Down Syndrome Abstract
of the Month:
April 1999
Cholinergic therapy for Down's syndrome.
Kishnani PS et al.
Lancet 353: 1064, 1999
Duke University Medical Center,Durham, NC, USA.
Summary:
Background:One of the changes noted in adults with Down syndrome as they age is the loss of certains neurons in the brain; specifically, those using the neurotransmitter acetylcholine. These are called cholinergic neurons. The acetylcholine is secreted from one neuron into the space between it and one or more other neurons. In this manner, the acetylcholine gives a message to the surrounding neurons to either fire or not to fire.
Cholinergic deficits have been linked to cognitive difficulties such as memory loss. This same phenomemon is seen in Alzheimer's disease. Donepezil (Aricept) is a drug classified as an acetylcholinesterase inhibitor. What that means is that donepezil keeps the body from degrading the secreted acetylcholine, leaving it around in the synapse for increased neurologic activity. Donepezil was approved by the US FDA in 1998 for the treatment of cognitive impairment of Alzheimer's disease. The Duke researchers speculated that since the neuroanatomic changes of Down syndrome are similar to Alzheimer's, donepezil might help in adults with Down syndrome also.
The study:
Four adults with Down syndrome ages 24, 27, 38 and 64 were given donepezil. The two older patients met the clinical definition of having dementia. The drug was given for 6 months, with no significant side effects seen. The results were assessed using the Vineland Adaptive Behavior Scales. At the end of 6 months, the authors report that there were "improvements in communication, expressive language, attention and mood stability." Most improvements occurred in the first 3 months of the study. Both of the older patients had improved socialization skills. No placebos were used.
My comment:
A very small study with the problems of not being a controlled or blinded study. However, that wasn't its purpose. The goal of this study was to show that some effects could be seen and that this should justify a larger, controlled, double-blinded study, and it fulfilled those goals. I understand that these researchers are going ahead with such a study. (Note: as of May 2005, the multi-center study has been completed and the researchers are still examining the data.)
If donepezil works as well as the pilot study suggests, this will be a boon for adults with DS.