MONDAY, Jan. 29 (HealthDay News) -- Neurological disorders have struck millions of people, young and old alike, in the United States, new estimates show.

Some 67 per 1,000 elderly Americans now have Alzheimer's disease, up substantially from past estimates, and nearly one out of every 1,000 people have multiple sclerosis (MS), a rate that is about 50 percent higher than earlier estimates. It's not clear if that represents improvements in diagnosis or an actual increase in incidence of MS.

The numbers form part of a review article appearing in the Jan. 30 issue of Neurology.

"These kinds of accurate numbers are needed as a basis for many different things," said Dr. Deborah Hirtz, lead author of the review and a program director for clinical trials at the National Institute of Neurological Disorders and Stroke. "Certainly, if you want to figure out the burden of disease in terms of cost and human cost, you need to have accurate numbers. If you want to look at whether the numbers are increasing, you need to have a basis to start from. If you want to plan for where research resources or health-care resources need to be spent, you need to have accurate numbers. This is just a platform for other things."

To estimate the current incidence and prevalence of 12 neurological disorders in the United States, Hirtz and her colleagues reviewed studies from nearly 500 articles published between 1990 and 2005.

When U.S. data was not available, the authors extrapolated the best available data from Western Europe.

"The paper was really not about increases or decreases," Hirtz said. "We were trying simply to look at the literature to try and get the best estimates from well-done studies. These are more accurate numbers."

Here are the other findings:

• Among the elderly, the prevalence of Parkinson disease was 9.5 per 1,000 people, which essentially corresponded with earlier numbers.
• Some 4.5 per 100,000 Americans have a new-onset spinal cord injury each year. There's not enough research to determine if this is an increase or not over previous rates, however.
• Nearly four out of every 100,000 Americans have Lou Gehrig's disease (ALS), similar to previous estimates.
• Each year, 101 of every 100,000 Americans have a traumatic brain injury, a 50 percent decrease from the past estimate. The decline probably reflects tighter hospital admission criteria, but also improvements in motor vehicle safety.
• Each year, 183 out of every 100,000 people suffer a stroke and one in 100 has had a stroke in the past. Deaths from stroke have decreased, but there appears to be an increase in incidence.
• Nearly five out of every 100,000 Americans suffer a spinal cord injury each year.
• For migraines, the prevalence is 121 out of 1,000, similar to previous estimates.
• Slightly more than seven per 1,000 people have epilepsy. Again, this was similar to previous estimates.
• Nearly six out of every 1,000 children have autism, an estimate larger than previously reported.
• Slightly more than two out of every 1,000 children have cerebral palsy.
• There wasn't enough data to give an estimate for Tourette syndrome.

More information

The National Institute of Neurological Disorders and Stroke has more on different neurological conditions.