Conventional magnetic resonance imaging in confirmed progressive supranuclear palsy and multiple system atrophy

Conventional magnetic resonance imaging (cMRI) is often used to aid the diagnosis of progressive supranuclear palsy (PSP) and multiple system atrophy (MSA), but its ability to predict the histopathological diagnosis has not been systematically studied. cMRI from 48 neuropathologically confirmed cases, including PSP (n = 22), MSA (n = 13), Parkinson's disease (PD) (n = 7), and corticobasal degeneration (n = 6), and controls (n = 9) were assessed blinded to clinical details and systematically rated for reported abnormalities. Clinical diagnosis and macroscopic postmortem findings were retrospectively assessed. Radiological assessment of MRI was correct in 16 of 22 (72.7%) PSP cases and 10 of 13 (76.9%) MSA cases with substantial interrater agreement (Cohen's kappa 0.708; P < .001); no PSP case was misclassified as MSA or vice versa. MRI was less sensitive but more specific than clinical diagnosis in PSP and both more sensitive and specific than clinical diagnosis in MSA. The “hummingbird” and “morning glory” signs were highly specific for PSP, and “the middle cerebellar peduncle sign” and “hot cross bun” for MSA, but sensitivity was lower (up to 68.4%) and characteristic findings may not be present even at autopsy. cMRI, clinical diagnosis, and macroscopic examination at postmortem have similar sensitivity and specificity in predicting a neuropathological diagnosis. We have validated specific radiological signs in pathologically confirmed PSP and MSA. However, the low sensitivity of these and macroscopic findings at autopsy suggest a need for imaging techniques sensitive to microstructural abnormalities without regional atrophy. © 2012 Movement Disorder Society     

A Retrospective Review of Digit Span-Related Effort Indicators in Probable Alzheimer's Disease Patients

There has been extensive research on the use of both stand-alone and embedded measures of effort in neuropsychological testing; however, relatively few studies have reported on their utility in the context of dementia. Previous studies that have examined the specificity of traditionally used cut-scores on embedded measures of effort with dementia samples have largely found high rates of false positive errors. The present study examined the specificity of several Digit Span derived embedded measures of effort in a large clinical sample of patients with probable Alzheimer's disease stratified by level of dementia severity. Of the measures that were examined, only the Vocabulary – Digit Span score demonstrated promising specificity through the moderate level of dementia severity. All of the remaining indices, including Reliable Digit Span, Digit Span Age-Corrected Scaled Score, and Longest Digits Forward (1 & 2 Trials), yielded unacceptable rates of false positive errors as dementia severity increased. The implications for these findings are discussed, including the limitations of importing methods of assessing effort from one sample to another.     

Laparoscopic Heller's myotomy for achalasia after gastric bypass: A case report

INTRODUCTIONDisorders of the oesophagus have been linked to surgical bariatric procedures and obesity. However the relationship between achalasia and gastric bypass is not clearly understood and has only recently been reported following gastric bypass.PRESENTATION OF CASEWe present the case of a 53-year-old woman who re-presented following a gastric bypass with a new diagnosis of achalasia. This was treated successfully with laparoscopic Heller's Myotomy with discharge from hospital 10 days post operatively.DISCUSSIONIt is not clear whether achalasia is a complication of gastric bypass procedures. This is only the second reported case of the condition developing after this operation. The mechanism by which it may develop is yet to be clearly established.CONCLUSIONThis case highlights the need to investigate further a possible link between achalasia and gastric bypass and to manage susceptible patients accordingly in the pre-operative stage.     

Synthesis and Characterization of Holmium-Doped Iron Oxide Nanoparticles

Rare earth atoms exhibit several interesting properties, for example, large magnetic moments and luminescence. Introducing these atoms into a different matrix can lead to a material that shows multiple interesting effects. Holmium atoms were incorporated into an iron oxide nanoparticle and the concentration of the dopant atom was changed in order to determine its influence on the host crystal. Its magnetic and magneto-optical properties were investigated by vibrating sample magnetometry and Faraday rotation measurements. The luminescent characteristics of the material, in solution and incorporated in a polymer thin film, were probed by fluorescence experiments.