Dementia refers to loss of cognitive functioning severe enough to impact daily life. This occurs when brain cells stop working and die, or when neurons are impaired. Dementias impact focus, memory, and reasoning, among other faculties.
Different dementias impact different areas of the brain. This leads to unique sets of symptoms that require specific treatment and management approaches. Dementias that affect the cerebral cortex (cortical) disrupt our brain’s highest areas of functioning. Alzheimer’s disease and frontotemporal dementia are the most common in this category.
In this article, we’ll explore how these two types of dementia impact the brain, as well as their causes, symptoms, and treatment.
Gray matter is tissue filled with tightly packed nerve cells that covers the surface of your brain, sending and receiving signals from all over the body. Underneath, white matter helps to conduct these neurologic signals. The cerebral cortex is covered with the meninges, a multi-layer membrane that protects your brain and spinal cord.
The cerebral cortex contains
Here’s a brief breakdown of what the different lobes do:
- Frontal lobe: The largest lobe, it contains the prefrontal cortex, premotor cortex, and primary motor cortex. These areas of the brain are collectively responsible for high-level executive functioning, including language, emotional processing, analyzing social situations, and certain motor skills.
- Temporal lobe: Responsible for processing sound, and helping your brain retain visual memory, language comprehension, and emotions.
- Parietal lobe: Translates sensory input (from touch, taste, smell, etc.) into your visual system. This allows you to write, orient objects and people in space, and decide where to direct your gaze.
- Occipital lobe: This lobe processes visual input such as color, shape, and motion.
How does the cortex get damaged?
There are a number of reasons that the cerebral cortex’s functions could become impaired.
- trauma or injury
- autoimmune diseases
- other chronic health conditions
What impacts these have on the cerebral cortex will depend on the severity of damage, and the location of the affected area.
There are several types of dementia in general. Age is a risk factor, but dementias appear to be caused by a combination of both environment, genetics, and undetermined factors. Some forms of dementia destroy neurons in the cerebral cortex, essentially killing brain cells. Symptoms arise as this disrupts communication between your brain and other parts of your body.
Let’s overview the two most common types of dementia that cause damage to the cerebral cortex.
Alzheimer’s disease is a form of dementia that is caused by
- social behaviors
The mechanism of Alzheimer’s is a series of lesions (plaques) and tangled nerve fibers that accumulate throughout the brain, including the cerebral cortex. Over time, people with AD lose the ability to function independently.
Alzheimer’s is fatal. According to the Centers for Disease Control and Prevention (CDC), Alzheimer’s is the
In some cases, Alzheimer’s can damage the body’s ability to sleep, digest, and even keep the heart beating.
In frontotemporal dementia (FTD), sometimes referred to as Pick’s disease, neurons are destroyed primarily in the frontal and temporal lobes of the brain.
Because of the location of this damage, behavior and personality changes are often the most prominent early symptoms with this kind of dementia.
Creutzfeldt-Jakob disease (CJD)
Creutzfeldt-Jakob disease (CJD) is a rare, degenerative brain disease that leads to rapidly progressing dementia in its final stages.
CJD symptoms include sudden behavior and personality changes, vision and memory problems, insomnia, and muscle spasms. There is no cure for Creutzfeldt-Jakob disease. It is fatal, with the majority of people who develop CJD dying within a year.
Many types of dementia share cognitive and motor symptoms, but there are important differences depending on type.
Memory problems are usually the first symptoms noticed when someone has early-stage Alzheimer’s disease. This is because neurons in the entorhinal cortex and hippocampus are usually the first to be destroyed. Memory, language, and communication problems worsen over time, and eventually behavioral and emotional symptoms appear as well.
- wandering around, getting lost in familiar places
- trouble communicating
- not recognizing the faces of family or friends
- sleep disturbances
- problems with motor skills
- psychosis (disconnect from reality)
People with Alzheimer’s may eventually need around-the-clock care to assist them with daily functions, including dressing, eating, and bathing.
Frontotemporal dementia has a wide range of symptoms. As with many types of dementia, not everyone with FTD will experience every symptom.
Rather than being split into stages, the symptoms with this form of dementia are categorized by the parts and functions of the body that are affected. As you can see, FTD often manifests with a lot of physiological (bodily) symptoms, compared to Alzheimer’s.
- Behavioral variant frontotemporal dementia (bvFTD). This is the most common form of FTD. Often memory isn’t affected as much as cognitive processes are, such as planning, processing, and thinking.
- Primary progressive aphasia (PPA). This form of FTD affects communication abilities, causing slurred speech, and difficulty finding or recognizing words (aphasia).
- Movement disorders. Corticobasal syndrome and progressive supranuclear palsy can occur when FTD destroys brain cells involved in motor coordination. Symptoms can include muscle rigidly or weakness, falling, trouble swallowing, and more.
There is currently no cure for dementia, regardless of the type you have. Instead, treatments are aimed at managing individual physical, mental, or emotional symptoms.
Examples of medications used to treat elements of Alzheimer’s disease are:
- cholinesterase inhibitors like galantamine, rivastigmine, and donepezil
- immunotherapies like aducanumab
- a N-methyl D-aspartate (NMDA) antagonist like memantine
- antiseizure medications
- anti-anxiety medications
- sleep aids
Alzheimer’s management also includes providing adaptable caregiving. Caregivers may have to adjust their approach to situations in response to someone with dementia’s irritability, depression, or confusion.
- Avoid raising your voice. Speak steadily and calmly, and listen.
- Keep a regular routine, making space for quiet moments.
- Fill the living environment with familiar or favorite objects.
- Reduce any clutter, and prevent overcrowding of people in the room.
- Give the person back control whenever possible. This could mean letting them make a specific choice or decision regarding their schedule.
Frontotemporal lobe dementia
There are no medications currently FDA-approved to treat FTD. Clinical trials are underway. However, the above medications can be used to treat specific symptoms that may arise from this form of dementia, including depression and psychosis.
If a person with dementia also has Parkinson’s disease, they may be additionally treated with dopamine agonists. Other mental or physical health conditions may also require separate medications alongside dementia treatments.
Other types of dementia affect different areas of the brain, although they can share symptoms with the cortical types discussed here. Remember that dementia describes a collection of symptoms that affect our brain cells, not one specific disease.
Other types of dementias include:
Dementia symptoms and their management vary depending on the part of the brain that’s most affected. Alzheimer’s disease and frontotemporal dementia both involve the cerebral cortex, our brain’s gray matter. This means they impact higher-level brain functions, like memory and communication, and can eventually have physical symptoms.
There is no cure for dementia, and it is fatal in many cases. As more brain cells die, your body is no longer able to carry out basic functions. Many people with dementia in the moderate to late stages need full-time caregivers.
There is no cure for dementia, but your doctor can work with you to try and slow progression of the disease, or reduce the burden of your symptoms.