British doctors are describing a newly identified neurological disorder that occurs mainly in older people. It's called primary orthostatic tremor, an impressive name that perhaps makes it seem more frightening than it is.
The principal symptom is something that happens when a person stands still for a long time, on a line for a movie or at a supermarket checkout, for example. The leg muscles begin to ripple, and the person becomes increasingly unstable.
Laboratory studies show that muscle tremor is at a higher frequency than found in other tremor disorders, such as Parkinson's disease. The tremor shows up in arm muscles when people stand on all fours _ or on their head, for that matter.
All that's required to restore balance is to take a step or two. Nevertheless, some older people with the condition have been falsely labeled as having a psychiatric disorder.
The cause of primary orthostatic tremor is unknown, and doctors can't agree on whether drug treatment helps. But knowing that there is such a disorder could help people take the necessary preventive measure: Keep on moving.
Dopamine depletion may affect memory
It's a neurotransmitter, a chemical that transmits signals from one nerve cell to another. Now researchers at Yale University are saying that depletion of dopamine in the front part of the brain could explain why older people lose some short-term memory, forgetting _ for example _ whether they locked the door or where the car is parked.
The theory is based on work with monkeys, so it still requires proof that the same mechanism works in humans. But the research does open the way to a possible new therapy to slow memory loss.
Most treatments for poor memory and other attention deficits have concentrated on a different neurotransmitter, acetylcholine, because it is depleted in Alzheimer's disease. Therapy to increase the brain's supply of dopamine could be a new focus for research.
Dr. Michael Freedman is the Diane and Arthur Belfer Professor of Geriatric Medicine and Director of Geriatrics at New York University Medical Center.