[BobbyB]

BRAIN

Hyperintensity of the Precentral Gyral Subcortical White Matter and Hypointensity of the Precentral Gyrus on Fluid-Attenuated Inversion Recovery: Variation with Age and Implications for the Diagnosis of Amyotrophic Lateral Sclerosis
S. Ngaia, Y.M. Tanga, L. Dua and S. Stuckeya
a From the Department of Radiology, Princess Alexandra Hospital, Brisbane, Queensland, Australia

Address correspondence to Stanley Ngai, MD, Department of Radiology, Princess Alexandra Hospital, Ipswich Rd, Woolloongabba, Brisbane, Queensland 4102, Australia; e-mail: sngai01@hotmail.com

BACKGROUND AND PURPOSE: Hyperintensity of the subcortical white matter (SWM) of the precentral gyrus and hypointensity of the precentral gyrus gray matter (PGGM) on fluid-attenuated inversion recovery (FLAIR) are described as potentially useful diagnostic findings in amyotrophic lateral sclerosis (ALS). A detailed study of the prevalence of these findings in various age groups has not been described.

METHODS: One hundred twenty-two patients underwent axial FLAIR brain examinations as part of either hearing loss or tinnitus evaluation. Examinations were randomly selected to reflect an even spread through the decades from ages 15 to 78 years and were reviewed by 2 readers, blinded to patient’s age and sex, for the presence/absence of the above 2 signs. If SWM hyperintensity was present, it was graded as intense as caudate nucleus (grade 1) or insula (grade 2).

RESULTS: We identified 32 cases of grade 1 and 5 cases of grade 2 SWM hyperintensity, and 28 cases of PGGM hypointensity. Both signs showed significant Spearman correlation with increasing age (r = 0.55, P < .001 for grade 1, r = 0.45, P < .001 for grade 2 SWM hyperintensity, r = 0.45, P < .001 for PGGM hypointensity). Analysis of variance showed there was a significant difference between the different age groups (P < .001) for both signs. Grading of the SWM and PGGM signals were highly reproducible with very good interobserver agreement (r = 0.88, P < .001, and r = 0.97, P < .001, respectively).

CONCLUSION: This study suggests a statistically significant relationship between increasing age and the frequency of precentral gyrus SWM hyperintensity and PGGM hypointensity on FLAIR, and reinforces previous reports that these signs can be seen in patients who do not have ALS.

http://www.ajnr.org/cgi/content/abstract/28/2/250

[BobbyB]

Turbocharging the messenger
Dalhousie scientist offers hope for spinal cord repair
By JOHN GILLIS Health Reporter




A Dalhousie University scientist and his colleagues have discovered a "volume knob" for the brain when it tells the body to walk.

The finding reveals a new aspect of the complex neurological system that could one day improve treatment for spinal cord injuries and diseases like amyotrophic lateral sclerosis, said Dr. Robert Brownstone, a neurosurgeon and professor of anatomy and neurobiology.

It is already known that the brain relies on cells called motor neurons to translate messages like "walk" or "turn" into action.

"When we walk, our brain has better things to do than to think about which muscles to control," Dr. Brownstone said Monday. "Those motor neurons can be getting the signals, but unless the volume is turned up, they’re not going to produce movement. Essentially what we’ve found here is kind of like a volume knob within the spinal cord."

Dr. Brownstone and colleagues Gareth Miles of the University of St. Andrews, who studied in the Dal lab, and Andrew Todd and Robert Hartley of the University of Glasgow in Scotland described the system of spinal interneurons they discovered. Their findings are outlined in the journal Proceedings of the National Academy of Sciences of the United States of America.

A few interneurons in the spinal cord act to amplify signals from the brain to many motor neurons.

Mr. Miles demonstrated that when these cells in mice are activated, the electrical output from the motor neurons, telling muscles to contract in response to chemical signals from the brain, is much larger than when the cells are not activated.

Because the interneurons related to walking are located in the lower back, they’re typically unaffected by spinal cord injuries.

Many people working on repairing the spinal cord are seeking ways to grow severed nerve fibres across injury sites, Dr. Brownstone said. But the fibres need to know where to go and what to do.

He said discoveries like this one, supported by funding from the Canadian Institutes of Health Research, offer hope that re-establishing even a small connection across an injury site could be enough to get messages from the brain to the rest of the body when these amplifiers are manipulated.

Some people with spinal cord injuries experience spasms, suggesting the signal amplifiers might be set too high, Dr. Brownstone said.

Amyotrophic lateral sclerosis, or Lou Gehrig’s disease, kills motor neurons in the spinal cord, gradually robbing a person of control of their body.

"If you have fewer of them they have to work harder," Dr. Brownstone said. "Maybe we can just adjust the volume knob and make things a little easier."

The next stages of research will try to draw a more complete picture of what other actions are affected by the amplification effect of the interneurons and examine the chemical receptors on the cells to determine what drugs might be used to manipulate them, he said.

Dr. Brownstone wouldn’t speculate when such treatments might be possible for people with spinal cord injuries or neurological disease, though he said collaborations like this one, with experts in Glasgow, help speed the process.

"Progress is much quicker now than it was 10 or 15 years ago," he said. "But the last thing we want to do is move too quickly."

( jgillis@herald.ca)
http://thechronicleherald.ca/Metro/558753.html