthete. We suggest that the discordance in synaesthesia may be due to either an epigenetic event, x chromosome inactivation, or a mutation of a synaesthesia gene.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
2/18. Out-of-body experience and autoscopy of neurological origin.During an out-of-body experience (OBE), the experient seems to be awake and to see his body and the world from a location outside the physical body. A closely related experience is autoscopy (AS), which is characterized by the experience of seeing one's body in extrapersonal space. Yet, despite great public interest and many case studies, systematic neurological studies of OBE and AS are extremely rare and, to date, no testable neuroscientific theory exists. The present study describes phenomenological, neuropsychological and neuroimaging correlates of OBE and AS in six neurological patients. We provide neurological evidence that both experiences share important central mechanisms. We show that OBE and AS are frequently associated with pathological sensations of position, movement and perceived completeness of one's own body. These include vestibular sensations (such as floating, flying, elevation and rotation), visual body-part illusions (such as the illusory shortening, transformation or movement of an extremity) and the experience of seeing one's body only partially during an OBE or AS. We also find that the patient's body position prior to the experience influences OBE and AS. Finally, in five patients, brain damage or brain dysfunction is localized to the temporo-parietal junction (TPJ). These results suggest that the complex experiences of OBE and AS represent paroxysmal disorders of body perception and cognition (or body schema). The processes of body perception and cognition, and the unconscious creation of central representation(s) of one's own body based on proprioceptive, tactile, visual and vestibular information-as well as their integration with sensory information of extrapersonal space-is a prerequisite for rapid and effective action with our surroundings. Based on our findings, we speculate that ambiguous input from these different sensory systems is an important mechanism of OBE and AS, and thus the intriguing experience of seeing one's body in a position that does not coincide with its felt position. We suggest that OBE and AS are related to a failure to integrate proprioceptive, tactile and visual information with respect to one's own body (disintegration in personal space) and by a vestibular dysfunction leading to an additional disintegration between personal (vestibular) space and extrapersonal (visual) space. We argue that both disintegrations (personal; personal-extrapersonal) are necessary for the occurrence of OBE and AS, and that they are due to a paroxysmal cerebral dysfunction of the TPJ in a state of partially and briefly impaired consciousness.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
3/18. Visual command hallucinations in a patient with pure alexia.Around 25% of patients with visual hallucinations secondary to eye disease report hallucinations of text. The hallucinated text conveys little if any meaning, typically consisting of individual letters, words, or nonsense letter strings (orthographic hallucinations). A patient is described with textual visual hallucinations of a very different linguistic content following bilateral occipito-temporal infarcts. The hallucinations consisted of grammatically correct, meaningful written sentences or phrases, often in the second person and with a threatening and command-like nature (syntacto-semantic visual hallucinations). A detailed phenomenological interview and visual psychophysical testing were undertaken. The patient showed a classical ventral occipito-temporal syndrome with achromatopsia, prosopagnosia, and associative visual agnosia. Of particular significance was the presence of pure alexia. illusions of colour induced by monochromatic gratings and a novel motion-direction illusion were also observed, both consistent with the residual capacities of the patient's spared visual cortex. The content of orthographic visual hallucinations matches the known specialisations of an area in the left posterior fusiform gyrus--the visual word form area (VWFA)--suggesting the two are related. The VWFA is unlikely to be responsible for the syntacto-semantic hallucinations described here as the patient had a pure alexic syndrome, a known consequence of VWFA lesions. Syntacto-semantic visual hallucinations may represent a separate category of textual hallucinations related to the cortical network implicated in the auditory hallucinations of schizophrenia.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
4/18. Psychological implications of admission to critical care.Admission to critical care can have far-reaching psychological effects because of the distinct environment. critical care services are being re-shaped to address long-term sequelae, including post-traumatic stress disorder, anxiety and depression. The long-term consequences of critical illness not only cost the individual, but also have implications for society, such as diminished areas of health-related quality-of-life in sleep, reduced ability to return to work and enjoy recreational activities (Audit Commission, 1999; Hayes et al, 2000). The debate around the phenomenon of intensive care unit (ICU) syndrome is discussed with reference to current thinking. After critical care, patients may experience amnesia, continued hallucinations or flashbacks, anxiety, depression, and dreams and nightmares. nursing care for patients while in the critical care environment can have a positive effect on psychological well-being. Facilitating communication, explaining care and rationalizing interventions, ensuring patients are oriented as to time and place, reassuring patients about transfer, providing patients,where possible, with information about critical care before admission and considering anxiolytic use, are all practices that have a beneficial effect on patient care. Follow-up services can help patients come to terms with their experiences of critical illness and provide the opportunity for them to access further intervention if desired. Working towards providing optimal psychological care will have a positive effect on patients' psychological recovery and may also help physical recuperation after critical care.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
5/18. Postural hallucinations? An unusual presentation of anaemia.The case of a 14 year old girl is reported, referred to child psychiatry with tearfulness and possible auditory hallucinations. Closer questioning revealed a history of low energy, sleeping excessively without refreshment, exertional dyspnoea, and poor growth. Psychologically, there was no evidence of low mood or negative cognitions despite the inexplicable tearfulness. Detailed enquiry revealed the "hallucinations" to be "whooshing" noises in her ears precipitated by standing. She was found to have a haemoglobin level of 55 g/l, attributed to a combination of poor diet and menorrhagia.Periodic, anaemic, cerebral hypoxia could be proposed to be the root of most, if not all, of the symptoms, illustrating the importance of marrying physical and psychological history taking with suitable investigations for an eminently treatable condition.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
6/18. Synaesthesia: discordant male monozygotic twins.Grapheme-color synaesthesia, a condition in which achromatic graphemes elicit vivid experiences of color is believed to be a genetically determined trait. We describe a study of 10-year-old twin brothers who are physically identical in appearance but who have considerably different conscious experiences. A phenotypic analysis that measured the consistency of grapheme-color pairings over test-retest confirmed that one twin has grapheme-color synaesthesia and the other twin does not. A genotypic analysis using sixteen microsatellite loci confirmed that the twins are monozygotic. These findings are problematic for previous suggestions that synaesthesia is an X-linked dominant trait. At the very least, the findings show that the penetrance of the genotype for synaesthesia is incomplete and that any view suggesting that synaesthesia is simply an X-linked dominant trait is therefore also incomplete and possibly even incorrect. The findings also negate a previous suggestion, based on a study of female monozygotic twins, that discordance of synaesthesia in identical twins is due to X-inactivation. In general, the findings raise serious questions regarding whether it is possible at this time to establish the genetic contribution to synaesthesia.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
7/18. dextromethorphan psychosis, dependence and physical withdrawal.As part of a synthesis of evidence regarding the abuse and addiction liability of dextromethorphan (DM), an over-the-counter cough medicine available in over 140 preparations, an uncommonly published case of dextromethorphan dependence (addiction) is described, with specific, rarely published complications. The individual was interviewed and several medical databases were also reviewed (medline, 1966-present; pubmed) for all content relating to the Keywords: dextromethorphan, abuse, dependence, cough medicine, addiction, withdrawal, psychosis. The patient evidenced history suggesting substance dependence, substance-induced psychosis and substance withdrawal in relation to DM. A literature review revealed that DM has specific serotonergic and sigma-1 opioidergic properties. dextrorphan (DOR), the active metabolite of DM, has similar properties; however, DOR is a weaker sigma opioid receptor agonist, and a stronger NMDA receptor antagonist. DM and DOR display specific biological features of addiction, and are capable of inducing specific psychiatric sequelae. A specific, reproducible toxidrome with significant psychiatric effects occurred, when DM was abused at greater than indicated doses, with more profound and potentially life-threatening effects at even higher doses. DM withdrawal appears evident. DM's active metabolite, DOR, has pharmacodynamic properties and intoxication effects similar to dissociatives, and may be more responsible for the dissociative effect that this DM abuser sought. However, it is this same metabolite that may be fraught with the potentially life-threatening psychoses and dissociative-induced accidents, as well as addiction. While DM has been hypothesized as the most commonly abused dissociative, health-care providers seem largely unaware of its toxidrome and addiction liability.- - - - - - - - - - ranking = 4keywords = physical (Clic here for more details about this article) |
8/18. Prolonged psychosis after amanita muscaria ingestion.amanita muscaria has a bright red or orange cap covered with small white plaques. It contains the isoxazole derivatives ibotenic acid, muscimol and muscazone and other toxins such as muscarine. The duration of clinical manifestations after A. muscaria ingestion does not usually exceed 24 hours; we report on a 5-day paranoid psychosis after A. muscaria ingestion. A 48-year-old man, with no previous medical history, gathered and ate mushrooms he presumed to be A. caesarea. Half an hour later he started to vomit and fell asleep. He was found comatose having a seizure-like episode. On admission four hours after ingestion he was comatose, but the remaining physical and neurological examinations were unremarkable. creatine kinase was 8.33 microkat/l. Other laboratory results and brain CT scan were normal. toxicology analysis did not find any drugs in his blood or urine. The mycologist identified A. muscaria among the remaining mushrooms. The patient was given activated charcoal. Ten hours after ingestion, he awoke and was completely orientated; 18 hours after ingestion his condition deteriorated again and he became confused and uncooperative. Afterwards paranoid psychosis with visual and auditory hallucinations appeared and persisted for five days. On the sixth day all symptoms of psychosis gradually disappeared. One year later he is not undergoing any therapy and has no symptoms of psychiatric disease. We conclude that paranoid psychosis with visual and auditory hallucinations can appear 18 hours after ingestion of A. muscaria and can last for up to five days.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
9/18. Postictal autoscopy in a patient with partial epilepsy.Autoscopy is an experience of seeing oneself in external space, viewed from within one's own physical body. It is a complex psycho-sensorial hallucinatory perception of one's own body image projected into external visual space, with epilepsy one of the common disorders reported to be associated with the experience. A survey of the literature revealed that there are few case reports of postictal autoscopic phenomena. Herein, we report a case of a patient with partial epilepsy who has experienced postictal autoscopy for nearly 30 years. Although the neurological mechanisms that cause autoscopic phenomena are not fully understood, wish-fulfilling fantasies released as a result of a shaken integrity regarding personal bodily image may contribute to the shaping of the symptoms, at least in the case of postictal autoscopy.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
10/18. Topically induced diphenhydramine toxicity.We report the case of a 2 1/2-year-old child who manifested acute anticholinergic toxicity after the applications of a topical calamine-antihistamine lotion. This mechanism of diphenhydramine toxicity is uncommon, with only a few other case reports noted in the literature. This case is also intriguing in that this child had an underlying varicella illness with fever that tended to obscure the picture. This report describes the characteristic history and physical examination pertinent to anticholinergic toxicity, varicella complication considerations, and case management.- - - - - - - - - - ranking = 1keywords = physical (Clic here for more details about this article) |
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