Amyotrophic Lateral Sclerosis - Mind vs. Body
In many ways, the worth and success of a man depends on the legacy he leaves behind. One of the most incredible legacies left behind by the people of our time is that of Stephen Hawking. And he did most of his work bound to a wheel chair, barely able to talk. What a mind right?
If I was to write about Stephen Hawking and his life and contributions, I would have to dedicate a whole website to it. But instead, the focus of this article is going to the affliction that Stephen Hawking battled against and won- Amyotrophic Lateral Sclerosis.
This disease first came into the limelight when American Baseball star Lou Gehrig was diagnosed with this disease in the nineteen thirties. Following that, a few years ago, this disease came to light with the famous ALS Ice Bucket Challenge. Social media was full of people dousing themselves in cold water to raise awareness for this condition, and the effort was a phenomenal success. However, while many people now know that such a disease exists, few really understand what it is or how it works. So lets get down to it.
The name Amyotrophic Lateral Sclerosis points towards the effect the disease has and the location of the problem. Amyotrophic refers to the eventual atrophy of the muscle fibers in the body. Lateral sclerosis refers to the part of the spinal cord that is commonly involved with a sclerosing pattern of damage.
So how does this disease even happen? Turns out that there are a number of factors that cause damage to the motor neurones. The most common genetic defect that is associated with ALS is a mutation in the SOD1 gene which codes for superoxide dismutase. Some studies conducted amongst NFL players show a connection between head injury and ALS. These changes are said to result in excitotoxicity which is cell death caused by very high levels of intracellular calcium. This inability to buffer intracellular calcium is also associated with improper functioning of the neurotransmitter glutamate and the glutamate receptors.
The human nervous system, broadly, has three types of neurones. Functionally they can be divided into sensory nerves, motor nerves and autonomic nerves. In ALS, the motor neurones alone are affected and this damage correlates with the clinical picture of the disease.
So essentially what happens is that the neurones shrink. Within the shrunk neurones there are aggregations of lipofuscin (a wear and tear pigment) and also ubiquitin. These aggregates are called Bunina bodies and contain a protein called Tar DNA binding protein 43 which is specific for ALS.
Bunina Bodies
Clinically, there are two types of ALS, depending on which muscles are first affected. The limb type of ALS affects the limbs first. This subtype presents with difficulty in walking, tripping and trouble in everyday tasks like writing and buttoning clothes. The bulbar type of ALS affects the ninth, tenth, eleventh and twelfth cranial nerves first. This subtype begins with difficulty in swallowing and manipulating food in the mouth. In severe cases, it may present with aspiration and choking. Both types eventually lead to respiratory paralysis and eventual death.
Remember that the peculiar feature of ALS and its effect on muscles is that it can have an upper motor neurone type of weakness and a lower motor neurone type of weakness.
Some cases of ALS also have a loss of cognition. There are reports of a change in personality traits, aggression, disinhibition and symptoms similar to frontotemporal dementia. Further studies have shown that cases which are associated with cognitive disturbances have a much worse prognosis.
Prognostically speaking, the bulbar type of ALS has a faster course of progression and a worse prognosis. The progress or worsening of this disease is measured by a score called the ALS Functional Rating Scale - Revised (ALSFRS-R) which is scored from 0 (severe disability) to 48 (normal). On average, someone with ALS will drop 0.9 per month but this rate may vary depending on numerous prognostic factors.
There is no treatment for ALS. But Riluzole is a drug that is available to try and reduce the damage. This is an anti glutaminergic drug slows the progression of the disease.
ALS marks a subset of diseases in medicine which have no permanent cure. These diseases are active areas of research aimed at pinpointing causative factors and curative treatment regimens. But more importantly, these disease serve to show us how little we know and how daunting an enemy we are up against. The story of Stephen Hawking is testament to the fact that despite such indomitable odds, the human race is capable of wonders.
My advice to other disabled people would be, concentrate on things your disability doesn't prevent you doing well, and don't regret the things it interferes with. Don't be disabled in spirit as well as physically.
-Stephen Hawking
Author: Narendran Sairam (Facebook)
Sources and citations
Brown, Robert H, et al. “Amyotrophic Lateral Sclerosis and Other Motor Neuron Diseases.” Harrison's Principles of Internal Medicine, by Larry Jameson et al., 19th ed., vol. 2, McGraw Hill, 2017.