Sensory and motor electrophysiological mapping of the cerebellum in humans

Cerebellar damage during posterior fossa surgery in children can lead to ataxia and risk of cerebellar mutism syndrome. Compartmentalisation of sensorimotor and cognitive functions within the cerebellum have been demonstrated in animal electrophysiology and human imaging studies. Electrophysiological monitoring was carried out under general anaesthesia to assess the limb sensorimotor representation within the human cerebellum for assessment of neurophysiological integrity to reduce the incidence of surgical morbidities. Thirteen adult and paediatric patients undergoing posterior fossa surgery were recruited. Sensory evoked field potentials were recorded in response to mapping (n = 8) to electrical stimulation of limb nerves or muscles. For motor mapping (n = 5), electrical stimulation was applied to the surface of the cerebellum and evoked EMG responses were sought in facial and limb muscles. Sensory evoked potentials were found in two patients (25%). Responses were located on the surface of the right inferior posterior cerebellum to stimulation of the right leg in one patient, and on the left inferior posterior lobe in another patient to stimulation of left forearm. No evoked EMG responses were found for the motor mapping. The present study identifies challenges with using neurophysiological methods to map functional organization within the human cerebellum and considers ways to improve success.

Anaesthetic Management of Left Temporal Glioma Undergoing Awake Craniotomy

For an awake craniotomy, a 49 year old (ASA 2), 78 kg woman with type II DM was given regional anaesthesia (scalp block) with monitored anaesthesia care (MAC). She had a headache, which was primarily caused by a left temporal glioma. She was very apprehensive about having this procedure done while she was awake. Fentanyl and Dexmedetomidine infusions in combination with scalp block initially provided adequate operating conditions. Because the patient needed to be fully awake, alert and cooperative during the language and motor mapping, all sedation was turned off. Patient was cooperative and obeyed commands during motor and language mapping as well as during tumour excision. Patient underwent complete excision of tumour without any postoperative neurological deficit. The success of the awake craniotomy is dependent on the patient cooperation, anaesthesiologist's experience, adequate intraoperative analgesia coverage, careful sedation titration, and meticulous planning.

SURG-03. FUNCTIONAL OUTCOMES OF LASER INTERSTITIAL THERMAL THERAPY (LITT) VERSUS RESECTION IN THE TREATMENT OF LESIONS IN OR NEAR THE PRIMARY MOTOR CORTEX

INTRODUCTION Laser interstitial thermal therapy (LITT) is a minimally-invasive treatment option for radiographically-progressive (RP) brain metastases. This study compares the functional outcomes of LITT vs resection (RS) for lesions in or near the primary motor cortex (PMC). METHODS Retrospective review was performed of patients treated for PMC lesions by LITT or RS. Functional outcomes were graded relative to pre-treatment symptoms and categorized as improved, stable, or worsened at 30, 90, and 180 days post-LITT/RS. RESULTS 36 patients were identified with median follow-up of 194 days (IQR 72-503), age 64 years (57-72), and estimated baseline KPS 80 (80-90). 35 (98%) had pre-treatment weakness or motor seizure; 15 (42%) received LITT and 21 (58%) RS; all RS were performed with intra-operative motor mapping while LITT were not. All LITT patients were treated for RP lesions (radiation necrosis (RN) or disease progression) vs. 24% of RS patients (p< 0.01). LITT patients trended towards smaller lesions (1.9 cm vs 2.7 cm, p=0.03) and were more likely to show RN (67% vs 5%, p< 0.01) and be discharged home (87% vs 52%, p=0.04), with shorter ICU (0 vs 1 day, p< 0.01) and hospital stays (1 vs. 2 days, p< 0.01). At 30 days, 89% of surviving patients who received RS had stable or improved symptoms, compared to 46% of the LITT cohort (p=0.02). At 90 days, the difference was 88% to 50% (p=0.07), and at 180 days 100% to 80% (p=0.2941). CONCLUSIONS In the short term (30 days), patients with PMC lesions have better functional outcomes when treated with RS compared to LITT, while those who survive to the 180-day timepoint experience similar outcomes. These differences are likely due to transient, expected post-LITT edema that subsides with time. Taken together, prognosis and patient priorities are important considerations in the decision between LITT and RS.

Auditory-Motor Mapping Training Facilitates Speech and Word Learning in Tone Language–Speaking Children With Autism: An Early Efficacy Study

Purpose It has been reported that tone language–speaking children with autism demonstrate speech-specific lexical tone processing difficulty, although they have intact or even better-than-normal processing of nonspeech/melodic pitch analogues. In this early efficacy study, we evaluated the therapeutic potential of Auditory-Motor Mapping Training (AMMT) in facilitating speech and word output for Mandarin-speaking nonverbal and low-verbal children with autism, in comparison with a matched non–AMMT-based control treatment. Method Fifteen Mandarin-speaking nonverbal and low-verbal children with autism spectrum disorder participated and completed all the AMMT-based treatment sessions by intoning (singing) and tapping the target words delivered via an app, whereas another 15 participants received control treatment. Generalized linear mixed-effects models were created to evaluate speech production accuracy and word production intelligibility across different groups and conditions. Results Results showed that the AMMT-based treatment provided a more effective training approach in accelerating the rate of speech (especially lexical tone) and word learning in the trained items. More importantly, the enhanced training efficacy on lexical tone acquisition remained at 2 weeks after therapy and generalized to untrained tones that were not practiced. Furthermore, the low-verbal participants showed higher improvement compared to the nonverbal participants. Conclusions These data provide the first empirical evidence for adopting the AMMT-based training to facilitate speech and word learning in Mandarin-speaking nonverbal and low-verbal children with autism. This early efficacy study holds promise for improving lexical tone production in Mandarin-speaking children with autism but should be further replicated in larger scale randomized studies. Supplemental Material https://doi.org/10.23641/asha.16834627

Impacting the Treatment of Highly Eloquent Supratentorial Cerebral Cavernous Malformations by Noninvasive Functional Mapping—An Observational Cohort Study

BACKGROUND Cerebral cavernous malformations (CCM) may cause cavernoma-related epilepsy (CRE) and intracranial hemorrhage (ICH). Functional mapping has shown its usefulness during the resection of eloquent lesions including the treatment of brain arteriovenous malformations. OBJECTIVE To evaluate the impact of noninvasive functional mapping on decision-making and resection of eloquently located CCM. METHODS Of 126 patients with intracranial cavernomas, we prospectively included 40 consecutive patients (31.7%) with highly eloquent CCM between 2012 and 2020. We performed functional mapping via navigated transcranial magnetic stimulation (nTMS) motor mapping in 30 cases and nTMS language mapping in 20 cases. Twenty patients suffered from CRE. CCM caused ICH in 18 cases. RESULTS We used functional mapping data including function-based tractography in all cases. Indication toward (31 cases) or against (9 cases) CCM resection was influenced by noninvasive functional mapping in 36 cases (90%). We resected CCMs in 24 cases, and 7 patients refused the recommendation for surgery. In 19 and 4 cases, we used additional intraoperative neuromonitoring and awake craniotomy, respectively. Patients suffered from transient postoperative motor or language deficits in 2 and 2 cases, respectively. No patient suffered from permanent deficits. After 1 yr of follow-up, anti-epileptic drugs could be discontinued in all patients who underwent surgery but 1 patient. CONCLUSION Surgery-related deficit rates are low even for highly eloquent CCM and seizure outcome is excellent. The present results show that noninvasive functional mapping and function-based tractography is a useful tool for the decision-making process and during microsurgical resection of eloquently located CCM.