Division of Neuropsychology

Alzheimer’s disease is a brain disorder that slowly destroys memory and thinking skills and, eventually, the ability to carry out the simplest tasks. In most people with the disease, symptoms first appear when they are in their mid-60s. Early-onset Alzheimer’s occurs between a person’s 30s and mid-60s and is very rare. Alzheimer’s disease is the most common cause of dementia among older adults.

The disease is named after Dr. Alois Alzheimer. In 1906, Dr. Alzheimer noticed changes in the brain tissue of a woman who had died of an unusual mental illness. Her symptoms included memory loss, language problems and unpredictable behavior. After she died, he examined her brain and found many abnormal clumps (now called amyloid plaques) and tangled bundles of fibers (now called neurofibrillary, or tau, tangles).

These plaques and tangles in the brain are still considered some of the main features of Alzheimer’s disease. Another feature is the loss of connections between nerve cells (neurons) in the brain. Neurons transmit messages between different parts of the brain, and from the brain to muscles and organs in the body. Many other complex brain changes are thought to play a role in Alzheimer’s, too.

This damage initially takes place in parts of the brain involved in memory, including the entorhinal cortex and hippocampus. It later affects areas in the cerebral cortex, such as those responsible for language, reasoning and social behavior. Eventually, many other areas of the brain are damaged.

A stroke is often referred to as a “brain attack.” It is a sudden interruption of continuous blood flow to the brain and is considered a medical emergency. A stroke occurs when a blood vessel in the brain becomes blocked or narrowed, or when a blood vessel bursts and spills blood into the brain. Just like a heart attack, a stroke requires immediate medical attention.

Some brain cells die because they stop getting the oxygen and nutrients needed to function. Other brain cells die because they are damaged by sudden bleeding in or around the brain. Some brain cells die quickly, but many linger in a compromised or weakened state for several hours. Stroke causes permanent brain damage over minutes to hours.

With stroke, “time is brain,” meaning that the sooner treatment begins, the better. Knowing the signs of stroke and calling 911 immediately can help save a relative, neighbor or friend. With timely treatment it is possible to save these cells and greatly reduce and reverse the damage.

Epilepsies are chronic neurological disorders in which clusters of nerve cells, or neurons, in the brain sometimes signal abnormally and cause seizures. Neurons normally generate electrical and chemical signals that act on other neurons, glands, and muscles to produce human thoughts, feelings, and actions.

During a seizure, many neurons fire (signal) at the same time—as many as 500 times per second, much faster than normal. This surge of excessive electrical activity happening at the same time causes involuntary movements, sensations, emotions, and behaviors and the temporary disturbance of normal neuronal activity may cause a loss of awareness.

Epilepsy can be considered a spectrum disorder because of its different causes, different seizure types, its ability to vary in severity and impact from person to person, and its range of coexisting conditions. There also are many different types of epilepsy, resulting from a variety of causes.

Multiple sclerosis (MS) is the most common disabling neurological disease of young adults, with symptom onset generally occurring between the ages of 20 and 40 years. It is also the most common of the inflammatory demyelinating disorders, conditions wherein the immune system attacks the cells that produce and maintain the myelin sheath — a whitish protective coating over nerves that helps with electrical nerve signaling.

Parkinson's disease (PD) is movement disorder of the nervous system that gets worse over time. As nerve cells (neurons) in parts of the brain weaken, are damaged, or die, people may begin to notice problems with movement, tremor, stiffness in the limbs or the trunk of the body, or impaired balance. As symptoms progress, people may have difficulty walking, talking or completing other simple tasks. Not everyone with one or more of these symptoms has PD, as the symptoms appear in other diseases as well.

A tumor is a mass of abnormal cells that either form into a new growth or were present as a mass at birth (congenital). Tumors can be noncancerous (benign) or cancerous (malignant) and occur when something goes wrong with genes that regulate cell growth, allowing cells to grow and divide out of control. Tumors can form anywhere in the body. Brain and spinal cord tumors form in the tissue inside the brain or spinal cord, which make up the central nervous system (CNS).

Depending on its type, a growing tumor may not cause any symptoms or can kill or displace healthy cells or disrupt their function. A tumor can move or press on sensitive tissue and block the flow of blood and other fluid, causing pain and inflammation. A tumor can also block the normal flow of activity in the brain or signaling to and from the brain. Some tumors don't cause any changes.

There are many different types of brain tumors, also known as central nervous system tumors (CNS). They’re generally differentiated by the cells that make up the tumors and where those tumors occur. Glioblastomas are the most common type of brain cancer. Other common brain tumors include meningiomas, pituitary adenomas and astrocytomas.

Autism spectrum disorders (ASD) are developmental disorders. Developmental disorders (or developmental disabilities) are a group of conditions and impairments in physical, learning, language or behavior that affect daily life. These disorders are primarily diagnosed in children, but present before the age of 22.  

ASD refers to a group of complex neurodevelopmental disorders caused by differences in the brain that affect communication and behavior. ASD is characterized by delays in the development of social and communication skills. Parents may note symptoms as early as infancy, although the typical age of onset is three years of age.

Attention-deficit/hyperactivity disorder (ADHD) is a neurobehavioral disorder marked by trouble controlling impulsive behavior, difficulty paying attention or overactivity. It is one of the most common neurodevelopmental disorders of childhood. ADHD interferes with a person's ability to stay on a task and maintain focus. The person may act without thinking or have difficulty with self-control.There are three types of ADHD: inattentive, hyperactive-impulsive and combined. Diagnosis depends on which of the following symptoms are strongest in the individual:

Predominantly inattentive presentation: It is hard for the individual to organize or finish a task, to pay attention to details, or to follow instructions or conversations. The person is easily distracted or forgets details of daily routines.

Predominantly hyperactive-impulsive presentation: The person fidgets and talks a lot. It is hard to sit still for long (e.g., for a meal or while doing homework). Smaller children may run, jump or climb constantly. The individual feels restless and has trouble with impulsivity. Someone who is impulsive may interrupt others a lot, grab things from people or speak at inappropriate times. It is hard for the person to wait their turn or listen to directions. A person with impulsiveness may have more accidents and injuries than others.

Combined presentation: Symptoms of the above two types are equally present in the person. Because symptoms can change over time, the presentation may change over time as well.

A traumatic brain injury (TBI) can be caused by a forceful bump, blow or jolt to the head or body, or from an object that pierces the skull and enters the brain. Not all blows or jolts to the head result in a TBI. Primary effects on the brain include various types of bleeding and tearing that injure nerve fibers and cause inflammation, metabolic changes and brain swelling.