Cognitive Biomarkers in the Clinic: Lessons From Presurgical fMRI.

Cognitive biomarkers are vital and uniquely challenging clinical tools. There has been marked growth in neuroimaging-based cognitive biomarkers across the past 40 years with more in development (e.g.

Electrical cortical stimulation can impair production of the alphabet without impairing counting.

Neurosurgery has the potential to cure patients with drug-resistant focal epilepsy, but carries the risk of permanent language impairment when surgery involves the dominant hemisphere of the brain. This risk can be estimated and minimized using electrical stimulation mapping (ESM), which uses cognitive and linguistic tasks during cortical ESM to differentiate "eloquent" and "resectable" areas in the brain. One such task, counting, is often used to screen and characterize language during ESM in patients whose language abilities are limited.

Presurgical language fMRI: Technical practices in epilepsy surgical planning.

Little is known about how language functional MRI (fMRI) is executed in clinical practice in spite of its widespread use. Here we comprehensively documented its execution in surgical planning in epilepsy. A questionnaire focusing on cognitive design, image acquisition, analysis and interpretation, and practical considerations was developed.

Presurgical language fMRI: Clinical practices and patient outcomes in epilepsy surgical planning.

The goal of this study was to document current clinical practice and report patient outcomes in presurgical language functional MRI (fMRI) for epilepsy surgery. Epilepsy surgical programs worldwide were surveyed as to the utility, implementation, and efficacy of language fMRI in the clinic; 82 programs responded. Respondents were predominantly US (61%) academic programs (85%), and evaluated adults (44%), adults and children (40%), or children only (16%).

Language system organization in a quadrilingual with a brain tumor: Implications for understanding of the language network.

In pre-neurosurgery language mapping it is critical to identify language-specific regions in multilingual speakers. We conducted pre-operative functional magnetic resonance imaging, and intraoperative language mapping in the unique case of a highly proficient quadrilingual with a left frontal brain tumor who acquired her second language at age 5, and her third and fourth languages at 15. We found a predominantly different organization in each language with only a few areas shared by all 4 languages.

Role of the Wada test and functional magnetic resonance imaging in preoperative mapping of language and memory: two atypical cases.

The Wada test is an invasive procedure used to determine cerebral memory and language dominance as well as risk of cognitive deficits following neurosurgery. However, the potential risks of Wada testing have led some to consider foregoing Wada testing in candidates for resective epilepsy surgery with right hemispheric seizure onset. We present two atypical cases in which the Wada test showed unexpected memory and language lateralization.

Optimization of tractography of the optic radiations.

Imaging and delineation of the optic radiations (OpRs) remains challenging, despite repeated attempts to achieve reliable validated tractography of this complex structure. Previous studies have used varying methods to generate representations of the OpR which differ markedly from one another and, frequently, from the OpR's known structure. We systematically examined the influence of a key variable that has differed across previous studies, the tractography seed region, in 13 adult participants (nine male; mean age 31 years; SD 8.

What's the story? The tale of reading fluency told at speed.

Fluent readers process written text rapidly and accurately, and comprehend what they read. Historically, reading fluency has been modeled as the product of discrete skills such as single word decoding. More recent conceptualizations emphasize that fluent reading is the product of competency in, and the coordination of, multiple cognitive sub-skills (a multi-componential view).