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Purpose: To evaluate the use of the cortiQ-based mapping system (g.tec medication engineering GmbH, Austria) for real-time functional mapping (RTFM) and to compare it to results from electrical cortical stimulation mapping (ESM) and functional magnetic resonance imaging (fMRI)., Methods: Electrocorticographic activity was recorded in 3 male patients with intractable epilepsy by using cortiQ mapping system and analyzed in real time. Activation related to motor, sensory, and receptive language tasks was determined by evaluating the power of the high gamma frequency band (60-170 Hz). The sensitivity and specificity of RTFM were tested against ESM and fMRI results., Results: "Next-neighbor" approach demonstrated [sensitivity/specificity %] (1) RTFM against ESM: 100.00/79.70 for hand motor; 100.00/73.87 for hand sensory; -/87 for language (it was not identified by the ESM); (2) RTFM against fMRI: 100.00/84.4 for hand motor; 66.70/85.35 for hand sensory; and 87.85/77.70 for language., Conclusions: The results of the quantitative "next-neighbor" RTFM evaluation were concordant to those from ESM and fMRI. The RTFM correlates well with localization of hand motor function provided by ESM and fMRI, which may offer added localization in the operating room and guidance for extraoperative ESM mapping. Real-time functional mapping correlates with fMRI language activation when ESM findings are negative. It has fewer limitations than ESM and greater flexibility in activation paradigms and measuring responses.

Accurate language localization expands surgical treatment options for epilepsy patients and reduces the risk of postsurgery language deficits. Electrical cortical stimulation mapping (ESM) is considered to be the clinical gold standard for language localization. While ESM affords clinically valuable results, it can be poorly tolerated by children, requires active participation and compliance, carries a risk of inducing seizures, is highly time consuming, and is labor intensive. Given these limitations, alternative and/or complementary functional localization methods such as analysis of electrocorticographic (ECoG) activity in high gamma frequency band in real time are needed to precisely identify eloquent cortex in children. In this case report, the authors examined 1) the use of real-time functional mapping (RTFM) for language localization in a high gamma frequency band derived from ECoG to guide surgery in an epileptic pediatric patient and 2) the relationship of RTFM mapping results to postsurgical language outcomes. The authors found that RTFM demonstrated relatively high sensitivity (75%) and high specificity (90%) when compared with ESM in a "next-neighbor" analysis. While overlapping with ESM in the superior temporal region, RTFM showed a few other areas of activation related to expressive language function, areas that were eventually resected during the surgery. The authors speculate that this resection may be associated with observed postsurgical expressive language deficits. With additional validation in more subjects, this finding would suggest that surgical planning and associated assessment of the risk/benefit ratio would benefit from information provided by RTFM mapping.

SIGFRIED (SIGnal modeling For Real-time Identification and Event Detection) software provides real-time functional mapping (RTFM) of eloquent cortex for epilepsy patients preparing to undergo resective surgery. This study presents the first application of paradigms used in functional magnetic resonance (fMRI) and electrical cortical stimulation mapping (ESM) studies for shared functional cortical mapping in the context of RTFM. Results from the 3 modalities are compared. A left-handed 13-year-old male with intractable epilepsy participated in functional mapping for localization of eloquent language cortex with fMRI, ESM, and RTFM. For RTFM, data were acquired over the frontal and temporal cortex. Several paradigms were sequentially presented: passive (listening to stories) and active (picture naming and verb generation). For verb generation and story processing, fMRI showed atypical right lateralizing language activation within temporal lobe regions of interest and bilateral frontal activation with slight right lateralization. Left hemisphere ESM demonstrated no eloquent language areas. RTFM procedures using story processing and picture naming elicited activity in the right lateral and basal temporal regions. Verb generation elicited strong right lateral temporal lobe activation, as well as left frontal lobe activation. RTFM results confirmed atypical language lateralization evident from fMRI and ESM. We demonstrated the feasibility and usefulness of a new RTFM stimulation paradigm during presurgical evaluation. Block design paradigms used in fMRI may be optimal for this purpose. Further development is needed to create age-appropriate RTFM test batteries.

Patients with obsessive-compulsive disorder (OCD) often report sensory intolerances which may lead to significant functional impairment. This study used auditory evoked fields (AEFs) to address the question of whether neural correlates of sensory auditory information processing differ in youth with OCD compared with healthy comparison subjects (HCS). AEFs, recorded with a whole head 275-channel magnetoencephalography system, were elicited in response to binaural auditory stimuli from 10 pediatric subjects with OCD (ages 8-13, mean 11 years, 6 males) and 10 age- and gender-matched HCS. Three major neuromagnetic responses were studied: M70 (60-80 ms), M100 (90-120 ms), and M150 (130-190 ms). When compared with HCS, subjects with OCD demonstrated delayed latency of the M100 response. In subjects with OCD the amplitude of the M100 and M150 responses was significantly greater in the right hemisphere compared with the left hemisphere. Current results suggest that when compared with HCS, subjects with OCD have altered auditory information processing, evident from the delayed latency of the M100 response, which is thought to be associated with the encoding of physical stimulus characteristics. Interhemispheric asymmetry with increased M100 and M150 amplitudes over the right hemisphere compared with the left hemisphere was found in young OCD subjects. These results should be interpreted with caution due to the high variability rate of responses in both HCS and OCD subjects, as well as the possible effect of medication in OCD subjects., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Planning for epilepsy surgery depends substantially on the localization of brain cortical areas responsible for sensory, motor, or cognitive functions, clinically also known as eloquent cortex. In this paper, we present the novel software package 'cortiQ' that allows clinicians to localize eloquent cortex, thus providing a safe margin for surgical resection with a low incidence of neurological deficits. This software can be easily used in addition to traditional mapping procedures such as the electrical cortical stimulation (ECS) mapping. The software analyses task-related changes in gamma activity recorded from implanted subdural electrocorticography electrodes using extensions to previously published methods. In this manuscript, we describe the system's architecture and workflow required to obtain a map of the eloquent cortex. We validate the system by comparing our mapping results with those acquired using ECS mapping in two subjects. Our results indicate that cortiQ reliably identifies eloquent cortex much faster (several minutes compared to an hour or more) than ECS mapping. Next-neighbour analyses show that there are no false positives and an average of 1.24% false negatives.

Purpose: We aimed to determine the changes in neural correlates of auditory information processing such as auditory detection, encoding, and sensory discrimination in pediatric patients with intractable epilepsy., Methods: In this magnetoencephalography (MEG) study, 10 patients and 10 age- and gender-matched healthy controls were investigated with the multi-feature mismatch negativity (MMN) paradigm. Latencies and amplitudes of M100, M150, M200, and MMN event-related fields were evaluated., Results: All event-related fields in response to standard stimuli (M100, M150 and M200) and responses to occasional five deviant sounds, deviating from the standard stimuli either in duration, frequency, intensity, location, or by including a silent gap were reduced in amplitude in epilepsy patients compared with healthy controls., Conclusions: Our study suggests that auditory information processing is impaired in patients with drug-resistant epilepsy, being evident both in stimulus feature encoding (as reflected by changes of early event-related components, e.g., M100) and in cortical sound discrimination (as reflected by MMNm). The neural changes involving diminished M100 as well as MMNms for all five deviant sound types suggest wide-spread auditory information processing impairments in these patients., (Copyright © 2010 Elsevier B.V. All rights reserved.)