ABSTRACT
Chronic Carbon Monoxide Poisoning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 498 23.1.4 Published Chronic Carbon Monoxide Studies Utilizing
Neuropsychological Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 502 23.2 Helffenstein Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 506
23.2.1 Sample and Exposure Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 506 23.2.1.1 Admission Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 506 23.2.1.2 Sample Demographics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 507 23.2.1.3 Source and Location of Exposure . . . . . . . . . . . . . . . . . . . . . . . 507 23.2.1.4 Level of Carbon Monoxide Exposure . . . . . . . . . . . . . . . . . . . 507 23.2.1.5 Duration and Frequency of Exposure . . . . . . . . . . . . . . . . . . . 507 23.2.1.6 Time Since Exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 508
23.2.2 Battery Administered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 508 23.2.3 Norms Utilized . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 509 23.2.4 Symptoms Experienced by Participants During Carbon
Monoxide Exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 509 23.2.5 Persisting Symptoms Reported by Participants . . . . . . . . . . . . . . . . . . . 511
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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 513 23.2.5.2 Visual Symptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 513 23.2.5.3 Cognitive Symptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 515 23.2.5.4 Psychological / Behavioral Symptoms . . . . . . . . . . . . . . . . 515
23.2.6 Neuropsychological Testing Outcome . . . . . . . . . . . . . . . . . . . . . . . . . . . . 516 23.2.6.1 Index Scores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 516 23.2.6.2 IQ Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 518 23.2.6.3 Halstead-Reitan Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 522 23.2.6.4 Memory Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 522 23.2.6.5 Academic Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 523 23.2.6.6 Visual-Visual Perceptual Testing . . . . . . . . . . . . . . . . . . . . . . 525 23.2.6.7 Speed of Information Processing . . . . . . . . . . . . . . . . . . . . . . 527 23.2.6.8 Other Motor Skills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 528 23.2.6.9 Miscellaneous Tests of Executive Function . . . . . . . . . . . 529 23.2.6.10 Language Comprehension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 530
23.2.7 Minnesota Multiphasic Personality Inventory-2 . . . . . . . . . . . . . . . . . . 531 23.2.8 Vocational Outcome. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536 23.2.9 Summary of Findings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 538
23.3 Case Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 540 23.3.1 Patient Demographics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 540 23.3.2 Exposure Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 540 23.3.3 Educational History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 540 23.3.4 Persisting Symptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 541 23.3.5 Results from Initial Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 541 23.3.6 Neuropsychological Re-evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 542
23.3.6.1 Circumstances of Re-evaulation . . . . . . . . . . . . . . . . . . . . . . . 542 23.3.6.2 Self-reported Symptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 542 23.3.6.3 Comparison of Test Scores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 543 23.3.6.4 Results from Re-evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 543
23.3.7 Summary of Case Study. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 545 23.3.8 Takeaway Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 545
23.4 Addendum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 546 Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 547 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 548
Carbon monoxide (CO) is the most common cause of poisoning in the United States and may result in neuropathologic changes which in turn result in a wide range of cognitive, visual, affective, and neurologic sequelae. The effects of moderate to severe acute CO poisoning have been well documented in the literature. For example, Gale et al.1 utilized neuropsychological testing in addition to brain imaging techniques [i.e., Single Photon Emission Computed Tomography (SPECT),
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Magnetic Resonance Imaging (qMRI)] to identify the patient’s residual neuropsychological and neuropathological impairments. Ninety-three percent of the sample group showed cognitive impairments on neuropsychological testing, including difficulties with attention, memory, executive function, and mental processing speed. Ninety-five percent of the patients were experiencing ongoing problems with depression and anxiety. The results of the imaging studies revealed that 38% of the patients had abnormal MRI scans, 67% had abnormal SPECT scans, and 67% had abnormal qMRI findings. The qMRI technique identified hippocampal atrophy and/or diffuse cortical atrophy. The SPECT identified cerebral profusion deficits, most notably in the frontal and temporal lobes. Significant correlation was identified between the neuroimaging techniques and deficits noted on neuropsychological testing.
