More than 5.3 million Americans are living with Alzheimer's disease, and the numbers are expected to rise as the nation ages. The brain-robbing disease is the only one among the top 10 causes of deaths in the United States that cannot be prevented, cured, or even slowed by conventional medicine.

While deaths from other major causes have decreased, deaths from Alzheimer's have increased 71 percent since 2000. It's the third leading cause of death, topped only by cancer and heart disease, but it's nevertheless the most feared.

In addition to the physical and emotional toll on both patients and their families, Alzheimer's is also a costly disease. According to the Alzheimer's Association, Medicare spending for patients with Alzheimer's and other types of dementia is three times higher than for seniors without dementia, and Medicaid payments are 19 times higher.

With so much at stake, scientists are racing to zero in on the causes of Alzheimer's, and are inching toward preventing and treating the deadly disease.

The year 2015 saw important advances in the fight against Alzheimer's that you should watch for in 2016. They include:

• EPPS. Korean researchers discovered a chemical called EPPS, which is similar to the amino acid taurine and destroys the characteristic toxic amyloid plaques that build up in the brains of Alzheimer's patients. Taurine is believed to have antioxidant properties and to improve mental and physical performance, and is often added to energy drinks.

When taurine was added to the drinking water of mice that had symptoms of Alzheimer's disease, the animals' cognitive function returned to normal and amyloid plaques were cleared from their brains.

Although EPPS hasn't yet been tried on humans, researchers believe it has the ability to stop neurodegeneration. According to Mayo Clinic, up to 3,000 milligrams of taurine a day is considered safe.

• Solanezumab. The American drug company Eli Lilly announced that a drug called solanezumab slowed the rate of decline in Alzheimer's patients. In patients with mild dementia, solanezumab slowed the progression of the disease over the course of several years by 30 percent. Eli Lilly plans to investigate whether or not the drug would be even more effective if given at an earlier stage of the disease.

The drug is an antibody that appears to work by deconstructing the building blocks that form the amyloid plaques and causing them to slowly disintegrate. A phase 3 trial is due to be completed in 2016.

• Ultrasound technology. Australian researchers believe that non-invasive ultrasound can break up the brain-clogging amyloid plaques associated with Alzheimer's disease and reverse memory loss. The technique has yet to be tried on humans, but was effective when used on mice bred to develop Alzheimer's.

"We're extremely excited by this innovation of treating Alzheimer's without using drug therapeutics," said Professor Jürgen Götz. "The ultrasound waves oscillate tremendously quickly, activating microglial cells that digest and remove the amyloid plaques that destroy brain synapses.

"This treatment restored memory function to the same level of normal healthy mice," Professor Götz said.

"The word 'breakthrough' is often misused, but in this case I think this really does fundamentally change our understanding of how to treat this disease, and I foresee a great future for this approach."

• Aducanumab. Brain scans of patients treated with an experimental antibody called aducanumab showed a reduction in amyloid plaque in patients who were in the earliest stages of Alzheimer's. The phase 1b randomized, placebo-controlled trial treated patients up to 54 weeks.

In addition to a reduction in plaque, the study found a significant slowing of clinical impairment in patients with mild disease. The higher the dosage a patient was given, the greater the reduction in plaque and rate of clinical decline.

• Brain fungus. The idea that a fungus might be a cause of Alzheimer's isn't new — a contemporary of Alois Alzheimer proposed the idea in 1910, but it's been mainly ignored by modern scientists. Now, molecular biologists from the Autonomous University of Madrid studied 14 cadavers with Alzheimer's, and all 14 had fungal infections. Control brains did not contain fungi.

The infections, caused by 10 different types of fungi, were found both inside and outside of cells throughout the brain.

Do fungi cause Alzheimer's? Or is the fungi simply a response to an unhealthy body? And can anti-fungal medicines slow or reverse the disease? Currently, no one knows. To find an answer, clinical trials using anti-fungal medicines on Alzheimer's patients will need to be conducted.