Improving specificity of stimulation-based language mapping in stuttering glioma patients: A mixed methods serial case study

Leonie Kram; Beate Neu; Axel Schröder; Bernhard Meyer; Sandro M Krieg; Sebastian Ille

doi:10.1016/j.heliyon.2023.e21984

Improving specificity of stimulation-based language mapping in stuttering glioma patients: A mixed methods serial case study

Heliyon. 2023 Nov 7;9(11):e21984. doi: 10.1016/j.heliyon.2023.e21984. eCollection 2023 Nov.

Authors

Leonie Kram^{1

2}, Beate Neu¹, Axel Schröder¹, Bernhard Meyer¹, Sandro M Krieg^{1

2}, Sebastian Ille^{1

2}

Affiliations

¹ Department of Neurosurgery, Klinikum rechts der Isar, Technical University of Munich, Germany.
² Department of Neurosurgery, Heidelberg University Hospital, Ruprecht-Karls-University Heidelberg, Germany.

Abstract

Objective: Stimulation-based language mapping relies on identifying stimulation-induced language disruptions, which preexisting speech disorders affecting the laryngeal and orofacial speech system can confound. This study ascertained the effects of preexisting stuttering on pre- and intraoperative language mapping to improve the reliability and specificity of established language mapping protocols in the context of speech fluency disorders.

Method: Differentiation-ability of a speech therapist and two experienced nrTMS examiners between stuttering symptoms and stimulation-induced language errors during preoperative mappings were retrospectively compared (05/2018-01/2021). Subsequently, the impact of stuttering on intraoperative mappings was evaluated in all prospective patients (01/2021-12/2022).

Results: In the first part, 4.85 % of 103 glioma patients stuttered. While both examiners had a significant agreement for misclassifying pauses in speech flow and prolongations (Κ ≥ 0.50, p ≤ 0.02, respectively), less experience resulted in more misclassified stuttering symptoms. In one awake surgery case within the second part, stuttering decreased the reliability of intraoperative language mapping.Comparison with Existing Method(s): By thoroughly differentiating speech fluency symptoms from stimulation-induced disruptions, the reliability and proportion of stuttering symptoms falsely attributed to stimulation-induced language network disruptions can be improved. This may increase the consistency and specificity of language mapping results in stuttering glioma patients.

Conclusions: Preexisting stuttering negatively impacted language mapping specificity. Thus, surgical planning and the functional outcome may benefit substantially from thoroughly differentiating speech fluency symptoms from stimulation-induced disruptions by trained specialists.

Keywords: Direct cortical stimulation; Glioma; Language mapping; Navigated transcranial magnetic stimulation; Stuttering.