The Greek linguistic assessment for awake brain surgery: development process and normative data

ABSTRACT

Language mapping with direct electrical stimulation is considered the gold standard in surgical treatment of brain tumors. Assessing a variety of language functions intraoperatively can affect the extent of the tumor resection as well as the patient’s postoperative quality of life. Although most tests include preoperative sessions where tasks are personalised to each patient, normative data are essential since they can ensure that the presented stimuli can be responded appropriately. In this study, we describe the development and standardisation procedures of the first linguistic test in Greek, designed specifically for brain mapping during awake craniotomies. The tasks are developed to comply with the special conditions and restrictions of language assessment inside the operating room. Each task is controlled for various psycholinguistic and lexical variables and it is associated with specific neuroanatomical areas and linguistic processes. Our population consists of 80 right-handed, healthy, Greek-speaking individuals aged 20–60 years. We found only a few main effects and interactions of demographic variables on our test scores. Most differences were found between age groups, since older participants tend to perform slightly worse than younger ones. Therefore, percentiles and cut-off scores were calculated separately for each demographic group. Regarding the clinical application of GLAABS, we describe the procedures we followed to administer it to brain tumor patients from our department and also discuss how sensitivity and specificity can affect patients’ postoperative course.

KEYWORDS:

• Awake craniotomy
• language assessment
• brain mapping
• test development
• standardised test

Acknowledgments

We would like to thank the reviewers and the editor for the constructive comments that helped us to expand our knowledge and make this article better.

We would like to thank Anthi Zafeiri for her editing in English.

The present study is part of the doctoral research of the first author (C.P.) who is a Ph.D. student in the Department of Neurosurgery, Faculty of Medicine, University of Thessaly and receives a scholarship from the Greek State Scholarships Foundation (IKY).

Disclosure of interest

The authors report no conflict of interest.

Supplementary material

Supplemental data for this article can be accessed on the publisher’s website.

Notes

¹ Automated speech is based on overlearned sequences of words and can be produced with little awareness of meaning. It is elicited by asking the patient to count (e.g., 0–10), recite the days of the week, or say his or her name.

² Drawings were developed for the program “Teaching Greek Sign Language as First Language and Personalized Educational Program for Kids with Hearing Impairment” http://www.pi-schools.gr/programs/seppe/ppe/Eidiki_Agogi/ppe28.htm.

³ In this article, we use this term to refer to frequency of occurrence in Greek (written) language and particularly to the Zipf scale (Kyparissiadis et al., 2017), which is the most appropriate statistic to measure word frequency in psychological research (Van Heuven et al., 2014).

⁴ Ιt was not possible to match perfectly in number of phonemes or syllables so we tried to match them at least in terms of number of letters.

⁵ Unfortunately, it was not possible to apply this rule to every slide of this task.

⁶ Although traditional grammarians assume the SVO word order as the standard for the Greek language, in recent years this has been questioned. For more information see Roussou and Tsimpli (2006).

⁷ For more information regarding patient-clinician interaction, see Robert (2005).

Additional information

Funding

This research is co-financed by Greece and the European Union (European Social Fund – ESF) through the Operational Programme «Human Resources Development, Education and Lifelong Learning» in the context of the project “Strengthening Human Resources Research Potential via Doctorate Research” (MIS-5000432), implemented by the State Scholarships Foundation (ΙΚΥ); State Scholarships Foundation [2018-050-0502-12150]