| Authors | Chételat, , G. Ossenkoppele, R. Villemagne, V.L. Perrotin, A. Landeau, B. Mézenge, F. Jagust, W.J. Dore, V. Miller, B.L. Egret, S. Seeley, W.W. van der Flier, W.M. La Joie R. Ames, D. van Berckel, B.N.M. Scheltens, P. Barkhof, F Rowe, C.C. Masters, C.L. de La Sayette, V. Bouwman, F Rabinovici, G.D. |
|---|---|
| Type | Journal Article (Original Research) |
| Journal | Brain |
| Year of Publication | 2016 |
| URL | http://brain.oxfordjournals.org/content/brain/early/2016/06/27/brain.aww159.full.pdf |
| DOI | http://dx.doi.org/10.1093/brain/aww159 |
| Download |  brainaww159_full_.pdf (888.5 KB) |
| Abstract | About 15% of patients clinically diagnosed with Alzheimer's disease do not show high tracer retention on amyloid positon emission tomography imaging. The present study investigates clinical and demographic features, patterns of brain atrophy and hypometabolism and longitudinal clinical trajectories of these patients. Forty amyloid-negative patients carrying a pre-scan diagnosis of Alzheimer's disease dementia from four centres were included (11/29 females/males; mean age = 67 ± 9). Detailed clinical histories, including the clinical diagnoses before and after the amyloid scan and at follow-up, were collected. Patients were classified according to their pre-scan clinical phenotype as amnestic (memory predominant), non-amnestic (predominant language, visuospatial or frontal symptoms), or non-specific (diffuse cognitive deficits). Demographic, clinical, neuropsychological, magnetic resonance imaging and 18F-fluorodeoxyglucose positon emission tomography data were compared to 27 amyloid-positive typical Alzheimer's disease cases (14/13 females/males; mean age = 71 ± 10) and 29 amyloid-negative controls (15/14 females/males; mean age = 69 ± 12) matched for age, gender and education. There were 21 amnestic, 12 non-amnestic, and seven non-specific amyloid-negative Alzheimer's disease cases. Amyloid-negative subgroups did not differ in age, gender or education. After the amyloid scan, clinicians altered the diagnosis in 68% of amyloid-negative patients including 48% of amnestic versus 94% of non-amnestic and non-specific cases. Amnestic amyloid-negative cases were most often reclassified as frontotemporal dementia, non-amnestic as frontotemporal dementia or corticobasal degeneration, and non-specific as dementia with Lewy bodies or unknown diagnosis. The longer-term clinical follow-up was consistent with the post-scan diagnosis in most cases (90%), including in amnestic amyloid-negative cases whose post-positon emission tomography diagnosis remained Alzheimer's disease. While the non-amnestic and non-specific amyloid-negative cases usually showed patterns of atrophy and hypometabolism suggestive of another degenerative disorder, the amnestic amyloid-negative cases had subtle atrophy and hypometabolism, restricted to the retrosplenial/posterior cingulate cortex. Patients with a negative amyloid positon emission tomography scan following an initial clinical diagnosis of Alzheimer's disease have heterogeneous clinical presentations and neuroimaging profiles; a majority showed a clinical progression that was consistent with a neurodegenerative condition. In contrast, in the subgroup of amnestic amyloid-negative cases, the clinical presentation and follow-up usually remained consistent with Alzheimer's disease. An alternative diagnosis was not made in about half of the amnestic amyloid-negative cases, highlighting the need for a clinical framework and terminology to define these patients, who may have underlying limbic-predominant, non-amyloid-related pathologies.AbbreviationsAβneg-ADamyloid-negative probable Alzheimer's disease patientsAβneg-HCamyloid-negative healthy control subjectsAβpos-ADamyloid-positive probable Alzheimer's disease patients |
http://www.ibas.org.au/what-we-do/publications/3872827
Motor neurone disease (MND) causes the body's muscles to weaken. Breathing muscle weakness means that most people affected by MND will eventually lose the ability to take a deep breath and cough strongly....
RESPIRATORY BIOMARKERS IN MOTOR NEURONE DISEASE
The inability to breathe is unfortunately the most common cause of death in people living with Motor Neurone Disease (MND). Last year, our clinical research group in Melbourne reported that breathing...
Sleep apnea is a condition where breathing is abnormal during sleep. There are two main forms of sleep apnea: obstructive and central. For obstructive sleep apnea, breathing is reduced because the airway...
Kudos to Dr. Lauren Booker & Dr. Jen Cori on their JOEM publication examining fatigue detection alarms in rural truck drivers. Their study explores the alarms' effectiveness, accuracy, and habituation, offering key insights into fatigue management.
HONORING EXCELLENCE IN RESEARCH
Congratulations to Prof. Anne Holland and A/Prof. Narelle Cox for being featured in the NHMRC's 10 of the Best - 16th Edition. Their work exemplifies groundbreaking research delivering extraordinary outcomes.
WORLD SLEEP DAY ON 14TH MARCH 2025
The benefits of quality sleep and to acknowledge the issue of sleep problems and their medical, educational, and social aspects as well as the prevention and management of sleep disorders, is promoted on World Sleep Day on the 14th March 2025.
Grants Success: The Institute for Breathing and Sleep (IBAS) has received two research grants from the Austin Medical Research Foundation (AMRF) for 2025. Congratulations to Dr Charissa Zaga and Dr Catherine Hill from IBAS.
© 2025 Institute for Breathing and Sleep. All Rights Reserved. ABN 39 093 685 879
Powered by Helmut Design | Manage
