More AboutAlzheimer' s Disease

Scientists havedeveloped skin tests that may be used in the future to identify people withAlzheimer's

disease and mayultimately allow physicians to predict who is at risk of getting thisneurological

（神经病学的）disorder.

The only currentmeans of diagnosing the disease in a living patient is a long and expensiveseries of

tests that eliminateevery other cause of dementia.

"Since AloisAlzheimer described the disease nearly a century ago,people have been trying tofind a

way to accuratelydiagnose it in its early stages,"said Patricia Grady,acting director ofthe National Institute

of NeurologicalDisorders and Stroke in Bethesda,Maryland."This discovery,ifconfirmed,could prove a big

step forward in ourefforts to deal with and understand the disease."

Alzheimer's is thesingle greatest cause of mental deterioration in older people,affecting between2.5

million and 4million people in the United States alone.The devastating disordergradually destroys memory and

the ability tofunction,and eventually causes death. There is currently no known treatment forthe disease.

Researchersdiscovered that the skin cells of Alzheimer's patients have defects thatinterfere with their

ability to regulatethe flow of potassium in and out of the cells.The fact that the cell defectsare present in the

skin suggests thatAlzheimer's results from physiological changes throughout the body,and thatdementia may

be the firstnoticeable effect of these changes as the defects affect the cells in thebrain,scientists said.

The flow ofpotassium is especially critical in cells responsible for memory formation.Thescientists also

found two otherdefects that affect the cells' supply of calcium,another critical element.

One test developedby researches calls for growing skin cells in a laboratory culture and thentesting

them with anelectrical detector to determine if the microscopic tunnels that govern theflow of potassium are

open.Open potassiumchannels create a unique electrical signature.

A spokesman for theAlzheimer's Association said that if the validity of the diagnostic test can be

proven it would bean important development,but he cautioned that other promising tests forAlzheimer's

have beendisappointing.What is therelationship between Alzheimer's and dementia?

A.Dementia is one ofthe signs of Alzheimer's.

B.Alzheimer's is oneof the causes of dementia.

C.They are twocompletely different diseases.

D.They are similardefects of the human brain.