Featured Research

from universities, journals, and other organizations

Hopkins Researchers Identify Neurologic Problem Associated With Motor Disorders In Huntington's Disease

Date:
February 3, 2000
Source:
Johns Hopkins Medical Institutions
Summary:
For more than a century, tremors and jerky movements have been recognized as the hallmarks of Huntington's disease (HD). Scientists have long known these motor control disturbances result from damaged brain cells. Now, researchers at Johns Hopkins think they may have identified the nervous system mechanism linked to these symptoms and the part of the brain causing them. They also found that subtle jerkiness in movements may appear in HD patients long before clinical symptoms of the disease are first seen, perhaps providingn physicians with a new diagnostic tool for early HD.

EMBARGOED FOR RELEASE UNTIL WEDNESDAY, FEBRUARY 2 AT 6 P.M., EST

For more than a century, tremors and jerky movements have been recognized as the hallmarks of Huntington's disease (HD). Scientists have long known these motor control disturbances result from damaged brain cells. Now, researchers at Johns Hopkins think they may have identified the nervous system mechanism linked to these symptoms and the part ofthe brain causing them. They also found that subtle jerkiness in movements may appear in HD patients long before clinical symptoms of the disease are first seen, perhaps providing physicians with a new diagnostic tool for early HD.

According to a study published in the February 3 issue of Nature, a dysfunction exists in HD in the way the brain monitors movement, specifically in the way it corrects small errors in movement.

"If you're reaching for a glass of water, for example, the brain uses visual and other cues to constantly provide feedback to correct for errors. If everything functions properly, you end up with a glass in your hand and no spills," explains Maurice A. Smith, a doctoral student at Johns Hopkins University's Department of Biomedical Engineering. "But with HD, something goes awry."

HD is known to attack the basal ganglia, a deep-brain cluster of nerve cells at the base of the cerebrum. "It's been a mystery exactly what this part of the brain does, but our study suggests that the basal ganglia may be involved in error correction because when it's damaged, error correction suffers," Smith says.

Huntington's disease, also known as Huntington's chorea, is an inherited condition caused by a genetic mutation in the Huntington gene that causes certain nerve cells in the cerebrum to deteriorate and die. It is a progressive degenerative disease marked by involuntary, jerky movements in the arms, neck, trunk and face. Other symptoms include a wide, prancing gait, hesitant speech and intellectual deterioration. Symptoms appear in the fourth or fifth decade of life, and then progress steadily during the succeeding 10 to 20 years. Death follows, and there are no effective treatments available.

The study, directed by Christopher Ross, M.D., Ph.D., professor of psychiatry and neuroscience at Hopkins, was conducted using patients from the Huntington Disease Center at Johns Hopkins and is funded by the National Institutes of Health's National Institute of Neurological Disorders and Stroke.

Researchers examined 11 asymptomatic patients who were known carriers of the HD gene, 16 others with symptomatic HD, 3 subjects who did not have the HD gene but who had parents with HD, and 12 other age-matched, disease-free persons. A second, similar study included six control subjects with cerebellar injuries. Researchers asked the subjects to reach quickly for targets while grasping a robotic arm. The arm continuouslymeasured the movements for jerkiness and smoothness and the ability to stay on target called "aiming." Resultswere then analyzed by a computer.

While initial aiming was not dramatically disturbed in HD patients, all HD patients and several of the asymptomatic HD gene-carrier patients made movements with unusual jerkiness as the movement progressed. These results suggest, Smith says, that HD movements often begin normally, but become jerky and irregular at some point during their course because of impaired error feedback.

"This study is very important because it gives us a marker of motor abnormalities in those with the HD mutation before they become clinically affected," Ross said. "We saw a large percentage of these patients displaying elevated jerk even when more than seven years remained until symptoms of the disease were predicted tobegin."

Smith cautions that the results of his study are not likely to lead to improved diagnosis or treatments for HD,but may lead to a better basic understanding of the disease and its manifestations. "This is really very basicresearch," he says. "But hopefully this information can give us better insights into the mechanisms of HD symptoms and the part of the brain that processes error corrections."

Ross says the results may help assess treatments for HD as they become available. "Using this test, we maybe able to track improvements with experimental treatments in HD patients before they exhibit symptoms of thedisease. This could be useful in helping speed the development and testing of treatments for HD."

Jason Brandt, Ph.D., professor of psychiatry at Hopkins, and Reza Shadmehr, Ph.D., assistant professor ofbiomedical engineering, are co-authors of the study.

--JHMI--

Media Contact:

Gary Stephenson (410)955-5384Email: gstephenson@jhmi.edu


Story Source:

The above story is based on materials provided by Johns Hopkins Medical Institutions. Note: Materials may be edited for content and length.


Cite This Page:

Johns Hopkins Medical Institutions. "Hopkins Researchers Identify Neurologic Problem Associated With Motor Disorders In Huntington's Disease." ScienceDaily. ScienceDaily, 3 February 2000. <www.sciencedaily.com/releases/2000/02/000202122435.htm>.
Johns Hopkins Medical Institutions. (2000, February 3). Hopkins Researchers Identify Neurologic Problem Associated With Motor Disorders In Huntington's Disease. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2000/02/000202122435.htm
Johns Hopkins Medical Institutions. "Hopkins Researchers Identify Neurologic Problem Associated With Motor Disorders In Huntington's Disease." ScienceDaily. www.sciencedaily.com/releases/2000/02/000202122435.htm (accessed July 31, 2014).

Share This




More Mind & Brain News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Dieting At A Young Age Might Lead To Harmful Health Habits

Dieting At A Young Age Might Lead To Harmful Health Habits

Newsy (July 30, 2014) Researchers say women who diet at a young age are at greater risk of developing harmful health habits, including eating disorders and alcohol abuse. Video provided by Newsy
Powered by NewsLook.com
It's Not Just Facebook: OKCupid Experiments With Users Too

It's Not Just Facebook: OKCupid Experiments With Users Too

Newsy (July 29, 2014) If you've been looking for love online, there's a chance somebody has been looking at how you're looking. Video provided by Newsy
Powered by NewsLook.com
How Your Face Can Leave A Good Or Bad First Impression

How Your Face Can Leave A Good Or Bad First Impression

Newsy (July 29, 2014) Researchers have found certain facial features can make us seem more attractive or trustworthy. Video provided by Newsy
Powered by NewsLook.com
Losing Sleep Leaves You Vulnerable To 'False Memories'

Losing Sleep Leaves You Vulnerable To 'False Memories'

Newsy (July 27, 2014) A new study shows sleep deprivation can make it harder for people to remember specific details of an event. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



      Save/Print:
      Share:

      Free Subscriptions


      Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

      Get Social & Mobile


      Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

      Have Feedback?


      Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
      Mobile: iPhone Android Web
      Follow: Facebook Twitter Google+
      Subscribe: RSS Feeds Email Newsletters
      Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins