Neuropsychological Outcome After Carbon Monoxide Exposure Following a Storm: A Case-Control Study

Bérengère Pages; Mélanie Planton; Sophie Buys; Béatrice Lemesle; Philippe Birmes; Emmanuel Joseph Barbeau; Stéphanie Maziero; Laurie Cordier; Claudine Cabot; Michèle Puel; Michèle Genestal; François Chollet; Jérémie Pariente

Disclosures

BMC Neurol. 2014;14(153)

Conclusions

We report here the first study investigating cognitive and psychiatric outcome in consecutive patients after CO poisoning during a natural disaster. Using a group comparison method, we confirmed the potential multi-domain cognitive nature of sequelae PTSD is one aspect that is also to be taken into account after that specific intoxication. In spite of the medium size effect reported in this study, patients as a group reported a lower quality of life, which may have been caused by these cognitive and psychiatric sequelae. CO poisoning during storms must therefore be dealt with adequately and clinicians should be aware of its possible consequences.

1 2 3 4 5 6

Next Section

Competing interests
The authors declare that they have no competing interests.

Authors' contributions
BP participated in the design of the study, assessed patients' neuropsychological functions and performed analysis and interpretation of data. MPlanton performed the statistical analysis and helped draft the manuscript. SB assessed patients' neuropsychological functions and performed analysis and interpretation of data. BL participated in the design of the study and helped assess patients' cognitive functions. PB met all subjects and performed their psychiatric assessment. EJB participated in the design of the study and analysis of data and was involved in drafting the manuscript. SM recruited and assessed control subjects' neuropsychological functions. LC assessed patients' neuropsychological functions and performed analysis and interpretation of data. CC participated in the design of the study. MPuel performed neurological assessment and participated in the design of study. MG participated in the design of the study. FC performed neurological assessment and participated in the design of study. JP conceived the study, performed neurological assessment and was involved in drafting the manuscript. All authors read and approved the final manuscript.

Acknowledgements
We thank Virgina Clark for the English's technical writing assistance.

Table 1. Causes of CO poisoning, initial symptoms and symptoms observed during the study
Cause of CO poisoning
Electric generator	58%
Gas heater	29%
Charcoal heater	8%
Gas water heater	5%
Initial symptoms*
Headache	82%
Dizziness	55%
Nausea	53%
Fatigue	29%
Loss of consciousness	29%
Cardiac ischemia	10%
Severe ketoacidosis	3%
Acute pulmonary edema	3%
Symptoms during study evaluation
Headache	47%
Fatigue	45%
Feeling sad	39%
Concentration difficulties	39%
Feeling apathetic	32%
Experiencing reviviscences	32%
Memory complaint	26%
Reduction of daily activities	26%
Still on sick leave	24%

*No patient presented paralysis, ventricular arrhythmia, convulsion, shock, coma, stroke or rhabdomyolysis as initial symptoms. No brain lesions assessed by CT scan was reported.

Table 2. Patients' and controls' cognitive, psychiatric and global scores
	Patients (n = 38)	Controls (n = 38)	p value	Cohen's D
Cognitive assessment
Disorientation in time and space (MEM III)
MEM III, orientation (/14)	13.76 (±0.48)	13.86 (±0.34)	0.281	-
Memory
Free recall
FCRST (sum of 3 free recall,/48)	11.21 (±2.30)	11.86 (±2.32)	0.048	0.47
FCRST (delayed free recall,/16)	13 (±2.02)	13.92 (±1.51)	0.028	0.52
Cued recall
FCSRT (sum of 3 total recall,/48)	14.63 (±1.66)	15.36 (±0.88)	0.030	0.55
FCSRT (delayed total recall,/16)	15.63 (±0.91)	15.92 (±0.35)	0.073	-
Executive functions
Processing speed
TMT A time	36.73 (±17.64)	31.13 (±12.04)	0.110	-
Stroop test (denomination time)	64.21 (±14.58)	59.05 (±8.39)	0.063	-
Stroop test (reading time)	48.31 (±10.07)	41.71 (±6.54)	0.001	0.79
Digit symbol test (/133)	67.92 (±17.80)	76.71 (±17.74)	0.034	0.49
Working memory
Letter-Number sequencing (WAIS III,/21)	9.97 (±2.56)	11.36 (±2.36)	0.016	0.57
Flexibility
TMTB time	36.73 (±17.64)	31.13 (±12.04)	0.010	0.63
TMT B-A time	54.55 (±43.57)	32.24 (±24.13)	0.008	0.64
TMT B-A Errors	0.08 (±0.68)	0.13 (±0.34)	0.685	-
Inhibition
Stroop test (interference score, time)	59.65 (±38.36)	39.86 (±21.37)	0.007	0.61
Stroop test (interference score, non-corrected errors)	0.47 (±1.51)	0.02 (±0.16)	0.013	0.59
Language
Denomination (/10)	9.95(±0.23)	9.95 (±0.23)	1.000	-
Psychiatric assessment
MNI, major depressive episode, n (%)	8 (21.05%)	0	0.003	-
MNI, manic episode, n (%)	2 (5.26%)	1 (2.63%)	0.556	-
MNI, hypomanic episode, n (%)	2 (5.26%)	0	0.152	-
MNI, post-traumatic stress disorder, n (%)	6 (15.78%)	0	0.011	-
MNI, psychotic disorders, n (%)	1 (2.63%)	0	0.314	-
MNI, antisocial personality disorder, n (%)	0	0	-	-
Global assessment
Cognitive complaints
Mc Nair score (/45)	11.56 (±7.97)	13.52 (±5.00)	0.206	-
Quality of life
MOS SF-36, Total (/135)	103.81 (±18.37)	113.42 (±9.29)	0.020	0.69

MEM III, Wechsler Memory Scale; FCRST, Free and Cued Selective Reminding Test; WAIS III, Wechsler Adult Intelligence Scale; TMT, Trail Making Test; MINI, Mini International Neuropsychiatric Interview; MOS SF-36, Medical outcome Study Short Form 36.