Cognitive disruption

Simple, straightforward explanations of a patient s condition and the rationale for a specific course of action are generally well received. For those unable to benefit because of cognitive disruption, reassurance and expressions of empathy and concern are often therapeutic. A thorough, brief review of what is known about the patient s disorder should be communicated while dispelling common myths about his or her condition (e.g., the problem is related to a lack of moral strength). A patient s prognosis should be realistically and, to the extent possible, optimistically explained. Various treatment options should also be discussed, as noted in the section Informed C of Chapter 2. 

Use of caffeine has also been recommended to lower the threshold in patients who do not experience an adequate seizure (104,105 and 106). One report, however, found that caffeine appeared to produce neuronal damage in rats receiving ECS (107). Because adenosine may have neuroprotective effects, one postulated mechanism is the ability of methyixanthines (e.g., caffeine, theophylline) to block adenosine receptors. On a positive note, studies have not found a difference in cognitive disruption between patients receiving ECT with or without caffeine (108). Although the implications of the animal data for humans are not clear, and because shorter seizures may be effective in some patients, a conservative approach would be to augment with caffeine only when seizure duration is less than 20 seconds and response is inadequate ( 38). Alternatively, it may be appropriate to switch to BILAT electrode placement or from methohexital to etomidate when UND electrode stimulation produces inadequate seizure duration (even at maximal stimulus intensity) and response is insufficient ( 97, 98). 

Patients also develop cognitive disruption so that speech and written communication is affected, that is they may use a string of words with no rational meaning. Many schizophrenic patients describe religious experiences, such as hearing the word of God, or claim particular artistic sensitivity, for example they understand the hidden meaning of poems, novels, pictures and so on. 

The negative symptoms are features such as social withdrawal, apathy and lack of purposeful behaviour, reduction or flattening of emotional responses and development of cognitive disruption so that speech and written communication are affected. 

Lanphear BP University of Rochester, Rochester, NY Confirm that lead exposure appears to disrupt cognitive functions known to involve mesofrontal dopaminergic systems National Institute of Environmental Health Sciences... 

Studies that have focused on neuritic response to the NP rather than to presence of the plaque core itself have been more successful in finding a relationship between plaque-associated dystrophic neurites and dementia [30]. These studies suggest that plaque cores per se may only be an initiating event and that the gradual effects of the plaque core on adjacent neuronal pathway architecture may actuate the ultimate disruption of function. The timeframe over which the latter occurs, and the nature of how plaque-induced changes in synaptic connectivity ultimately affect cognition, is not known. 

Attentional or cognitive impairments have also been observed in rodent models of nicotine withdrawal. These include impaired performance of a test of sustained attention (Shoaib and Bizarro 2005), disrupted contextual fear conditioning (Davis and Gould 2007 Davis et al. 2005), disrupted operant behaviors (Vann et al. 2006), and decreased prepulse inhibition, a test of selective attention (Semenova et al. 2003). 

Muscarinic Ml receptor CHRMl Agonism May increase blood pressure, heart rate and sympathetic outflow — May be involved in the regulation of circadian rhythm. Antagonism Disruption of cognitive functions such as learning and memory. 

---