Altered microstructure of the contralesional ventral premotor cortex and motor output after stroke

Cortical thickness analyses have provided valuable insights into changes in cortical brain structure after stroke and their association with recovery. Across studies though, relationships between cortical structure and function show inconsistent results. Recent developments in diffusion-weighted imaging of the cortex have paved the way to uncover hidden aspects of stroke-related alterations in cortical microstructure, going beyond cortical thickness as a surrogate for cortical macrostructure. We re-analysed clinical and imaging data of 42 well-recovered chronic stroke patients from 2 independent cohorts (mean age 64 years, 4 left-handed, 71% male, 16 right-sided strokes) and 33 healthy controls of similar age and gender. Cortical fractional anisotropy and cortical thickness values were obtained for six key sensorimotor areas of the contralesional hemisphere. The regions included the primary motor cortex, dorsal and ventral premotor cortex, supplementary and pre-supplementary motor areas, and primary somatosensory cortex. Linear models were estimated for group comparisons between patients and controls and for correlations between cortical fractional anisotropy and cortical thickness and clinical scores. Compared with controls, stroke patients exhibited a reduction in fractional anisotropy in the contralesional ventral premotor cortex (P = 0.005). Fractional anisotropy of the other regions and cortical thickness did not show a comparable group difference. Higher fractional anisotropy of the ventral premotor cortex, but not cortical thickness, was positively associated with residual grip force in the stroke patients. These data provide novel evidence that the contralesional ventral premotor cortex might constitute a key sensorimotor area particularly susceptible to stroke-related alterations in cortical microstructure as measured by diffusion MRI and they suggest a link between these changes and residual motor output after stroke.

BRCA testing in unaffected young women in the United States, 2006-2017

BACKGROUND

The discovery of the BRCA gene in the 1990s created an opportunity for individualized cancer prevention. BRCA testing in young women before cancer onset enables early detection of those with an increased cancer risk and creates an opportunity to offer lifesaving prophylactic procedures and medications. This study assessed trends in BRCA testing in women younger than 40 years without diagnosed breast or ovarian cancer (unaffected young women [UYW]) for cancer prevention between 2006 and 2017 in the United States.

METHODS

This study included 93,278 adult women 18 to 65 years old with insurance claims for BRCA testing between 2006 and 2017 from the de-identified Optum Clinformatics Data Mart database. The data contained medical claims and administrative information from privately insured individuals in the United States. The proportion of BRCA testing in UYW younger than 40 years among adult women aged 18 to 65 years who received BRCA testing was assessed.

RESULTS

In 2006, only 10.5% of the tests were performed in UYW. The proportion of BRCA tests performed in UYW increased significantly to 25.5% in 2017 (annual percentage change for the 2006-2017 period, 6.9; 95% confidence interval, 6.4-7.3; P < .001). The increased trend in the proportion of BRCA tests in UYW significantly differed by region of residence and family history of breast or ovarian cancer.

CONCLUSIONS

Over the past decade, there was increased use of BRCA testing for cancer prevention. Additional efforts are needed to maximize the early detection of women with BRCA pathogenic variants so that these cancers may be prevented.

EEG of asymptomatic first-degree relatives of patients with juvenile myoclonic, childhood absence and rolandic epilepsy: a systematic review and meta-analysis

Rolandic (RE), childhood absence (CAE) and juvenile myoclonic (JME) epilepsy encompass centrotemporal sharp waves, 3-Hz spike waves and >3-Hz spike or polyspike waves, respectively. Evidence abounds for genetic roles in all three syndromes, yet involved genes for the vast majority of patients remain unknown. It has long been proposed that while each disease is genetically complex, its specific EEG trait may represent a genetically simpler endophenotype. This meta-analysis of the literature focuses on the frequency of EEG traits in clinically unaffected first-degree relatives towards determining inheritance patterns of the EEG endophenotypes. We used the Preferred Reporting Items for Systematic Review and Meta-Analysis for protocols (PRISMA-P) and searched Medline, EMBASE, CINHAL and the Cochrane Central Register of Controlled Trials. Following extensive screening, 15 studies were included with a total of 3,858 asymptomatic relatives. The prevalence of 'abnormal' EEG waves was 21%, 42% and 33% for JME, CAE and RE, respectively, close to what would be expected based on Mendelian inheritance. However, breaking down the reported EEG abnormalities, most consisted not of the respective EEG signature traits -prevalences of which were as low as 5%- but of non-specific EEG 'abnormalities'/variants. Prevalence of non-specific EEG 'abnormalities'/variants in the general population ranges from 0.1 to 10%. Underlying this 100-fold-wide range is a spectrum of what is considered 'abnormal' or variant. The prevalences of 'abnormalities'/variants in asymptomatic siblings in RE, CAE and JME significantly exceed even the highest value in the general population and fall within Mendelian expectations. These results suggest that EEG 'abnormalities'/variants shared with the general population are enriched in the three syndromes and are endophenotypes inherited in a genetically simple near-Mendelian fashion. Future work with modern EEG variant definitions should uncover genetic variants contributing to neuronal hypersynchrony in epilepsy.