Effect of familiar content on paragraph comprehension in aphasia

Background: Previous research has shown that context improves aphasic individuals' auditory comprehension. The specific contextual information that has been identified as beneficial includes semantic constraints, semantic plausibility, both predictive and non‐predictive information, and familiar topics. However, context can also include familiar content such as the names of relatives, friends, local schools, and local stores.

Aims: The purpose of the present study was to assess the influence of familiar content on comprehension in individuals with aphasia. Specifically, it assessed whether individuals with aphasia answer questions about paragraphs more accurately when the paragraphs contain familiar content than when they do not.

Methods & Procedures: Eleven participants with aphasia and eleven participants without brain damage listened to short paragraphs that differed in the familiarity of the content included. In half of the paragraphs, the people and places were generic and not known specifically by the participants. In the other half, the people and places were known by the participants (as provided by a spouse or other close individual). Approximately half of the subsequent questions asked of the participants related to this targeted information and half related to other, more generic, information in the paragraphs.

Outcomes & Results: The questions relating to the paragraphs with the familiar content were answered more accurately than were the questions relating to the paragraphs with neutral content. For the participants with aphasia, this result occurred for the questions relating to both the targeted (and thus familiar) information and the non‐targeted or neutral information. The extent to which each participant with aphasia benefited from the familiar content did not relate to age, education, time‐post‐onset, or comprehension and naming skills.

Conclusions: These results suggest that familiar content may be another type of context that enhances comprehension skills in individuals with aphasia. The results are interpreted with respect to attention and domain knowledge concepts.     

Clinical features in a large Iranian family with a limb-girdle congenital myasthenic syndrome due to a mutation in DPAGT1

Mutations in DPAGT1 are a newly recognised cause of congenital myasthenic syndrome. DPAGT1 encodes an early component of the N-linked glycosylation pathway. Initially mutations in DPAGT1 have been associated with the onset of the severe multisystem disorder – congenital disorder of glycosylation type 1J. However, recently it was established that certain mutations in this gene can cause symptoms restricted to muscle weakness resulting from defective neuromuscular transmission. We report four cases from a large Iranian pedigree with prominent limb-girdle weakness and minimal craniobulbar symptoms who harbour a novel mutation in DPAGT1, c.652C>T, p.Arg218Trp. This myasthenic syndrome may mimic myopathic disorders and is likely under-diagnosed.     

Genetics of New-Onset Diabetes after Transplantation

New-onset diabetes after transplantation is a common complication that reduces recipient survival. Research in renal transplant recipients has suggested that pancreatic β-cell dysfunction, as opposed to insulin resistance, may be the key pathologic process. In this study, clinical and genetic factors associated with new-onset diabetes after transplantation were identified in a white population. A joint analysis approach, with an initial genome-wide association study in a subset of cases followed by de novo genotyping in the complete case cohort, was implemented to identify single-nucleotide polymorphisms (SNPs) associated with the development of new-onset diabetes after transplantation. Clinical variables associated with the development of diabetes after renal transplantation included older recipient age, female sex, and percentage weight gain within 12 months of transplantation. The genome-wide association study identified 26 SNPs associated with new-onset diabetes after transplantation; this association was validated for eight SNPs (rs10484821, rs7533125, rs2861484, rs11580170, rs2020902, rs1836882, rs198372, and rs4394754) by de novo genotyping. These associations remained significant after multivariate adjustment for clinical variables. Seven of these SNPs are associated with genes implicated in β-cell apoptosis. These results corroborate recent clinical evidence implicating β-cell dysfunction in the pathophysiology of new-onset diabetes after transplantation and support the pursuit of therapeutic strategies to protect β cells in the post-transplant period.One-year graft survival after renal transplantation is now excellent, exceeding 93% for organs donated after brain death and 96% for those from living donors.^1–3 Technical advancements in surgery, improved understanding of immunology, and innovative developments in pharmacology have altered the landscape of renal transplantation. The goal of preventing early graft loss has largely been achieved and arguably the greatest challenge now is the avoidance of late graft failure. Although there has been a considerable improvement in 1-year renal transplant survival, the rate of graft attrition after the first year remains frustratingly constant.^2,4New-onset diabetes after transplantation (NODAT) is a common and serious disorder that curtails recipient survival.^5–7 NODAT is associated with cardiovascular complications^8–11 and develops in 2%–50%¹² of renal transplant recipients. Approximately 50% of recipients with NODAT require insulin therapy.^{6–8,13–15} A number of clinical variables have been associated with NODAT, including black ethnicity, older recipient age, female sex, obesity, immunosuppression, and viral infections.^{5,6,8,13,16,17}Until recently, the pathophysiology of NODAT was considered to be analogous to type 2 diabetes mellitus. Renal transplant recipients have increased insulin resistance compared with transplant-naïve persons with normal renal function.¹⁸ In a nondiabetic renal transplant population, the main determinants of insulin resistance are obesity and corticosteroid therapy.¹⁹ Insulin resistance improves in renal transplant recipients after successful transplantation^20,21 and recipients have enhanced insulin sensitivity compared with dialysis patients.²² At 1 year, there is no significant difference in insulin resistance between renal transplant recipients with NODAT and those with normal glucose tolerance.^18,23 Furthermore, insulin resistance indices before transplantation and in the early post-transplant period do not predict NODAT development.¹¹Pancreatic β-cell dysfunction may prove to be the main pathologic contributor to NODAT. In glucose clamp studies, a deficit in insulin secretion was common to renal transplant recipients with NODAT.^18,20,21,24 There are a number of possible mechanisms for β-cell toxicity in renal transplantation, including hyperglycemia,²⁵ elevated free fatty acids,²⁶ and the effect of immunosuppressive medication.²⁷ A recent proof-of-concept clinical trial demonstrated that aggressive management of post-transplant hyperglycemia with insulin significantly reduced the 1-year incidence of NODAT.²⁸ This provides further evidence that post-transplant hyperglycemia plays a key role in NODAT development.This study investigates clinical and genetic factors associated with NODAT in a relatively large, white renal transplant population. Clinical variables were identified in a carefully phenotyped, ethnically homogeneous cohort. Initial exploratory analysis was conducted via a genome-wide association study (GWAS) in a subgroup of NODAT cases patients and controls to identify genetic variants associated with NODAT. De novo genotyping was then performed in a larger cohort of NODAT patients and controls to validate the findings.