Oliver Sacks, the famous neurologist/writer starts his book ‘The man who mistook his wife for a Hat’ with this description:
“Neurology’s favourite word is ‘deficit’, denoting an impairment or incapacity of neurological function: loss of speech, loss of language, loss of memory, loss of vision, loss of dexterity, loss of identity and a myriad other lacks and losses of specific functions (or faculties)”
In fact, in the language of neurology, ‘losses’ and ‘excesses’ are the mainstay of describing malfunction: both at visible bodily manifestions (morphology) as well as in hidden mechanistic manifestations (physiology). For instance in Parkinson’s disease, there is deficiency of a chemical called dopamine in certain areas of the brain, and this in turn results in the characteristic slowing of movements seen in these individuals. On the other hand, in Alzheimer’s disease, there is an excess of deposition of a certain protein in the brain, which causes all the manifestations of Alzheimer’s like memory problems, personality change etc etc.
In the realm of brain injury, the approach is to attribute loss or excess of function to an injury to the corresponding area of the brain. Since neurological functions exist in such a delicate balance of positive and negative feedback mechanisms, injury to a part of the brain will cause loss of function in modalities specific to that part of the brain, but it may also cause excess of function in other areas as a compensatory mechanism. The results of this compensatory mechanism can be helpful or unhelpful to the person suffering them.
An example of this is when an injury to the brain causes paralysis of one side of the body, the spinal cord’s control of that side of the body becomes unchecked (since the higher authority, i.e, brain, is out of order). This results in that side of the body going stiff (high tone) which can be quite challenging to manage. The unchecked stiffness in the side of the body can cause problems with joint alignment which can hinder even passive movements. For instance, in such people, the stiffness of muscles in the shoulder area can result in dislocation of the shoulder. This is an important clinical issue and needs to be kept in mind to start and maintain physiotherapy early on, to save the muscle mass and tone.
So what can be the effects of a brain injury? Since brain injury usually occurs due to an external forceful collision, the outermost layers of the brain are more susceptible to damage than the inner layers. The outermost layer of the brain is also called the cortex, and subsequently such injuries can also be called ‘cortical injuries or lesions’.
The most visible effect of a serious brain injury can be paralysis. Depending on the area of the brain involved, the paralysis can involve the complete half of the body including arm, leg, face & trunk, or it can involve just a part of the body like arm or leg etc. So an injury affecting the right hemisphere of the brain will result in paralysis on the left side of the body, and vice versa.
In most people (both right and left-handed), the left hemisphere is where their speech and language centre is located. That is why the left hemisphere is called the ‘dominant hemisphere’. Injuries to the left hemisphere can,therefore, affect speech and language functions in addition to paralysis of the right side limbs. Language disorders are important to keep in mind as they are devastating and can be very hard to treat. Also, having a hinderance with language serves as a roadblock to patient’s management as it makes it difficult to assess what other problems the patient might have, like memory, understanding, cognition, etc.
Small injuries to the frontal lobes can be insignificant and go unnoticed, but high impact injury to this area of the brain can lead to a highly disabling lack of social control. These individuals can lose their sense of ‘social inhibition and propriety’: this can range from milder cases of making inopportune, rude remarks and swearing to the extremely antisocial behaviors like urination, exposure or masturbation in public. Other effects of frontal lobe injury can be apathy, irritability, lack of initiative, poor planning, inappropriate joviality, pouting, sucking, temper tantrums, anxiety and depression etc. In short, you can think of frontal lobes as the control of your social conduct and shame, and when this control is damaged, the social conduct goes awry.
Injury to the occipital lobes at the back of the head lead to visual problems. They can result in complete blindness or defects in the visual fields.
The parietal lobes, the ones lying near the crown of the head are responsible for processing sensory information coming from the body and eyes. They control the awareness of the ‘self’, e.g: how you know your hands are open or close without looking at them. This awareness of the parts of the body in relation to each other and their position in space is called ‘proprioception’. Injuries to the parietal lobes can cause a disturbance in this orientation of the body, and can have various manifestations.
For instance, in people with injury to the right parietal lobes, a phenomenon called ‘neglect’ to the left side happens. In their brains, the left side of the world does not exist any more, so they will forget to brush the left half of their teeth, miss left side of a picture or even fail to draw left half when asked to draw a clock. It is fascinating, that if you ask them to describe the buildings in the street they grew up in, they will forget to recall the buildings on the left . However, if you ask them to approach the same place from the opposite end, they will narrate all the buildings they missed out the last time, but forget to mention the buildings now falling on the left, although they described them a while ago.
Other effects of parietal lobe lesions include strange phenomena like inability to recognize familiar objects placed in a hand, even if the sensation of the hands is normal. They can have right-left disorientation, inability to calculate, or write, or recognize familiar faces. The parietal lobe lesions are the most vague ones, and consequently, people suffering from these problems are often labelled as phony or fraudulent as their functional disability is greater than physical disability. Even some doctors fail to recognize these signs (especially in the absence of more marked manifestations like paralysis or sensory loss or language loss) and hence the patients suffer at the expense of ignorance of all those around them.
Many patients with brain injury develop seizures. The seizures result from unregulated impulses from damaged areas of the brain and they can spread to surrounding areas, causing involuntary activity in the body. They also need to be kept in mind because in most cases they can be easily controlled with right medication.
In addition to these basic problems that can result from injury to specific parts of the brain, there can also be unexplained conditions that don’t fit in any category, intelligence, compassion, positivity, for instance. All of these can be accompanied by a severely distorted sense of self esteem, resulting in depression, anxiety, aggression etc: whether it is a direct result of injury or a response to the other problems acquired. In most cases the psychological manifestations become more profound and resistant to treatment with time.
I have often wondered if the physical problems resulting from brain injury are more devastating than the psychological or personality problems? Wouldn’t it be easy to assume that losing the function of a limb, or losing language or vision would be genuinely more distressing to the patient than becoming severely depressed or aggressive? But in all honestly, and having seen patients in all categories, I can say that it is impossible to grade them: psychological and personality distortions can be more, if not equally, distressing and disabling not only for the person affected but also their family.
The model of the structure-function integration of brain, while very useful, can also mislead one to believe that the answer to all problems manifest in a person can be found in a damaged part of the brain. But in reality, a human being is more than just a sum of the constituent parts. There are factors like love, hope, confidence, will and spirituality that have the shown miraculous results in some cases, and by the same measure, the absence of these supports makes it impossible for some other people with smaller injuries to lead a productive life.
About the picture: this is the seating arrangement made out of old luggage at indianapolis international airport… the whole is greater than the sum of the parts!
Arshia. Jun 28, 2013.