BOLD functional MRI may overlook activation areas in the damaged brain
Department of Neurosurgery, Nihon University School of Medicine, Tokyo, Japan. Acta neurochirurgica. Supplement
02/2003; 87(87):59-62. DOI: 10.1007/978-3-7091-6081-7_13
Clinical applications of blood-oxygenation-level-dependent contrast functional MRI (BOLD-fMRI) have been rapidly moving toward routine non-invasive cortical mapping in the patients with brain disorders. However, it is not yet clear whether the damaged brain shows same cerebral blood oxygenation (CBO) changes during neuronal activation as those in the normal adult. We compared the activation mapping obtained by BOLD-fMRI and the evoked-CBO changes measured by near infrared spectroscopy (NIRS) in normal adults (6 cases) and patients with damaged brain (6 cases of cerebral ischemia and 10 cases of brain tumors in or adjacent to the motor cortex). BOLD-fMRI demonstrated robust activation areas in the primary sensorimotor cortex (PSMC) during contralateral hand grasping tasks in all of the normal adults; however, in the cerebral ischemia (6 cases) and the brain tumors (2 cases), BOLD-fMRI demonstrated only limited activation areas in the PSMC on the lesion side during the task. NIRS demonstrated an increase of focal concentration of oxyhemoglobin and total hemoglobin at the PSMC during the task in all of the normal adults and the patients, indicating the presence of rCBF increase in response to neuronal activation. A focal concentration of deoxyhemoglobin decreased during the task in the normal adults, however, in the patients that showed limited activation areas by BOLD-fMRI, deoxyhemoglobin concentrations increased during the entire course of the task. In summary, the evoked-CBO changes occurring in the damaged brain differed from those in the normal brain. This indicates that BOLD-fMRI may overlook activation areas in the damaged brain.
Available from: Alexander & Andrew Fingelkurts
- "Of course, these group-mean values do not allow analysis of the topological peculiarities of EEG segment attributes and synchrony characteristics, but it was our deliberate choice. The differences in brain injuries among chronically immobile, dependent patients with severe brain damage, resulting in distortions of neuroanatomy secondary to atrophy and loss of both gray and white matter structures (Sakatani et al. 2003 "
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ABSTRACT: Although several studies propose that the integrity of neuronal assemblies may underlie a phenomenon referred to as awareness, none of the known studies have explicitly investigated dynamics and functional interactions among neuronal assemblies as a function of consciousness expression. In order to address this question, EEG operational architectonics analysis (Fingelkurts and Fingelkurts 2001, 2008) was conducted in patients in minimally conscious (MCS) and vegetative states (VS) to study the dynamics of neuronal assemblies and operational synchrony among them as a function of consciousness expression. We found that in minimally conscious patients and especially in vegetative patients neuronal assemblies got smaller, their life span shortened and they became highly unstable. Furthermore, we demonstrated that the extent/volume and strength of operational synchrony among neuronal assemblies was smallest or even absent in VS patients, intermediate in MCS patients, and highest in healthy fully conscious subjects. All findings were similarly observed in EEG alpha as well as beta1 and beta2 frequency oscillations. The presented results support the basic tenets of operational architectonics theory of brain-mind functioning and suggest that EEG operational architectonics analysis may provide an objective and accurate means of assessing signs of (un)consciousness in patients with severe brain injuries. Therefore, this methodological approach may complement the existing "gold standard" of behavioral assessment of this population of challenging patients and inform the diagnostic and treatment decision-making processes.
Cognitive Processing 10/2011; 13(2):111-31. DOI:10.1007/s10339-011-0416-x · 1.57 Impact Factor
Available from: Bernd Weber
- "Infarctions, brain edema, and cerebrovascular disease with stenoses of intra-and extracerebral arteries can lead to falsely localized activation or false-negative activation maps (Holodny et al., 2000; Carusone et al., 2002; Krings et al., 2002; Murata et al., 2002; Pineiro et al., 2002; D'Esposito et al., 2003; Sakatani et al., 2003; Rossini et al., 2004). In the vicinity of space-occupying glial (Holodny et al., 2000; Schreiber et al., 2000; Krings et al., 2002; Sakatani et al., 2003; Ulmer et al., 2003, 2004; Haberg et al., 2004; Fujiwara et al., 2004; Hou et al., 2006; Ruff et al., 2008) and nonglial lesions (Holodny et al., 2000; Pineiro et al., 2002), the generation of BOLD-contrast enhancement can be either increased or decreased. A reason for this can be disturbed blood flow or vascular autoregulation in the vicinity of these lesions (Gao et al., 1996; Pronin et al., 1997). "
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ABSTRACT: Several small patient studies and case reports raise concerns that the reliability of functional magnetic resonance imaging (fMRI) may be impaired in the vicinity of cerebral lesions. This could affect the clinical validity of fMRI for presurgical language lateralization. The current study sets out to identify if a systematic effect of lesion type and localization on fMRI exists.
We classify lesions typically occurring in epilepsy patients according to (1) their potential to disturb blood oxygenation level dependent (BOLD)-effect generation or detection or to disturb spatial brain normalization, and (2) the proximity of lesions to protocol-specific volumes of interest (VOIs). The effect of lesions is evaluated through the examination of 238 epilepsy patients and a subgroup of 37 patients with suspected unilateral left-language dominance according to the Wada test.
Patients with fMRI-critical lesions such as cavernomas, gliomas, and mass defects close to VOIs, or with severe atrophy, show lower lateralization indices (LIs) and more often discordant language lateralization with the Wada test than do patients without such lesions.
This study points seriously toward fMRI-language lateralization being sensitive to cerebral lesions. Some lesion types and locations are more critical than others. Our results question the noncritical application of fMRI in patients with cerebral lesions.
Epilepsia 05/2009; 50(10):2213-24. DOI:10.1111/j.1528-1167.2009.02102.x · 4.57 Impact Factor
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ABSTRACT: This single-case, multiple-control study illustrates the clinical use of ERPs as part of the linguistic and cognitive assessment of individuals who are unable to provide verbal or motor responses due to their multiple handicaps. The single-word receptive vocabulary of a 17-year-old patient with Cerebral Palsy (CP) and three age-matched controls was measured using an event-related potential (ERP) paradigm. The Peabody Picture Vocabulary Test-Revised (PPVT-R) was adapted for computer presentation, with three levels of difficulty (Preschool, Child, Adult). Individual pictures were presented successively, and correctly (congruent) or incorrectly (incongruent) named auditorially. ERP components were derived for both the congruent and incongruent picture-word pairs. As predicted, the N400 ERP component had a higher peak for the incongruent picture-word pairs at the Preschool and Child levels. At the Adult level, the ERP pattern was reversed (higher peak in congruent condition) for the CP patient and for two of the three controls and, it was substantially attenuated for the third control. These ERP findings indicated that picture-word pairs within the range of acquired receptive vocabulary were identified as correct or incorrect but picture-word pairs above an individual's level could not be differentiated as clearly. The findings demonstrate the clinical application of this paradigm to assessing receptive vocabulary in motor- and communication-impaired patients.
Journal of Clinical and Experimental Neuropsychology 03/1995; 17(1):9-19. DOI:10.1080/13803399508406576 · 2.08 Impact Factor
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