Assessment of wakefulness during awake craniotomy to predict intraoperative language performance

Abstract

OBJECTIVEMaximal safe tumor resection in language areas of the brain relies on a patient’s ability to perform intraoperative language tasks. Assessing the performance of these tasks during awake craniotomies allows the neurosurgeon to identify and preserve brain regions that are critical for language processing. However, receiving sedation and analgesia just prior to experiencing an awake craniotomy may reduce a patient’s wakefulness, leading to transient language and/or cognitive impairments that do not completely subside before language testing begins. At present, the degree to which wakefulness influences intraoperative language task performance is unclear. Therefore, the authors sought to determine whether any of 5 brief measures of wakefulness predicts such performance during awake craniotomies for glioma resection.METHODSThe authors recruited 21 patients with dominant hemisphere low- and high-grade gliomas. Each patient performed baseline wakefulness measures in addition to picture-naming and text-reading language tasks 24 hours before undergoing an awake craniotomy. The patients performed these same tasks again in the operating room following the cessation of anesthesia medications. The authors then conducted statistical analyses to investigate potential relationships between wakefulness measures and language task performance.RESULTSRelative to baseline, performance on 3 of the 4 objective wakefulness measures (rapid counting, button pressing, and vigilance) declined in the operating room. Moreover, these declines appeared in the complete absence of self-reported changes in arousal. Performance on language tasks similarly declined in the intraoperative setting, with patients experiencing greater declines in picture naming than in text reading. Finally, performance declines on rapid counting and vigilance wakefulness tasks predicted performance declines on the picture-naming task.CONCLUSIONSCurrent subjective methods for assessing wakefulness during awake craniotomies may be insufficient. The administration of objective measures of wakefulness just prior to language task administration may help to ensure that patients are ready for testing. It may also allow neurosurgeons to identify patients who are at risk for poor intraoperative performance.

Glioblastoma remodeling of neural circuits in the human brain decreases survival

“…Electrocorticographic (ECoG) signals were acquired during a period after stopping the administration of anesthetics and the patient was judged to be alert and awake 39 . Intraoperative tasks consisted of naming pictorial representations of common objects and animals (Picture Naming, PN) and naming common objects and animals via auditory descriptions (Auditory Naming, AN) 40 .…”

Convergence of Heteromodal Lexical Retrieval in the Lateral Prefrontal Cortex

“…In addition to completing the QAB, each of the fifty-three participants performed four additional language tasks for use in lesion-symptom mapping. These tasks consisted of naming pictorial representations of common objects and animals (Picture Naming, PN), reading twosyllable text (Text Reading, TR), naming common objects and animals via auditory descriptions (Auditory Naming, AN) and describing line drawings with intact syntax (Syntax, Syn) 17,30 . The correct answers for all four tasks were matched on word frequency (i.e.…”

“…These incongruent results may reflect limitations of the previous methodologies used to study heteromodal lexical retrieval. Indeed, DES is restricted to regions exposed during brain mapping surgery, may be affected by the administration of anesthetics, and induces nonphysiologic, backward propagation of action potentials, thereby limiting its spatial specificity [15][16][17] . Furthermore, studies employing DES often do not assess subcortical tissue, differentiate speech arrest (i.e., a transient dysfunction in general speech production) from true anomia/dysnomia, or match stimuli on content category.…”

Convergence of Heteromodal Lexical Retrieval in the Lateral Prefrontal Cortex

“…In addition to completing the QAB, each of the fty-three participants performed four additional language tasks for use in lesion-symptom mapping. These tasks consisted of naming pictorial representations of common objects and animals (Picture Naming, PN), reading two-syllable text (Text Reading, TR), naming common objects and animals via auditory descriptions (Auditory Naming, AN) and describing line drawings with intact syntax (Syntax, Syn) 28,40 . The correct answers for all four tasks were matched on word frequency (i.e., commonality within the English language) using SUBTLEX WF scores provided by the Elixcon project (http://elexicon.wustl.edu/) and on content category 41 .…”

“…Incongruent results among existing studies may re ect limitations of the methodologies used to study heteromodal lexical retrieval. Indeed, DES is restricted to regions exposed during brain mapping surgery, may be affected by the administration of anesthetics, and induces non-physiologic, backward propagation of action potentials, thereby limiting its spatial speci city [26][27][28] . Furthermore, studies employing DES often do not assess subcortical tissue, differentiate speech arrest (i.e., a transient dysfunction in general speech production) from true anomia, or match stimuli on content category.…”