Multiple sclerosis, Parkinson’s disease and other neurological diseases may be far more common than most people believe, according to new estimates published on Monday.

Nearly one out of 1,000 Americans has multiple sclerosis (MS) and one out of 100 elderly Americans has Parkinson’s disease the survey found.

“Our estimate of MS prevalence is about 50 percent higher than a comprehensive review from 1982,” said Dr. Deborah Hirtz of the National Institute of Neurological Disorders and Stroke, who led the survey.

It is not clear whether the disease is actually more common or if it is being diagnosed more accurately, she said.

The new survey, published in the journal Neurology, also found the rate of Alzheimer’s disease was up substantially from past estimates, with 67 out of 1,000 Americans over the age of 65 affected.

Nearly 10 out of 1,000 older Americans have Parkinson’s disease, and four out of every 100,000 has amyotrophic lateral sclerosis (ALS), also called Lou Gehrig’s disease, the survey found.

The survey projects that the number of people with Parkinson’s disease will double from about 4.3 million people now to 9 million people worldwide over the next 25 years.

It corroborated other studies on childhood neurological disorders, finding that nearly six out of every 1,000 children has autism, and two out of every 1,000 children has cerebral palsy.

Hirtz and colleagues reviewed studies from nearly 500 medical papers published between 1990 and 2005 for their report.

They found that 101 out of every 100,000 Americans have a traumatic brain injury each year, 50 percent fewer than previous estimates.

More than 180 out of every 100,000 people suffer a stroke each year, and close to five out of every 100,000 have a new spinal cord injury each year.

Steven Albert of the Department of Behavioral and Community Health Sciences at the University of Pittsburgh said the impact of Alzheimer’s disease will be substantial as the population ages.

“Current projections of Alzheimer’s disease suggest that there will be about 10 million cases in the United States in 2050, of which 6 million are expected to have moderate or severe dementia,” Albert wrote in a commentary in the journal.

There is currently no cure and treatments only slightly delay the progression of Alzheimer’s disease. There is also no cure for MS or for Parkinson’s disease, although drugs can also delay their progression.