Memory one month after acute carbon monoxide intoxication: a prospective study

Abstract

Background: Serious delayed neuropsychological sequelae may complicate carbon monoxide intoxication. The existence of minor manifestations, especially memory disturbances, is not well documented. Aims: To study several memory functions after carbon monoxide intoxication. Methods: In a prospective study, 32 poisoned patients without risk factors for cognitive disturbances were compared to 32 paired control subjects one month after acute carbon monoxide intoxication (blood carbon monoxide concentration at least 1.0 mmol/l), who had been treated with standard conventional therapy. Psychometric tests included Buschke's verbal memory testing, verbal digit span, Corsi's visuospatial span, reaction times, Stroop's colours decoding test, and verbal fluency test. Results: (1) Memory functions in poisoned subjects were not worse than in the control group and were even better in some areas: learning, word recall, and quality of learning by Buschke's verbal memory testing. Attention was also better in the patients, in whom visual reaction time was shorter than in controls. (2) Results of several memory functions-quality of learning and immediate visual memory-were positively correlated with the initial carbon monoxide level. Conclusions: In a highly selected subset of patients devoid of risk factors for memory impairment, memory, objectively evaluated by psychometric testing, was not worse one month after carbon monoxide intoxication in patients undergoing standard treatment than in paired control subjects.

Carbon monoxide poisoning

“…Improvement in neuropsychometric testing after HBOT therapy in CO-poisoned patients often is cited as evidence for the effectiveness of HBOT. Other factors could result in neuropsychometric test improvement, however, such as motivation, practice effect due to repetition of the test, improvement of mental status overall, and metabolism of coingestants or cointoxicants [50,[139][140][141][142]. In addition, it is unknown whether neuropsychometric test abnormalities alone are associated with deleterious outcomes for patients with CO exposure.…”

“…Abnormalities found on neuropsychometric testing in CO-exposed patients may be explained partially by confounders. Patients who are acutely ill, suicidal, or depressed or have coingestion of other intoxicants may perform poorly on these tests [139][140][141][142]. In addition, these patients generally do not have a baseline for comparison [13,143].…”

Carbon Monoxide Poisoning

“…Improvement in neuropsychometric testing after HBOT in CO-poisoned patients is often cited as evidence for the effectiveness of HBOT. However, other factors could result in neuropsychometric test improvement, such as motivation, practice effect due to repetition of the test, improvement of overall mental status, and metabolism of coingestants or cointoxicants [43,[135][136][137][138]. In addition, it is unknown whether neuropsychometric test abnormalities alone are associated with deleterious outcomes for patients with CO exposure.…”

“…Abnormalities found on neuropsychometric testing in CO-exposed patients may be partially explained by confounders. Patients who are acutely ill, suicidal, depressed, or have coingestion of other intoxicants may perform poorly on these tests [135][136][137][138]. In addition, these patients generally do not have a baseline for comparison [9,139].…”

Plasma copeptin as a predictor of intoxication severity and delayed neurological sequelae in acute carbon monoxide poisoning

“…CO poisoning causes hypoxia, and thus causing tissue injuries in the brain, which is the most sensitive organ to hypoxia. The major neurologic and psychiatric manifestations of CO poisoning appears in the form of DNS in 12% to 67% of CO poisoning cases [2,15,20].…”