Speaking on the Edge: The protection of cognition after glioma surgery in eloquent areas

__Abstract__ This thesis investigates the long-term effects of awake glioma surgery in eloquent areas on cognition. The general assumption is that neurological recovery takes place within 3 months; no detailed cognitive follow-up studies have been conducted yet. Glioma patients (N=45) were tested pre- and postoperatively (3 months and 1 year) with a neuropsychological test-protocol assessing language, memory, attention and executive functions. Spontaneous speech was examined pre- and 3 months postoperatively as well as the relation of cognition and emotional factors on global quality of life (QoL). The influence of tumor- and treatment related factors on cognition was also investigated. Impairments were present in all cognitive domains on all test-moments. Permanent improvement postoperatively was found on a memory test. Language was the most sensitive domain for recovery. One language test deteriorated at short-term, and remained impaired at 1 year postoperatively. Two language tests improved between 3 months and 1 year. In addition to language tests, a spontaneous speech analysis was necessary to determine the quality of language production. A case study also underlined the importance of spontaneous speech monitoring intraoperatively to detect disturbances. Global QoL remained relatively stable, with depression as the only predictor for QoL change. Tumor- and treatment related factors were no clear risk-factors for cognitive change. Our results show that cognitive recovery takes longer than 3 months and that language, including spontaneous speech, is a crucial element of cognition to assess. Glioma surgery is possible without inducing major cognitive damage. Patients can be informed about the long-term cognitive prognosis

The CODECS study:COgnitive DEficits in Cerebellar Stroke

Part of the extra-pyramidal system, the cerebellum is more and more recognized by its non-motor functions known as the cerebellar cognitive affective syndrome. Several studies have identified disturbances specifically in executive and attentional functions after focal cerebellar lesions. However, most studies were performed in small and heterogeneous patient groups. Furthermore, there is a substantial variation in the methodology of assessment. Here, we present the results of a large and homogeneous cohort of patients with isolated uniform cerebellar lesions. After three months post-stroke all patients underwent structural neuroimaging to confirm an isolated lesion and were given neuropsychological testing. The results show that cerebellar lesions relate to mild but long-term cognitive impairment in a broad spectrum of neurocognitive functions compared to normative values. These findings confirm involvement of the cerebellum in cognitive processing and supports the theory of ‘dysmetria of thought’ based upon uniform cerebellar processing in multiple cognitive domains. This study highlights the following results: 1-Cognitive impairments after isolated cerebellar stroke is confirmed in several cognitive domains. 2-Semantic and phonemic fluency are most affected in cerebellar stroke patients. 3-Verbal deficits show an age-independent long term effect post-stroke and should be studied further in depth. 4-Cognitive disorders after cerebellar stroke are more prominent in women than men.</p

Spontaneous speech in patients with gliomas in eloquent areas before and after Surgery

Within a 300 word sample, spontaneous speech is analysed to ascertain Self-corrections, Repetitions, Type Token Ratio (all word types), Incomplete Sentences and Mean Length of Utterance (MLUw) using CLAN (MacWinney,1991). A naming test (Boston Naming Test) (Kaplan et al., 2001) and a category fluency test (animals) (Luteijn &amp; Barelds, 2004) were also assessed. A comparison was made between the spontaneous speech of patients and healthy controls, and of the patients pre-and post-operation. A correlation analysis was performed between the linguistic variables and tumour characteristics (localisation, volume, histopathology) and between the linguistic variables and the standardized language tasks

Differential contribution of language and executive functioning to verbal fluency performance in glioma patients

Glioma patients often suffer from deficits in language and executive functioning. Performance in verbal fluency (generating words within one minute according to a semantic category–category fluency, or given letter–letter fluency) is typically impaired in this patient group. While both language and executive functioning play a role in verbal fluency, the relative contribution of both domains remains unclear. We aim to retrospectively investigate glioma patients' performance on verbal and nonverbal fluency and to explore the influence of language and executive functioning on verbal fluency. Sixty-nine adults with gliomas in eloquent areas underwent a neuropsychological test battery (verbal fluency, nonverbal fluency, language, and executive functioning tests) before surgery (T1) and a subgroup of 31 patients also at three (T2) and twelve months (T3) after surgery. Preoperatively, patients were impaired in all verbal fluency tasks and dissociations were found based on tumour location. In contrast, nonverbal fluency was intact. Different language and executive functioning tests predicted performance on category fluency animals and letter fluency, while no significant predictors for category fluency professions were found. The longitudinal results indicated that category fluency professions deteriorated after surgery (T1–T2, T1–T3) and that nonverbal fluency improved after surgery (T1–T3, T2–T3). Verbal fluency performance can provide information on different possible underlying deficits in language and executive functioning in glioma patients, depending on verbal fluency task selection. Efficient task (order) selection can be based on complexity. Category fluency professions can be selected to detect more permanent long-term deficits.</p

Differential contribution of language and executive functioning to verbal fluency performance in glioma patients

Glioma patients often suffer from deficits in language and executive functioning. Performance in verbal fluency (generating words within one minute according to a semantic category–category fluency, or given letter–letter fluency) is typically impaired in this patient group. While both language and executive functioning play a role in verbal fluency, the relative contribution of both domains remains unclear. We aim to retrospectively investigate glioma patients' performance on verbal and nonverbal fluency and to explore the influence of language and executive functioning on verbal fluency. Sixty-nine adults with gliomas in eloquent areas underwent a neuropsychological test battery (verbal fluency, nonverbal fluency, language, and executive functioning tests) before surgery (T1) and a subgroup of 31 patients also at three (T2) and twelve months (T3) after surgery. Preoperatively, patients were impaired in all verbal fluency tasks and dissociations were found based on tumour location. In contrast, nonverbal fluency was intact. Different language and executive functioning tests predicted performance on category fluency animals and letter fluency, while no significant predictors for category fluency professions were found. The longitudinal results indicated that category fluency professions deteriorated after surgery (T1–T2, T1–T3) and that nonverbal fluency improved after surgery (T1–T3, T2–T3). Verbal fluency performance can provide information on different possible underlying deficits in language and executive functioning in glioma patients, depending on verbal fluency task selection. Efficient task (order) selection can be based on complexity. Category fluency professions can be selected to detect more permanent long-term deficits.</p

Localization patterns of speech and language errors during awake brain surgery:a systematic review

Awake craniotomy with direct electrical stimulation (DES) is the standard treatment for patients with eloquent area gliomas. DES detects speech and language errors, which indicate functional boundaries that must be maintained to preserve quality of life. During DES, traditional object naming or other linguistic tasks such as tasks from the Dutch Linguistic Intraoperative Protocol (DuLIP) can be used. It is not fully clear which speech and language errors occur in which brain locations. To provide an overview and to update DuLIP, a systematic review was conducted in which 102 studies were included, reporting on speech and language errors and the corresponding brain locations during awake craniotomy with DES in adult glioma patients up until 6 July 2020. The current findings provide a crude overview on language localization. Even though subcortical areas are in general less often investigated intraoperatively, still 40% out of all errors was reported at the subcortical level and almost 60% at the cortical level. Rudimentary localization patterns for different error types were observed and compared to the dual-stream model of language processing and the DuLIP model. While most patterns were similar compared to the models, additional locations were identified for articulation/motor speech, phonology, reading, and writing. Based on these patterns, we propose an updated DuLIP model. This model can be applied for a more adequate “location-to-function” language task selection to assess different linguistic functions during awake craniotomy, to possibly improve intraoperative language monitoring. This could result in a better postoperative language outcome in the future. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10143-022-01943-9

Language improvement after awake craniotomy in a 12-year-old child:illustrative case

BACKGROUND:Although the standard procedure to treat adult patients with lesions in eloquent brain areas is awake craniotomy with direct electrical stimulation, this procedure is not often used in children because of feasibility concerns. Some studies have shown that the procedure is feasible in children. They reported the postoperative language ability, which was not based on standardized language tests for children. To give an objective overview of preoperative assessment of the language ability of a child before and after this procedure, the authors described the perioperative course, including standardized language tests for children and the awake surgery setting, of a 12-year-old child undergoing awake craniotomy with brain mapping for the indication of cavernoma in the left somatosensory cortex close to the motor cortex. OBSERVATIONS:The patient performed better on language tests after surgery, showing that his language ability improved. He also cooperated well during the entire perioperative period. His mother was present during the awake surgery, and the patient tolerated the surgery well. LESSONS:The authors conclude that awake craniotomy is indeed feasible in a child and that it can even result in an improved postoperative language outcome. It is, however, crucial to carefully assess, inform, and monitor the child and their proxies.</p

Language improvement after awake craniotomy in a 12-year-old child:illustrative case

BACKGROUND:Although the standard procedure to treat adult patients with lesions in eloquent brain areas is awake craniotomy with direct electrical stimulation, this procedure is not often used in children because of feasibility concerns. Some studies have shown that the procedure is feasible in children. They reported the postoperative language ability, which was not based on standardized language tests for children. To give an objective overview of preoperative assessment of the language ability of a child before and after this procedure, the authors described the perioperative course, including standardized language tests for children and the awake surgery setting, of a 12-year-old child undergoing awake craniotomy with brain mapping for the indication of cavernoma in the left somatosensory cortex close to the motor cortex. OBSERVATIONS:The patient performed better on language tests after surgery, showing that his language ability improved. He also cooperated well during the entire perioperative period. His mother was present during the awake surgery, and the patient tolerated the surgery well. LESSONS:The authors conclude that awake craniotomy is indeed feasible in a child and that it can even result in an improved postoperative language outcome. It is, however, crucial to carefully assess, inform, and monitor the child and their proxies.</p