Smarter before TBI, smarter after TBI? The IQ connection

cog-costI was notified of an interesting research finding via Twitter. Estimating IQ prior to a TBI appears to be good predictor of outcome on neuropsychological measures. It also appears to back up the theory of “cognitive reserve”. The researchers believe that this may help understand functional outcome and return to a better quality of life.

While there’s no date on it, I gather it may be relatively recent. In any case, I found it interesting, as I’ve done some reading on how pre-injury educational levels and IQ may affect the outcomes of TBI survivors, long-term. (Note: I’ve removed some of the text to shorten it for my purposes here. You can read the full text here (and I recommend you do):

Relationship between estimated pre-morbid IQ and neuropsychological measures of brain injured individuals in an acute rehab setting.

Authors: Mark Herceg, Kristen Bonistall, Joanna Spencer
Burke Rehabilitation Hospital, White Plains, NY, USA

OBJECTIVES: Cognitive reserve theories have been used in an attempt to explain differences in performance and outcome after neurological injury or illness. Theories sugest that higher education and IQ scores may preserve functional abilities after acquired brain injury. Greater cognitive reserve may buffer the effects of injury, regardless of severity. . . . The objective of this study was to analyze IQ scores of brain injured individuals obtained on admission to acute rehab and evaluate if they correlate to scores on brief neuropsychological measures.

METHODS: A retrospective cohort analysis of TBI patients admitted to an acute rehabilitation brain injury program and were administered the WTAR during the initial neuropsychological evaluation on admission. Testing was conducted within 3 days of admission. Patients were also administered the Montreal Cognitive Assessment (MOCA) and Mini Mental Status Examination-2 EV. Multivariate analysis was used to determine if individuals with higher IQ scores also had higher scores on the MOCA and MMSE-2EV. An analysis was also conducted to determine if a higher WTAR IQ correlated to MOCA gain on discharge.


CONCLUSIONS: Pre-morbid estimated IQ appears to be good predictor of outcome on neuropsychological measures and appears to back up the theory of cognitive reserve. This may help understand functional outcome and return to a better quality of life.

My Comments

I’ve got mixed feelings with regard to this study. On the one hand, I believe it’s positive to recognize the role that IQ can play in TBI recovery. And it’s a good thing (imho) that you can test for this post-injury — and have it be considered in the overall constellation of factors in recovery.

However, as a multiple mild TBI survivor who scores well on neuropsych evals and has an above-average IQ, I don’t always see a correlation between my IQ and my efficacy in everyday life. I’m smart enough, but I do stupid things all the time — the sorts of things I never remember doing before I fell in 2004. In fact, throughout the course of my mTBI-punctuated life (I’d had a bunch of them by the time I graduated high school), my above-average IQ was usually leveled against me as evidence that I wasn’t trying hard enough, I wasn’t applying myself, and I was basically choosing to fail at the tasks I undertook. None of that was true — now I know this, after a number of years of neuropsychological rehab. But the disconnects between my high IQ and my actual performance made both me and everyone around me absolutely crazy.

So, what about cognitive reserve? It’s is certainly an important consideration, however, even if you have a truckload of it, when you’re dealing with TBI issues, it doesn’t always survive the demands of the day. Given that there may be a considerable cognitive cost for things such as suppressing emotion (which happens all the time, when I’m having a bad day)1, multitasking2 (which happens all the time when I’m fatigued and more distractable), and sleep deprivation3 (which is a regular occurrence for many, many folks post-TBI, including myself, as well as myriad other factors that drain my already taxed resources… whatever surplus cognitive reserve I may have, thanks to my prior education and IQ, rapidly degrades.

The real toll, however, is less straightforward (and measurable) than simply not being able to “think straight” during a particularly demanding time, when I’m not getting enough sleep and I’ve got a lot of proverbial balls in the air.

It’s actually quite demotivational, to know that you test well, that your IQ is in good shape, and that compared to some, your faculties are relatively intact. Knowing all that sets up certain internal expectations that I’ll perform well, that I’ll be able to regain/maintain my desired level of functionality, and that I’m not going to get tripped up over the kinds of “stupid little things” that plague me on a daily basis.

As a matter of fact, having a sense of myself as more intelligent than your average bear, not only sets up higher expectations in terms of my daily functioning, but it also increases my frustration and level of discomfort when stupid little things happen like coordination issues, forgetting “simple” things, getting sequences out of order, and not understanding what people are saying to me.

In the vernacular, it makes me f*cking crazy that I slip up over the simplest things, thinking that I understand what someone’s emailing / saying to me… and then finding out I was completely wrong, and not only made an ass of myself, but caused others additional work that they couldn’t afford to do. It drives me nuts, that I have to ask for clarification about things that most people around me seem to get, right off the bat. And since I have always equated lack of composure with lower intelligence levels, when I get fatigued and agitated and melt down over any old insignificant thing, it’s deeply demoralizing and sometimes precedes a depressive episode.

I’m smarter than that. I’m sure of it. So,why the hell am I having such a hard time with everything? At times, it makes me doubt my abilities, my intelligence, and virtually everything I set out to undertake.  And going about your daily life with the added stress of expecting doom around every corner, is a pretty miserable way to live. And it drains even more energy and resources in the process — before the process has even begun.

What’s more, scoring well on neuropsychological tests (including IQ) complicates my treatment — and the way my healthcare providers treat me. Medical providers can be woefully lacking in their understanding of TBI complications. Especially if I’ve been in recovery for the long-term (>10 years), and I’m looking pretty functional, TBI complications are probably the last thing that enters their mind.

Also, my issues with attention, comprehension, memory, processing speed, and verbalizing seldom square with their definition of intelligence. If any of the above are lacking, there can be an instinctive assumption that the person they’re talking to has a lower level of intelligence, and their communication can become both stilted and truncated, leaving out important facts and also narrowing the window of opportunity to discuss questions I may have.

On the other hand, if you present as highly intelligent, providers may be reluctant or unwilling to slow down and/or accommodate extended questioning or needed aids. They may “fly” through their time with you, assuming that you’re going to pick up everything they’re saying and understand what to do with it. And should you ask them to slow down or write something down for you, they can become nonplussed and/or impatient and/or unhelpful, which not only impacts quality of care but also erodes the provider-patient relationship.

I have experienced all of this repeatedly with healthcare providers, who have either treated me like a blithering idiot, simply because I told that about my multiple-mTBI history and indicated that when I’m fatigued, I sometimes need things to be repeated. I have been laughed at by doctors who actively discouraged me from writing down what they were saying to me, so I could remember it later. I have also been under-served by professionals who equated fairly decent neuropsych eval scores with reliable procedural facility, and who routinely dismissed my concerns and ongoing issues as being something based more in my poor self-image, than actual logistical issues.

So, in these respects, measuring IQ may not in fact be helpful in treating TBI survivors…

With One Big Exception (wherein I believe the true value of this finding lies)

What makes this finding useful it its potential use in raising awareness with providers and patients, that everyone may have an unconscious bias towards higher functional / outcome expectations than is warranted by a patient’s actual circumstances.

The cognitive costs of dealing with the multitude of subtle functional impairments that come with a brain injury, can be absolutely debilitating. Confusion and frustration, coupled with just trying to keep your cool and keep all those juggling balls in the air, will drain anyone’s cognitive resources. And knowing that a sense of oneself as “high-IQ” can exacerbate the frustration and confusion (and subsequent cognitive drain) is a highly useful bit of information for both providers and patients.

Yes, the patient may be smart, but given their brain injury, they can expect to get tired more quickly — and when they get tired, they’re more likely to lose their cool. So, they need to take breaks and also recognize when they’re tired, so they can get some rest.

Yes, the patient may be above-average, but given the nature of their brain injury, they can expect to be a bit dizzy and uncoordinated, now and then, which will take more energy to deal with and makes it easier for them to get hurt — and possibly fall. So, they need to be extra careful.

Yes, the patient may score high by standard intelligence metrics, but their processing speed may be slower and their vision and hearing may have been affected, so asking people to slow down and/or repeat things is just good practice. That gives them an objective way to view the accommodations they need in a way that doesn’t make them look like an idiot.

Ultimately, I believe the best use of findings like this is to facilitate objectivity and non-judgmental data in post-TBI rehab education. Knowing that a smart person post-TBI can become a deeply frustrated, troubled, demoralized, and depressed person if they don’t fully understand the nature of their injury, and they interpret it as a sign that they’ve turned into the village idiot, is useful for anyone to know.


Raising that “red flag” about impending expectation-based frustrations (on both sides) can help both providers and patients more adequately prepare for rehabilitation and recovery.  It gives them a context in which to discuss the procedural and peripheral challenges that come with a brain injury, which may appear to be intelligence-related, but are really due to memory changes, sensory processing issues, physiology, fatigue, and brain agitation.

So, measuring IQ after a TBI can be helpful — but mainly when it’s used to set the stage for greater understanding about the nature and challenges of brain injury, not necessarily when it’s used as a predictor for outcomes.


1 See Richards & Gross, 1999 –, Richards & Gross, 2000 –
2 See JP Borst, NA Taatgen, 2007 –
3 See McCoy JG1, Strecker RE, 2011 –

Traumatic Brain Injury—Focus on Heterogeneity, Secondary Damage

A fascinating read I just found out about via Twitter:

From the text (emphasis is mine):

TBI Beyond Tau
Overall, few of the talks at SfN focused on tau, instead highlighting other aspects of brain damage. Michal Vascak in John Povlishock’s group at Virginia Commonwealth University, Richmond, detailed what happens to axons after brain injury. Vascak used a model of mild TBI in which a device rapidly injects a small volume of saline into a mouse brain, subjecting cells to a fluid concussion wave. This does not cause brain lesions or hemorrhages, but a diffuse, widespread axonal injury ensues as fragile neuronal connections twist and shear around the injury site. Moreover, even those axons that do not break may be affected, Vascak said. He reported that two days after injury, intact axons did not fire properly. He wondered if this might be due to changes in the axon initial segments, where action potentials are generated.

To get a closer look at those segments, Vascak used confocal microscopy to image individual uninjured axons in postmortem mouse brain two days after injury. Using specific markers to identify the ends of initial segments, he found that the distal end had shrunk by about 2 μm. Since this end triggers action potentials, the change would alter neuronal firing properties, and that in turn might affect overall network excitability, Vascak suggested. The data demonstrate that TBI can affect the properties of even intact axons.

Read the full article here: :

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