Parkinson's disease, smoking, certain head injuries and even normal aging can influence our sense of smell. But certain patterns of loss in the ability to identify odors seem pronounced in Alzheimer's, researchers say. CSA Images/Color Printstock Collection/Getty Images hide caption

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A Sniff Test For Alzheimer's Checks For The Ability To Identify Odors

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Jess Thom (left) and Jess Mabel Jones from Thom's show, Backstage in Biscuit Land. Thom's website says she's "changing the world, one tic at a time." James Lyndsay/Courtesy of Supporting Wall hide caption

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Most people who say they've had a concussion say they sought out medical care at the time. Science Photo Libra/Getty Images hide caption

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Poll: Nearly 1 In 4 Americans Reports Having Had A Concussion

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Electric Currents And An 'Emotional Awakening' For One Man With Autism

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An MRI scan shows Bryan Arling's brain from above. The white-looking fluid is a subdural hematoma, or a collection of blood, that pushed part of his brain away from the skull, causing headaches and slowing his decision-making. Courtesy of Dr. Ingrid Ott, Washington Radiology Associates hide caption

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Many hospitals haven't fully implemented guidelines put forth in 2010 to minimize errors in the determination of brain death. Caiaimage/Sam Edwards/Getty Images hide caption

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Researchers Find Lapses In Hospitals' Policies For Determining Brain Death

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Oliver Sacks was an author, physician and a professor of neurology at the New York University School of Medicine. Chris McGrath/Getty Images hide caption

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Oliver Sacks: A Neurologist At The 'Intersection Of Fact And Fable'

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Neurologist Dr. Oliver Sacks speaks at Columbia University in June 2009 in New York City. Sacks, a prolific author and commentator, has died at age 82. Chris McGrath/Getty Images hide caption

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Nurses Katherine Malinak and Amy Young lift Louis DeMattio, a stroke patient, out of his hospital bed using a ceiling-mounted lift at the Cleveland Clinic. Dustin Franz for NPR hide caption

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People With Brain Injuries Heal Faster If They Get Up And Get Moving

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A color-enhanced cerebral MRI showing a glioma tumor. Scott Camazine/Science Source hide caption

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Thoughts Can Fuel Some Deadly Brain Cancers

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Jonathan Keleher is one of a handful of people who have lived their entire lives without a cerebellum. Ellen Webber for NPR hide caption

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A Man's Incomplete Brain Reveals Cerebellum's Role In Thought And Emotion

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The size of the brain of a chimpanzee (right) is considerably smaller than that of a human brain. Probably multiple stretches of DNA help determine that, geneticists say. Science Photo Library/Corbis hide caption

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Just A Bit Of DNA Helps Explain Humans' Big Brains

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Bob Smithson, 79, can now hold his head upright and breathe on his own, thanks to a medication for myasthenia gravis. M. Scott Brauer for NPR hide caption

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Medicine's Subtle Art Gives A Man The Chance To Breathe Again

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