Great strides have been made in increasing awareness and research funding for neurological conditions such as Alzheimer’s disease and Parkinson’s disease. Nonetheless, there’s a lesser-known disorder called normal pressure hydrocephalus (NPH) whose symptoms mimic these two illnesses. People with NPH develop cognitive issues, experience incontinence and often have trouble walking.

Unlike Alzheimer’s and Parkinson’s, NPH can be remedied with a simple surgery. The problem? Doctors have a hard time telling the difference between NPH and its incurable counterparts. People with NPH are often misdiagnosed with Alzheimer’s or Parkinson’s disease. An estimated 700,000 Americans have NPH, yet less than 20 percent of them receive an accurate diagnosis, according to the Hydrocephalus Association.

The Difference Between Alzheimer’s, Parkinson’s and NPH

“Alzheimer’s and NPH share dementia as a common symptom, but otherwise they’re two distinct disorders,” says Adam S. Mednick, M.D., Ph.D., author of “Normal Pressure Hydrocephalus: From Diagnosis to Treatment.”

Symptoms of NPH are caused by an abnormal buildup of cerebrospinal fluid in the cavities of the brain. Adults with NPH typically develop symptoms in their 70s, although some begin experiencing issues as early as 50 years old, according to Mednick. The later onset of symptoms is another point of similarity between NPH, Alzheimer’s and Parkinson’s. However, each of these diseases progress differently because different areas of the brain are affected.

NPH mainly affects the frontal lobes of the brain, which are responsible for making decisions, regulating behavior and processing information. Alzheimer’s, on the other hand, mainly impacts the parietal and temporal lobes, which host the mind’s language and memory-making capabilities. Because of this, urinary incontinence and gait issues are often the first signs of NPH, whereas the onset of Alzheimer’s is typically marked by memory loss and language issues.

Diagnosing NPH

Diagnosing NPH is a challenging endeavor for many medical professionals. Scientists know that a stroke, head injury, brain infection or brain bleed can contribute to the dangerous buildup of cerebrospinal fluid that causes NPH, but beyond that, not much is certain.

Mednick says misdiagnosis tends to occur when a health care provider fails to ask the right questions of the patient and their family members. “The key is a careful medical history, particularly the timing of onset of each symptom relative to one another, and thorough neurologic examination,” he explains. This examination is typically conducted by a neurologist and includes brain imaging (CT and MRI scans) and comprehensive memory testing.

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Treating NPH

Once diagnosed, NPH can often be cured with a surgery to place a shunt in the brain that will drain excess cerebrospinal fluid into the abdomen. This is where Alzheimer’s, Parkinson’s and NPH differ the most. “In effect, a shunt can be a ‘cure’ for patients with NPH, whereas medications used to treat Alzheimer’s and Parkinson’s can only minimize symptoms, not slow down the disease process or reverse it,” says Mednick.

An early diagnosis is crucial to effective treatment of NPH. If the condition progresses too far, the brain can incur lasting damage and the person’s symptoms can become too severe to benefit from shunting, says Mednick. Bottom line: if your loved one is experiencing trouble walking, remembering things or controlling their bladder, they should see a physician right away.