Primary TCA occurs when there is no inherited factor causing it. Secondary TCA develops from an inherited genetic mutation.
Primary TCA is caused by mutations in genes responsible for making proteins called tau proteins. These proteins play a role in regulating cell growth and survival, among other things. Mutations in these genes cause the cells to die off over time, eventually resulting in the death of the affected person’s brain tissue.
Secondary TCA is caused by mutations in genes responsible for making proteins called alpha-synuclein proteins. Alpha-Synuclein proteins are involved in the formation of abnormal clumps of protein called Lewy bodies. They are also found in the brains of many forms of cancer, including glioblastoma multiforme (GBM). When paired with decreased blood flow or low oxygen, these clumps are a common cause of brain damage and cell death.
While the exact cause of either primary or secondary TCA is not clear, it is known that TCA often develops alongside other medical conditions such as strokes, tumors, traumatic brain injury, multiple system atrophy (MSA), and vascular parkinsonism. In some cases there may be no immediate cause determined at all, rather the condition appears to develop spontaneously.
What Are the Symptoms of a Thalamic Atrophy?
There may be no symptoms in the early stages of a thalamic atrophy. When they do appear, the most common symptoms are problems with movement and speech. Other symptoms can include cognitive impairments like difficulty thinking, confusion, memory loss, and personality changes.
Some people may experience only minor issues with these functions while others have more serious problems that affect their everyday lives. In cases of severe thalamic atrophy, people may completely lose the ability to move or speak at all.
What Is a Thalamic Infarct?
A thalamic infarct is brain damage caused by a blockage of blood flow to part of the thalamus. This is often due to a buildup of plaque in the arteries which reduces or stops the flow of blood through that artery.
How is a thalamic infarct different from a thalamic stroke?
While a thalamic stroke is caused by an interruption in blood flow, a thalamic infarct is instead caused by a complete or partial blockage of a blood vessel. The thalamus receives blood from multiple arteries, so the effects of a single blocked artery may not necessarily cause a complete loss of blood flow to that area. If only some arteries supplying blood to the thalamus are blocked, then the effects may be limited to only part of the thalamus.
What Are the Symptoms of a Thalamic Infarct?
The symptoms of a thalamic infarct depend on which part of the thalamus is affected and how much of it is damaged by the blockage. As with most brain damage, symptoms will vary based on the location and severity of the infarct. As stated earlier, damage to the sensory areas of the thalamus can cause vision and hearing issues.
Damage to motor control centers of the thalamus can cause loss of muscle function on one side of the body. This is called hemiplegia, a condition also known as “half paralyzed”.
Severe thalamic infarcts can cause death in extreme cases.
What Is a Thalamotomy?
A thalamotomy is a surgical procedure in which part of the thalamus is destroyed in order to treat specific medical conditions. The most common targets for a thalamotomy are the parts of the thalamus that control motor skills and movement.
The goal of a thalamotomy is to reduce the symptoms of conditions like Parkinson’s disease, essential tremor, and other movement disorders.
How Is a Thalamotomy Performed?
A thalamotomy is performed by accessing the brain through the skull, then using medical instruments to destroy part of the thalamus. The exact location of the thalamus that needs to be destroyed is determined before the surgery using a combination of scans and brain mapping techniques.
The surgeon begins by making an incision in the scalp, then separating the layers of tissue until the bone of the skull is exposed. Holes are drilled into the skull, then a probe is used to widen the holes and create space for surgical equipment. The top of the skull is temporarily removed so that parts of the brain can be reached.
The surgeon will use electrical stimulation to find the area of the brain responsible for motor control. Once the correct part of the brain is identified, the surgeon will use a laser, electrodes, or a heated wire to destroy a small part of that area.
Once the procedure is done, the surgeon will use the surgical tools to put the skull back together and secure it with bolts and screws. A dressing is applied to the incision in the scalp and the patient is sent to recover.
How Successful Are Thalamotomies?
Thalamotomies are only effective in treating movement disorders if the part of the brain being treated is the cause of the disorder. For example, a thalamotomy on the part of the brain that controls motor skills will not help if the root of the problem is actually in the part of the brain that controls hormones.
A thalamotomy can successfully eliminate or reduce the symptoms of Parkinson’s disease and essential tremor in many cases.
Because a thalamotomy changes brain activity in a significant way, there are often negative effects following the procedure. Some of the most common negative effects are drowsiness, confusion, and loss of balance.
Not every patient will experience negative effects from a thalamotomy. Many patients have their life drastically improved by having their condition successfully treated.
What Are Craniotomies?
A craniotomy is a procedure in which an opening is made in the skull so that surgeons can access and treat the brain. The word craniotomy comes from the Greek word for “skull” (κρανίον – kranion) and the Greek word for “to open” (τομ- tom).
Craniotomies are also known as “cranial openings” or “brain surgeries”.
What Does a Craniotomy Entail?
A craniotomy is performed by a neurosurgeon in a hospital operating room. The patient is under general anesthesia during the procedure. A medical team stands by to perform life-saving measures if necessary.
The surgeon makes an incision in the scalp, then separates the layers of skin and tissue to reveal the bone of the skull. Holes are drilled into the skull so that medical tools andlight can pass through to shine on the brain.
Once the top of the skull is removed, the surgeon will use medical instruments to remove parts of the brain. These instruments are passed through the holes in the skull and used to whatever effect is required, then are withdrawn and moved to another hole if required.
After all incision sites have been addressed, the surgeon will use medical glue to seal up any incisions, then put the skull back together and secure it with bolts and screws.
How Successful Are Craniotomies?
The success of a craniotomy is measured by whether the condition being treated is successfully eliminated or reduced. If the patient’s symptoms are due to swelling, then removing some of the brain to reduce swelling would be successful. If a tumor is found in the brain, removing it would also be successful.
Some conditions, such as an aneurysm, cannot be completely cured with a craniotomy alone. There is always a chance that the aneurysm could re-form or there may be other conditions causing the aneurysm that need to be identified and treated.
Craniotomies are generally very safe procedures, but due to the area of the brain that is being operated on there is a risk of cerebral hemorrhage and infection. In some cases, patients will also experience personality changes following a craniotomy.
What Are Endovascular Procedures?
Endovascular procedures are a specific type of brain surgery that involves using cameras and probes that are fed into the body via needles inserted in the groin or arm. The tools are then used to perform a specific task such as attaching a coil around a blood vessel to tighten it and stop bleeding, or clipping off a clot.
What Are Some Common Endovascular Procedures?
Sources & references used in this article:
Thalamic thought disorder: on being “a bit addled” by A Chatterjee, R Yapundich, M Mennemeier, JM Mountz… – Cortex, 1997 – Elsevier
Neuroanatomy of a neurobehavioral disturbance in the left anterior thalamic infarction by Y Nishio, M Hashimoto, K Ishii, E Mori – Journal of Neurology …, 2011 – jnnp.bmj.com
Posterior thalamic hemorrhage induces “pusher syndrome” by HO Karnath, L Johannsen, D Broetz, W Küker – Neurology, 2005 – AAN Enterprises