Relationship between intelligence quotient (IQ) and cerebral metabolic rate of oxygen in patients with neurobehavioural disability after traumatic brain injury

ABSTRACT

Objective: Cerebral metabolism may play a significant role in neurobehavioural disability following traumatic brain injury (TBI). In this study, we examined the relationship between intelligence quotient (IQ) and the cerebral metabolic rate of oxygen (CMRO₂) in the lateral prefrontal cortex, which was measured by ¹⁵O-labelled gas positron emission tomography (PET), in patients with TBI.

Materials and methods: The subjects were 12 patients (eight males and four females) who suffered from neurobehavioural disability following TBI. Their mean age was 33.3 years. The cause of injury was traffic accidents in all patients and the mean period after injury was 44.8 months. These patients underwent ¹⁵O-labelled gas PET and tests using either the Wechsler Adult Intelligence Scale-Revised (WAIS-R) or the Wechsler Intelligence Scale for Children-Revised (WISC-R). Pearson’s correlation between CMRO₂ and total IQ (TIQ) was calculated.

Results: A statistically significant correlation was observed between TIQ and CMRO₂ in the right Brodmann areas (BAs) 44 and 45. The lower the WAIS score, the higher the CMRO₂ in both areas.

Conclusion: Neurological function negatively correlated with the metabolism of oxygen. It was possible that changes in brain networks increased the neuronal activity in the undamaged areas and that the increased activity compensated for the function decline.

KEYWORDS:

• traumatic brain injury
• cerebral metabolism
• intelligence quotient

Declaration of Interest statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Conflicts of interest

The authors declare no conflicts of interest.