FROM THE EXPERT | Answers to common neurological questions
Neurology is a fascinating field that encompasses medical conditions involving the brain, spinal cord, peripheral nerves and muscles. Disease involving any of these structures can affect the way you think or feel and can significantly impact your ability to function in daily life. As a neurologist, I frequently encounter questions regarding stroke, dementia and Parkinson’s disease.
One question I am frequently asked is “What is the difference between stroke and TIA?” Stroke most commonly refers to death involving cells in the brain and is the No. 1 cause of long-term preventable disability in the United States. Eighty percent of strokes are preventable and are commonly caused by high blood pressure, obesity, high cholesterol, uncontrolled diabetes, heart attack and/or untreated sleep apnea.
Less commonly, strokes can occur as a result of genetic disorders of the blood increasing clotting risks or from congenital structural heart disorders. Based upon the location of a stroke, a person may have symptoms such as sudden dizziness, loss of vision, slurred speech, facial droop, weakness or numbness.
Millions of brain cells (neurons) die every minute without adequate blood flow. It is important to present to an emergency department as soon as possible so medication can be given through an IV to help restore blood flow, prevent further cell death and minimize permanent disability.
TIA stands for “transient ischemic attack” and refers to an episode of inadequate blood flow to part of the brain that stuns neurons and prevents them from working. However in TIA, blood flow is restored and the cells start working again and do not die whereas in stroke cells actually die.
TIA and stroke can look the same clinically. Studies have shown that even people who have brief stroke-like symptoms consistent with TIA actually have had a small stroke. So regardless of the duration of stroke-like symptoms, a person should present for emergent medical evaluation and assessment of stroke risk factors.
Another question I am asked is “What is the difference between Alzheimer’s disease and dementia?” Dementia is a degenerative condition of the brain that results in cognitive impairment in two or more domains such as memory, language function, orientation to space, problem solving or social function.
Alzheimer’s disease is the most common neurodegenerative disorder accounting for 70% of dementias. In Alzheimer’s disease, abnormal proteins called tau and amyloid accumulate slowly in the brain and disturb normal function. Although there are rare genetic causes for Alzheimer’s disease, treatment predominantly focuses on prevention.
Risk factors for dementia include repeated head trauma, poor cardiorespiratory function, midlife obesity, atrial fibrillation, stroke, diabetes and low educational achievement. Following a Mediterranean-style diet with high intake of polyphenols (such as nuts, citrus, soy, berries, leafy vegetables, olive oil and tea) can help protect your brain from dementia. Lecanemab is a monoclonal antibody recently approved for the treatment of Alzheimer’s disease that may prevent accumulation of amyloid; however, data is still being collected and risks include possible bleeding in the brain.
A third common question posed to me is “How do you diagnose Parkinson’s disease?” Parkinson’s disease is a degenerative condition with loss of dopamine function in the brain resulting in symptoms of resting tremor, rigidity, slowness of movements and postural instability. Excluding mimics of this disease is important.
There is no clinically available blood test to confirm Parkinson’s disease. There is a nuclear SPECT scan called a DaT scan that provides information regarding dopamine function in the brain. Although this can sometimes aid in the diagnosis of Parkinson disease, the test is not definitive. Serial clinical examination by a neurologist showing positive response to dopamine medication is the best and most reliable way to diagnose the disease.