Task description and commonly reported areas during intraoperative mapping
Language
Object namingassesses the ability to produce a noun (“table”) as depicted in a drawing/picture. This task assesses object recognition and conceptualization, semantic system, phonological output lexicon, phonological assembly, and articulatory programming. Several versions of this test include an introductory sentence on top of aneither black-and-white or colored picture or image. The introductory sentence is put to ask patients to produce a determiner and a noun (“This is … a table” instead of “table”). The production of the determiner and the noun (“a table”) in the sentence (“This is a table”) requires the production of grammatical information to encode number (a table v some tables), reference if already mentioned (the table v a table), and in some languages grammatical gender (French: la.femininetable v *il.masculinetable).Ojemann and Mateer [9] argued that the introductory sentence allows for the distinction of speech arrest (inability to speak) from anomic errors (patients read the introductory sentence but unable to produce the determiner and noun). This early interpretation is open to discussion, as patients may also show difficulties reading the introductory sentence, due to problems in accessing the orthographic input lexicon. This task has been traditionally used to map left perisylvian and subcortical brain areas [3].
Action namingassesses the ability to produce a verb (“running”) as depicted in a drawing/picture. This task is meant to assess similar language levels to object naming if patients are showna black/white drawing or a video of an action and then asked to answer with an infinitive (e.g., “to run”) or gerund (“running”). Additionally, to engage the production of further grammatical knowledge (e.g., subject-verb agreement, time reference) some groups askpatients to produce a verb in a sentence (“the girl… runs” or “she runs”) [11]. This task has been used to map left perisylvian and subcortical brain areas, with particular emphasis in frontal and parietal brain regions [3].
Readingassesses the ability to decode written language. If patients are asked to read words such as (“table”) out loud. This task assesses visual orthographic analysis, orthographic input lexicon, semantics system, phonological output lexicon, phonological assembly, and articulatory programming. Additionally, this task can be used to access words that are difficult to depict as well as to test irregular words (words with opaque orthography-to-phonology relationship: for example, the French word oignon, onion, is read out/ɔ.ɲɔ̃/) and non-words/pseudowords (letter sequences that are not represented in the vocabulary: bafiko). Some groups also use this task to ask patients to read sentences, typically, of no more than eight words. This task has been used to map left perisylvian and subcortical brain areas [3].
Pyramids and Palm Trees Test (semantic association)assesses “the person’s ability to access detailed semantic representations from words and from pictures” [6]. The stimulus item is in the top center of the page (pyramid) and two alternatives are presented below it: a target (palm tree) and a distractor (pine tree). The patient is asked to choose which of the two items is associated with the item presented on top and either point to it or say it out loud. Patients need to recognize the three items, retrieve their information, and perform the association. This task has been used to map left perisylvian and subcortical areas, particular emphasis has been given to this task as a complement to object-naming for subcortical mapping [2].
Word Repetitionassesses language routes that do not necessarily require semantic access such as the phonological input-to-output conversion. Patients are asked to repeat words “shirt” and non-words such as “lavica”. Non-word repetition task has been pointed as more sensitive than word repetition and object naming when mapping the left arcuate fasciculus [12]. This task has also been used for patients to repeat the target word when they produced it incorrectly during object naming [8]. In the latter case, repeating the word successfully may be used to indicate that the interruption during object naming was due to disrupting object recognition (if images are used) or access to the phonological/orthographic input lexicon (if spoken/written words are used).
Visual inattention
Line bisectionassesses the presence of spatial neglect. Patients are shown one or a series of straight black lines and are asked to indicate/mark with a pencil the center of each line. This task is used to map temporal and parietal lesions in the right hemisphere as well as lesions in the optic radiations [2; 3; 7].
Visual field taskassesses performance related to the correct access of visual information in the different quadrants. Patients are asked to fixate on a red cross located in the center of the screen and name or read the object or word that appears in two or four quadrants of the image [4, 10]. Stimuli in the left visual field will be initially received in the right hemisphere and stimuli in the right visual field will be initially processed by the left hemisphere. This task is used in lesions located similarly to line bisection as well as the posterior part of the temporal lobe and the occipital lobe [3].
Emotion recognition
Reading the Mind in the Eyes Testassesses low-level emotion recognition or mentalising. That is, the social and cognitive function enabling humans to attribute mental states to others [1]. Patients are shown a picture of a human face (mainly the eyes and eyebrows) with two words reflecting different mental states (e.g., “irritated” and “bored”). Then, they are asked to say the mental state that the face represented. This task has been traditionally used to map the right frontal lobe, even though it also requires a complex frontal, temporal, and parietal cortical network.Note that the intraoperative version of this task gives two possible answers to the patient [5], while the original task gives four possible answers [1].
References
(1)Baron-Cohen S, Jolliffe T, Mortimore C, Robertson M (1997a) Another advanced test of theory of mind: evidence from very high functioning adults with autism or Asperger Syndrome. J Child Psychol Psychiatry 38:813-822
(2)Bowers D, Heilman KM (1980) Pseudoneglect: effects of hemispace on a tactile line bisection task. Neuropsychologia 18:491-498
(3)Coello AF, Moritz-Gasser S, Martino J, Martinoni M, Matsuda R, Duffau H (2013) Selection of intraoperative tasks for awake mapping based on relationships between tumor location and functional networks: a review. J Neurosurg119:1380-1394
(4)Gras-Combe G, Moritz-Gasser S, Herbet G, Duffau H (2012) Intraoperative subcortical electrical mapping of optic radiations in awake surgery for glioma involving visual pathways: Clinical article.J Neurosurg117:466-473
(5)Herbet G, Lafargue G, Moritz-Gasser S, Bonnetblanc F, Duffau H (2015) Interfering with the neural activity of mirror-related frontal areas impairs mentalistic inferences.Brain StructFunct220:2159-2169
(6)Howard D, Patterson KE (1992)The Pyramids and Palm Trees Test: A test of semantic access from words and pictures Thames Valley Test Company, Bury St Edmunds
(7)Jewell G, McCourt ME (2000) Pseudoneglect: a review and meta-analysis of performance factors in line bisection tasks.Neuropsychologia 38:93-110
(8)Moritz-Gasser S,Duffau H. (2013) Theanatomo-functional connectivity of word repetition: insights provided by awakebraintumorsurgery. Front Hum Neurosci.29: 1-4.
(9)Ojemann G, Mateer C (1979) Human language cortex: localization of memory syntax and sequential motor-phoneme identification systems. Science 205:1401-1403
(10)Robert E (2005) Linguistic procedure in ‘awake neurosurgery’. Stem- Spraak- en Taalpathologie 13:54-64
(11)Rofes A, Miceli G (2014) Language mapping with verbs and sentences in awake surgery: review.Neuropsychol Rev24:185-199
(12)Sierpowska J, Gabarrós A, Fernandez-Coello A, Camins À, Castañer S, Juncadella M, Rodríguez-Fornells A (2017) Words are not enough: nonword repetition as an indicator of arcuate fasciculus integrity during brain tumor resection.J Neurosurg 126:435-445