By Attorney Gordon Johnson
Call me at 800-992-9447
The frontal lobes are the largest part of the brain and also the last part of the brain to develop. While they clearly have some specific “frontal function”, as the frontal lobes represent the largest part of the brain, damage to the these lobes has potential to impact wide ranging aspects of cognition and behavioral. This is particularly true when such damage happens as a result of trauma as, in addition to whatever identifiable specific focal injury may occur, there will be accompanying diffuse injury that may be harder to pinpoint. The diffuse injury will effects which are much more difficult to isolate.
The frontal lobes are also particularly vulnerable to injury, not only because they are adjacent to large portions of the skull, but also because any time the brain is set in motion by a traumatic event, the frontal lobes are likely to collide with the inside of the skull. While such collisions between the brain and the skull are cushioned by the protective coatings around the brain - the dura and the arachnoid membranes – when the force exceeds a threshold tolerance, the frontal lobes are at risk. A force to the forehead, will cause a direct impact or transference of force to the frontal part of the brain. A force to the rear of the head, will cause a rebounding impact. The terms coup/contrecoup apply to such direct and rebound forces and the pathology which may occur at the site of impact and the diametrically opposite side of the brain.
Even more likely to occur than damage from direct collision impacts, is sliding injuries to the undersides of the frontal lobes, when they are forcefully dragged across the ridges of the inside of skull. Between the openings in the skull for the olfactory nerves and other structural ridges that help to keep the brain in place, the inside of the bottom of the skull poses a hazard to the undersides of the brain, when accidental forces, particularly industrial age forces, cause a rapid movement (acceleration/deceleration) of the brain. The most hazardous of those ridges are above the nose in an area called the “cribriform plate.” The area of the brain that rests on the cribriform plate is the orbital frontal lobe, that area immediately adjacent to the olfactory bulb – the place where the olfactory nerve, enters the brain, above the nose.
The other problem in assessing frontal lobe deficits is that as they do not fit within narrow cognitive categories, they are difficult to identify on neuropsychological tests. While some deficits can be measured by some neuropsychological instruments, most frontal lobe deficits relate to a person’s difficulties in dealing with the challenges of day to day life, which are very difficult to replicate in the testing environment. The process of the test itself, substitutes for many of the most troublesome deficits. Testing guides the survivor on a course of conduct. Outside of the test environment, those with frontal lobe damage often are adrift.
While not limited to these, frontal lobe injury can clearly manifest itself in the following symptoms:
This list is in no way exhaustive. As the frontal lobes make up such a large portion of the brain and contain much of what is our human “hard drives” for memory storage, focal injury to such lobes can impact a wide variety of thought, memory and behavior. Further, damage to the white matter of the frontal lobes (the neuronal connective tissue underlying the outer layers of the cerebral cortex) has even broader impact.
In our further pages, we will expand our discussion of the nature of frontal lobe deficits, starting with executive dysfunction. We will illustrate many of the principles in the following pages, with case studies from our initiative to record the voices of brain injury: TBI Voices.