IQ After Pediatric Concussion: Clinical Considerations

In this issue of Pediatrics, Ware et al¹  find that intellectual functioning is not affected as early as 3 to 18 days postconcussion and up to 3 months later. Their methodologically rigorous approach from 2 large samples accounted for factors such as socioeconomic status and has an orthopedic injury control group.

Variability in the concussion outcomes literature has in large part been due to inconsistency in study methods and rigor, including heterogeneity of the clinical sample, inclusion and choice of control groups, and variability in how the outcome of interest is defined and measured. There is considerable difference in traumatic brain injury outcomes on the basis of the nature and severity of the injury. Also important is not only whether there is a control group but its comparability. For example, it is insufficient to use an age- and sex-matched healthy cohort alone. Other considerations should include factors associated with outcome of interest, in this case intellectual ability, such as parent education, parenting practices, and environmental influences that enrich or disadvantage cognitive development.²  It is equally important to distinguish between a healthy cohort and one that has undergone an orthopedic injury, the latter of which can more accurately account for the disruptions to a young nervous system that has experienced an injury to a body part other than the brain, or personal or environmental factors that may predispose one to an injury.³ 

Anytime we reduce a complex human behavior to a single number, we must consider the operational definition of the numerical construct and the error variance associated with its measurement. Although various dimensions of intelligence have been described in the scientific literature and colloquially, the term IQ in the current context refers to a quantifiable, relative cognitive intelligence of a person. Some measures of cognitive IQ only encapsulate conceptual ability, whereas others are more comprehensive in approach and will encompass a broader range of skills such as attention span and speed of information processing. IQ scores have also been parsed into fluid versus crystallized skills, the former of which is more susceptible to injury and fluctuation by external influences, such as sleep, medication side effects, emotional status, and pain, all relevant factors in concussion. Fluid intelligence refers to one’s ability to problem solve and learn and process new information. Crystallized intelligence represents an accumulation of information over time, such as vocabulary knowledge and knowledge of facts.

The conclusions of this article address intellectual functions and it is important to distinguish this higher-level conceptual skill from other cognitive functions that may be more susceptible to a concussion, particularly in the early period postinjury. These other functions include processing abilities, such as attention/concentration, thinking/processing speed, and learning and memory. Although these cognitive findings may be secondary to the acute and subacute pathophysiology of concussion itself, more often than not in the postacute period, they are symptoms secondary to a number of other factors^4,5  such as deconditioning, persistent pain (including headaches/migraines),⁶  posttraumatic stress, poor sleep,^7,8  anxiety and/or depression, somatization,⁹  catastrophizing and/or worry, or medication side effects. Many of these can co-occur with concussion, be premorbid, or be vulnerabilities that are “unlocked” when the nervous system is burdened with a concussion.

Methodologically rigorous and well-controlled studies such as that of Ware et al provide a foundation for managing expectations in course and recovery after concussion. When patients’ presentations clearly deviate from these expectations, clinicians are encouraged to explore alternative explanations. In the case of decreased IQ, alternatives include:

1. premorbid and previously undiagnosed cognitive, intellectual, or learning disabilities;

2. interference from other symptoms (eg, pain/discomfort, fatigue, poor sleep);

3. emotional reactions (anxiety/hypervigilance, depression/withdrawal, catastrophizing thinking, fear and fear-based avoidance) that impede performance or cloud perceptions of ability; and

4. suboptimal effort on testing because of any of the above or for secondary gain (eg, opportunity to avoid a nonpreferred or challenging situation, desired attention from caregivers/adults, monetary gain in a legal suit).

Far too often, well-meaning and concerned families, family advocates (including legal advocates), and even seasoned clinicians make a crucial error when they causally link the presence of cognitive deficits to a recent or remote brain injury without considering more probable alternatives. This can lead to a misattribution or inaccurate labeling of a problem that can hinder the delivery and timeliness of effective interventions, including targeted treatments for preexisting cognitive and learning problems and mood, as well as mismanagement of symptoms leading to anxiety, fear, avoidance, and deconditioning.

Brain injuries can lead to significant morbidity, and recovery can feel like a silent disorder with pervasive consequences in the social, emotional, cognitive, academic, and athletic spheres of a young person’s life. It has been critical to understand the nuances of cognition-based disability to validate patient experiences after a brain injury, to use accurate clinical nomenclature to describe this experience, and to provide necessary interventions and services. In school-aged children, it has been important to characterize cognitive challenges in the learning environment to qualify students for special education services so that they receive resources specific to their needs that may differ from those of students with common learning disabilities such as dyslexia or attention-deficit/hyperactivity disorder. At the same time, the cognitive profile of a student with an uncomplicated concussion, or even multiple uncomplicated concussions, differs from the above. As clinicians providing care to young patients with concussion, it is our obligation to be judicious when we listen to, measure, and contextualize cognitive problems, including IQ, after a brain injury. To this end, the following suggestions are offered to enhance concussion management in young patients:

• Consider the comorbidities or premorbidities listed above when there are subjective complaints or objective test results that show cognitive and intellectual declines. Accurately label and treat these as such. A neuropsychological or psychoeducational evaluation can be sought privately, in clinics, or through the school district as part of an individualized education plan (IEP) to help with diagnostic clarity.

• Messaging is important. Young people and their families need reassurance that their long-term academic, social, and vocational capacities are not expected to be negatively affected by a concussion that is well managed clinically. Early psychoeducation about typical cognitive symptoms and their expected course during recovery can go a long way in avoiding complications in recovery.

• Focus the treatment plan on interventions that curtail recovery times, including better quality sleep, pain management, psychoeducation, and reintegration into “normal” life, with supports as needed after a brief period of partial rest (24–48 hours) to avoid deconditioning (physical, cognitive, emotional/social), mounting make-up work, and, in turn, increased anxiety.