"Alzheimers disease now affects an estimated . million Americans and after decades of feverish work researchers have so far failed to find a treatment that halts or reverses the inexorable loss of memory function and thinking ability that characterize this feared illness. But researchers have been quite successful at devising ways to diagnose Alzheimers earlier and earlier. And that capability has emerged alongside evidence of a tantalizing possibility that if you can catch the disease early enough  ideally when symptoms of confusion or memory loss are just emerging or before  some therapies already in hand might essentially halt its progress. For anyone who detects some mental slippage and wonders Is it Alzheimers the current state of dementia research raises a very real and very wrenching dilemma If I can know do I want to know That is if its Alzheimers disease would I do anything differently Would there be some benefit in knowing for my loved ones for myself Doctors and insurers including the federal government which administers Medicare are asking some variants of the same questions If an effective test which costs between  and  a shot can diagnose dementia early and distinguish Alzheimers from other forms of dementia should it be recommended to patients with cognitive concerns and routinely covered by their insurance Would it make patients lives better or lower the cost of their care Newly unveiled research results are bringing some clarity to such deliberations. And other new research published Wednesday in the journal Neurology proposes a new diagnostic tool that may be able to detect Alzheimers and distinguish it from another form of dementia more simply and cheaply than does the best test now available. At the Alzheimers Assn. International Conference in London last week researchers reported their preliminary findings from a tria https_AAICWedbriefingDevelopingTopics.aspl  https_AAICSunPETScanRelease.aspthat is testing the impact of diagnostic testing for Alzheimers disease on nearly  Medicare beneficiaries.  All of these study participants  largely people in their s all with a diagnosis of either mild cognitive impairment or atypical dementia  are living with the unconfirmed suspicion that they have Alzheimers. The study is underwritten by the Centers for Medicare  Medicaid Services and the Alzheimers Assn. It set out to find out whether knowing  getting the costly test that would offer either confirmation or reprieve  would change the way that patients with cognitive troubles are treated or the way that they plan their lives. The preliminary results suggested it did. After getting the results of a PET brain scan to detect and measure amyloid deposits which are the key hallmark of Alzheimers disease roughly twothirds of the subjects saw their medication regimens changed or were counseled differently by their doctors about what to expect. That new information may have guided family caregivers in planning their own futures or prodded patients to make financial decisions and powerofattorney assignments sooner. Some who learned that they did not have Alzheimers discontinued medications that can have unpleasant side effects. Others learned they do have Alzheimers and decided to enroll in clinical trials that will test new drugs. A second study presented in London analyzed data from several studies and found that in a large population of research participants with cognitive concerns brain amyloid PET scans led to a change in diagnosis in approximately  of cases. People should know whats coming said Dr. Maria Carrillo chief science officer for the Alzheimers Assn. The Centers for Medicare  Medicaid Services has given amyloid scans a provisional approval meaning they do not routinely pay for them. The results may guide the agency to rethink its position she added. The PET scan bore bad news for Ken Lehmann who enrolled last year in the IDEAS trial short for Imaging Dementia  Evidence for Amyloid Scanning. After his long slow decline that has flummoxed doctors Lehmanns brain scan clearly showed he has Alzheimers disease. The certainty that has brought has been a long time coming. When Lehmann began withdrawing from friends forgetting to pay bills and having trouble following conversations he was just . Now hes . Ken had always been considered a Renaissance man  a furniture company executive who rebuilt Porsches played basketball and loved to entertain friends said his wife Mary Margaret Lehmann. But as years passed his judgment seemed off. He would lose track of points he was making and sometimes of where he was at.  It would take the loss of their home and a business bankruptcy for the Lehmanns to demand answers to what was going on. In  they moved from Sacramento to Edina Minn. to live with a daughter. And there at last they found a neurologist who despite initial skepticism but he presents so well the doctor proclaimed diagnosed dementia. For the Lehmanns and many patients and families like them  as well as for neurologists  that diagnosis is often just the beginning of a deeper mystery. Alzheimers disease is the most feared and most common form of dementia accounting for between  and  of all dementia cases diagnosed. But at least seven other forms of dementia and dementia linked to the movement disorder Parkinsons disease can cause loss of memory reasoning judgment and the ability to speak comprehend and care for oneself. To the estimated  million Americans living with some form of cognitive impairment telling the difference could make a significant difference. Dementia forms with different origins progress differently or sometimes not at all. They respond best to different medications and will come to require different levels of care and treatment. Some though not Alzheimers can even be reversed with treatment. Being able to distinguish which form of dementia a patient has should help doctors and caregivers to make better choices. But its a question that until recently could be answered only after death. At that point a postmortem examination of the brain could be done to look for the builtup clumps and tangles of betaamyloid proteins the overall shrinkage and the loss of neurons in the brains hippocampus that are collectively the hallmarks of Alzheimers. No more. Improved medical imaging technologies developed over the last decade have made it possible to peer inside the brain of a living patient detect and measure the accumulation of betaamyloid and make a definitive diagnosis.  In  the Food and Drug Administration took a first step in making such imaging possible giving its blessing to the imaging agent florbetapir F which binds to amyloid aggregates in the brain and allows a PET scan to be used to make the diagnosis. In  two new imaging agents won FDA approval and new imaging agents and techniques promise ever more precise means to visualize and diagnose Alzheimers in the brain. On Wednesday research published in the journal Neurology http suggested that transcranial magnetic stimulation a technique that can selectively turn up or down activity in different parts of the brain could prove useful in distinguishing between Alzheimers disease from frontotemporal dementia. In many ways Ken Lehmanns symptoms fit neatly into a diagnosis of frontotemporal dementia. A form of cognitive impairment that typically becomes evident earlier than most cases of Alzheimers FTD often affects judgment personality and verbal communication. This form of dementia progresses as inexorably as does Alzheimers. But its typical course differs slightly. As an enrollee in the IDEAS trial Lehmann was prepared to learn what it was he had. I had come to the conclusion they just dont know said Lehmann now  from his home in Minnesota. In seven years my journey of decline has been very miniscule and they dont know why. It turns out he added I have all the biomarkers of Alzheimers disease. Once he and his wife learned that they stepped up their preparations for further decline. And they redoubled their efforts to do things that bring joy and that may slow Kens decline as well. They follow a diet rich in fatty fish healthful fats and fruits and vegetables and Ken does woodworking. He also sings in a Minneapolis chorus Giving Voice with other dementia patients. He has regained a longlost ability to read music. Just not knowing is very disconcerting says Mary Margaret who is her husbands principal caregiver. I dont know what the timeline is but I now know what the needs are in terms of financial and legal needs and endoflife issues. Those all need to be planned for ahead of time and now we have all of that in place. To me thats a safety net."