Association between activity in the ventral premotor cortex and spinal cord activation during force generation-A combined cortico-spinal fMRI study

Force generation is a crucial element of dexterity and a highly relevant skill of the human motor system. How cerebral and spinal components interact and how spinal activation is associated with the activity in the cerebral primary motor and premotor areas is poorly understood. Here, we conducted combined cortico-spinal functional magnetic resonance imaging during a simple visually guided isometric force generation task in 20 healthy young subjects. Activation was localized in the right cervical spinal cord and left primary motor and premotor areas. The main finding is that spinal activation was negatively correlated with ventral premotor cortex activation. Spinal activation was furthermore significantly correlated with primary motor cortex activation, while increasing target forces led to an increase in the amount of activation. These data indicate that human premotor areas such as the ventral premotor cortex might be functionally connected to the lower cervical spinal cord contributing to distal upper limb functions, a finding that extends our understanding of human motor function beyond the animal literature.

Cortical thickness of contralesional cortices positively relates to future outcome after severe stroke

Imaging studies have evidenced that contralesional cortices are involved in recovery after motor stroke. Cortical thickness (CT) analysis has proven its potential to capture the changes of cortical anatomy, which have been related to recovery and treatment gains under therapy. An open question is whether CT obtained in the acute phase after stroke might inform correlational models to explain outcome variability. Data of 38 severely impaired (median NIH Stroke Scale 9, interquartile range: 6-13) acute stroke patients of 2 independent cohorts were reanalyzed. Structural imaging data were processed via the FreeSurfer pipeline to quantify regional CT of the contralesional hemisphere. Ordinal logistic regression models were fit to relate CT to modified Rankin Scale as an established measure of global disability after 3-6 months, adjusted for the initial deficit, lesion volume, and age. The data show that CT of contralesional cortices, such as the precentral gyrus, the superior frontal sulcus, and temporal and cingulate cortices, positively relates to the outcome after stroke. This work shows that the baseline cortical anatomy of selected contralesional cortices can explain the outcome variability after severe stroke, which further contributes to the concept of structural brain reserve with respect to contralesional cortices to promote recovery.

P11.15.B First multicentric real-life experience with the combination of lomustine and temozolomide in newly diagnosedMGMT promoter methylatedIDH wildtype glioblastoma

Background

The CeTeG/NOA-09 trial assessed in a randomized phase 3 setting, whether combined treatment of lomustine together with temozolomide was superior to temozolomide treatment alone in newly diagnosed MGMT (O(6)-methylguanine-DNA-methyltransferase) promoter methylated glioblastoma patients. Survival was significantly improved from 31.4 months with temozolomide alone to 48.1 months with the combination of lomustine plus temozolomide. In view of this encouraging data - suggesting this combination could have a significant impact on the survival of newly diagnosed glioblastoma patients - we were curious to assess safety and efficacy of this regimen under real-life conditions.

Material and Methods

We collected clinical and radiographic data from adult newly diagnosed MGMT promoter methylated IDH (isocitrate dehydrogenase) wildtype glioblastoma patients treated at five neuro-oncology centers in Germany. As a requirement for inclusion, first-line treatment with lomustine plus temozolomide had to be performed for at least six weeks (one course). The available radiographic data was independently reviewed by an experienced board-certified neuro-radiologist.

Results

In total, 70 patients were included. Median progression-free survival of the full cohort was 14.4 months and median overall survival was 36.0 months. Patients who received TTFields (Tumor Treating Fields) treatment for eight weeks or longer together with the combination of lomustine plus temozolomide (n=22, 31%) had a prolonged progression-free survival compared to those patients who received TTFields treatment less than eight weeks or did not receive treatment with TTFields (n=48, 69%) (21.5 months versus 11.2 months; HR: 2.118, 95% CI: 1.245-3.605; p=0.0105). In a multivariable Cox regression analysis the use of TTFields for eight weeks or longer together with the combination of lomustine plus temozolomide as well as the application of at least five courses of CeTeG therapy emerged as independent prognostic factors for progression-free survival and overall survival. Pseudoprogression occurred in n=16 (33%) of the patients. We observed no treatment related deaths and high-grade hematotoxicity in n=31 (44%) of the patients.

Conclusion

The results from this multicentric trial that investigated newly diagnosed MGMT promoter methylated IDH wildtype glioblastoma under real-life conditions indicate toxicity and survival estimates comparable to the CeTeG/NOA-09 trial. The use of TTFields for at least eight weeks in combination with this regimen was independently associated with extended progression-free and overall survival.

OS06.5.A Investigating safety and efficacy of TTFields prior and concomitant to radiotherapy in newly diagnosed glioblastoma - the PriCoTTF phase I/II trial

Background

The EF-14 phase III trial demonstrated improved survival for patients with newly diagnosed glioblastoma (nGBM) when TTFields therapy was added to adjuvant temozolomide chemotherapy. TTFields at 200 kHz are applied to the tumor utilizing arrays on the patients’ scalp. In preclinical studies, a synergistic inhibiting effect on glioblastoma cell proliferation was found for the combination of TTFields and radiotherapy. Based on these findings, we conduct the phase I/II PriCoTTF trial in adult nGBM patients to investigate the safety and efficacy of TTFields therapy initiated prior and concomitant to radiochemotherapy.

Material and Methods

Per study protocol, TTFields therapy is initiated following surgery and completed wound healing. Continuing throughout radiochemotherapy and adjuvant chemotherapy, TTFields therapy is used for approximately 9 months in total with TTFields rechallenge allowed at recurrence. Radiotherapy is conducted with arrays applied on the patients’ scalp. A total recruitment of 33 patients was sought, with 20 patients in arm A receiving normo-fractionated radiotherapy, and 13 elderly patients in arm B receiving hypo-fractionated radiotherapy. Safety and tolerance are the study’s primary endpoint, analyzed by a selection of pre-specified treatment-limiting toxicities (TLTs).

Results

A total of 33 patients have been enrolled. Patients' characteristics were mostly typical for glioblastoma, except for a rather low fraction of patients with gross total resection (GTR, 22.5%). The distribution of adverse events of common toxicity criteria (CTC) grade 3 or higher was comparable to that of established glioblastoma trials. Notably, skin toxicity of CTC grade 3 or higher was quite uncommon (n=2, 6%). As no patient developed TLTs, the study's primary endpoint was met. Median TTFields treatment duration was 8.4 months. Overall survival data was not mature enough (event rate 48%) to allow for a definite conclusion. Notably, on multivariable Cox regression, the number of days with TTFields adherence of more than 23 hours was independently associated with overall survival (HR 0.96, 95% confidence interval 0.93 - 0.99, p=0.008).

Conclusion

The PriCoTTF trial met its primary endpoint indicating that combined TTFields and radiotherapy is safe and well tolerated. High-grade skin toxicity was quite uncommon and the patients with high TTFields adherence seem to perform particularly well. An extended follow-up is required to provide first estimates regarding putative efficacy. At that point in time, the reduced overall TTFields duration and fraction of patients with GTR need to be factored in.

P11.14.A Systematic review of phase III trials in newly diagnosed glioblastoma 2005-2021

Background

Despite a plethora of studies since the EORTC/NCIC trial in 2005, glioblastoma (GBM) prognosis remains poor. We here identify and compare glioblastoma phase III trials in terms of efficacy and baseline characteristics in an attempt to summarize the experience of the past 16 years.

Methods

A systematic literature search using PubMed and ClinicalTrials.gov was conducted to provide an overview of clinically relevant GBM phase III trials (years 2005-2021) of adult patients younger than 70 years of age. Search results were screened according to predefined inclusion criteria and either excluded or included in further analysis on study design, baseline characteristics, and survival results.

Results

Eleven trials from the literature and clinical trial database fulfilled the search criteria. Among these trials, a total of three GBM phase III trials reported overall survival (OS) benefit, including the EORTC/NCIC study (NCT00006353), EF-14 (NCT00916409) and CeTeG/NOA09 (NCT01149109). All three studies demonstrate similar hazard ratios, which translate into risk reduction of about 40%. Furthermore, low toxicity profile and mostly preserved quality of life were attributed to the treatments tested. Looking at the study designs, eight out of eleven trials were open label randomized trials, including all of the positive ones, and only three negative trials employed treatment blinding and a placebo control. Canonical baseline characteristics (extent of resection, age, gender, MGMT promoter methylation status) did not significantly differ between positive and negative trials. IDH mutation status was analyzed in only two trials, each showing a small percentage of IDH-mutant tumors only.

Conclusion

This analysis on GBM phase III trials conducted between 2005 and 2021 revealed that the majority of trials did not show a significant improvement in overall survival. CeTeG/NOA-09 and EF-14 are the only two studies with positive overall survival outcome since the EORTC/NCIC trial in 2005.

P17.04.B Combination of Trofosfamide and Etoposide in Recurrent Glioma

Background

Disease relapse almost inevitably occurs in patients with adult-type diffuse glioma. Standard of care treatment options at tumor relapse are still not well defined. Frequently used drugs for adult-type diffuse glioma recurrence include lomustine (CCNU) and bevacizumab. Few studies indicate that the combination of trofosfamide/etoposide, given their high lipid solubility with good blood-brain barrier penetrance, may be feasible in pediatric glioblastoma patients. In this retrospective analysis, we determined tolerability and feasibility of combined trofosfamide/etoposide treatment at disease recurrence of patients with adult-type diffuse glioma.

Material and Methods

We collected clinicopathological data from adult patients with adult-type diffuse glioma treated with the combination of trofosfamide/etoposide at the Division of Clinical Neurooncology at the University Hospital Essen. Only those patients were considered eligible who received trofosfamide/etoposide treatment for more than four weeks (one course). Trofosfamide (100mg/m2/day) and Etoposide (25mg/m2/day) was administered orally in a “one week on, one week off” scheme. A cohort of patients receiving empiric treatment at the investigators’ discretion balanced for tumor entity and canonical prognostic factors (number of previous treatments, MGMT promoter methylation, IDH mutation status, KPS, age, extent of resection) served as control. We collected toxicity data as it pertained to CTCAE (Common Terminology Criteria for Adverse Events, version 5.0) and survival data to explore putative efficacy.

Results

A total of 33 patients were eligible for this analysis. In the IDH wild-type glioblastoma (n=18) subgroup, median progression-free survival (3.8 months versus 2.9 months, HR: 2.09, 95% CI: 1.010-4.312, p=0.0227; PFS-6: 39% versus 6%) and median overall survival (10.4 months versus 5.7 months, HR: 3.05, 95% CI: 1.393-6.655, p=0.0008) were significantly prolonged as compared to the control cohort. In a multivariable Cox regression analysis, treatment with trofosfamide/etoposide emerged as statistically significant prognostic marker regarding progression-free survival and overall survival. We observed high-grade adverse events (CTCAE grade≥III ) in 21 (64%) of all recurrent glioma patients with hematotoxicity comprising most adverse events (n=18, 86%). Lymphopenia was by far the most observed hematotoxic adverse event (n=13, 62%). Among non-hematologic high-grade adverse events was transaminase elevation (n=3, 14%).

Conclusion

This study provides first indication that the combination of trofosfamide/etoposide is safe in patients with adult-type diffuse gliomas and may be associated with prolonged survival in adult patients with recurrent IDH wildtype glioblastoma. Our data provide a reasonable rationale for follow-up of a larger cohort in a prospective controlled trial.

OUP accepted manuscript

Analyses of alterations of brain networks have gained an increasing interest in stroke rehabilitation research. Compared with functional networks derived from resting-state analyses, there is limited knowledge of how structural network topology might undergo changes after stroke and, more importantly, if structural network information obtained early after stroke could enhance recovery models to infer later outcomes. The present work re-analysed cross-sectional structural imaging data, obtained within the first 2 weeks, of 45 acute stroke patients (22 females, 24 right-sided strokes, age 68 ± 13 years). Whole-brain tractography was performed to reconstruct structural connectomes and graph-theoretical analyses were employed to quantify global network organization with a focus on parameters of network integration and modular processing. Graph measures were compared between stroke patients and 34 healthy controls (15 females, aged 69 ± 10 years) and they were integrated with four clinical scores of the late subacute stage, covering neurological symptom burden (National Institutes of Health Stroke Scale), global disability (modified Rankin Scale), activity-related disability (Barthel Index) and motor functions (Upper-Extremity Score of the Fugl-Meyer Assessment). The analyses were employed across the complete cohort and, based on clustering analysis, separately within subgroups stratified in mild to moderate (n = 21) and severe (n = 24) initial deficits. The main findings were (i) a significant reduction of network’s global efficiency, specifically in patients with severe deficits compared with controls (P = 0.010) and (ii) a significant negative correlation of network efficiency with the extent of persistent functional deficits at follow-up after 3–6 months (P ≤ 0.032). Specifically, regression models revealed that this measure was capable to increase the explained variance in future deficits by 18% for the modified Rankin Scale, up to 24% for National Institutes of Health Stroke Scale, and 16% for Barthel Index when compared with models including the initial deficits and the lesion volume. Patients with mild to moderate deficits did not exhibit a similar impact of network efficiency on outcome inference. Clustering coefficient and modularity, measures of segregation and modular processing, did not exhibit comparable structure–outcome relationships, neither in severely nor in mildly affected patients. This study provides empirical evidence that structural network efficiency as a graph-theoretical marker of large-scale network topology, quantified early after stroke, relates to recovery. Notably, this contribution was only evident in severely but not mildly affected stroke patients. This suggests that the initial clinical deficit might shape the dependency of recovery on global network topology after stroke.

Crossmodal Pattern Discrimination in Humans and Robots: A Visuo-Tactile Case Study

The quality of crossmodal perception hinges on two factors: The accuracy of the independent unimodal perception and the ability to integrate information from different sensory systems. In humans, the ability for cognitively demanding crossmodal perception diminishes from young to old age. Here, we propose a new approach to research to which degree the different factors contribute to crossmodal processing and the age-related decline by replicating a medical study on visuo-tactile crossmodal pattern discrimination utilizing state-of-the-art tactile sensing technology and artificial neural networks (ANN). We implemented two ANN models to specifically focus on the relevance of early integration of sensory information during the crossmodal processing stream as a mechanism proposed for efficient processing in the human brain. Applying an adaptive staircase procedure, we approached comparable unimodal classification performance for both modalities in the human participants as well as the ANN. This allowed us to compare crossmodal performance between and within the systems, independent of the underlying unimodal processes. Our data show that unimodal classification accuracies of the tactile sensing technology are comparable to humans. For crossmodal discrimination of the ANN the integration of high-level unimodal features on earlier stages of the crossmodal processing stream shows higher accuracies compared to the late integration of independent unimodal classifications. In comparison to humans, the ANN show higher accuracies than older participants in the unimodal as well as the crossmodal condition, but lower accuracies than younger participants in the crossmodal task. Taken together, we can show that state-of-the-art tactile sensing technology is able to perform a complex tactile recognition task at levels comparable to humans. For crossmodal processing, human inspired early sensory integration seems to improve the performance of artificial neural networks. Still, younger participants seem to employ more efficient crossmodal integration mechanisms than modeled in the proposed ANN. Our work demonstrates how collaborative research in neuroscience and embodied artificial neurocognitive models can help to derive models to inform the design of future neurocomputational architectures.

Low-Frequency Brain Oscillations Track Motor Recovery in Human Stroke

OBJECTIVE

The majority of patients with stroke survive the acute episode and live with enduring disability. Effective therapies to support recovery of motor function after stroke are yet to be developed. Key to this development is the identification of neurophysiologic signals that mark recovery and are suitable and susceptible to interventional therapies. Movement preparatory low-frequency oscillations (LFOs) play a key role in cortical control of movement. Recent animal data point to a mechanistic role of motor cortical LFOs in stroke motor deficits and demonstrate neuromodulation intervention with therapeutic benefit. Their relevance in human stroke pathophysiology is unknown.

METHODS

We studied the relationship between movement-preparatory LFOs during the performance of a visuomotor grip task and motor function in a longitudinal (<5 days, 1 and 3 months) cohort study of 33 patients with motor stroke and in 19 healthy volunteers.

RESULTS

Acute stroke-lesioned brains fail to generate the LFO signal. Whereas in healthy humans, a transient occurrence of LFOs preceded movement onset at predominantly contralateral frontoparietal motor regions, recordings in patients revealed that movement-preparatory LFOs were substantially diminished to a level of 38% after acute stroke. LFOs progressively increased at 1 and 3 months. This re-emergence closely tracked the recovery of motor function across several movement qualities including grip strength, fine motor skills, and synergies and was frequency band specific.

INTERPRETATION

Our results provide the first human evidence for a link between movement-preparatory LFOs and functional recovery after stroke, promoting their relevance for movement control. These results suggest that it may be interesting to explore targeted, LFOs-restorative brain stimulation therapy in human stroke patients. ANN NEUROL 2019;86:853-865.

Parietofrontal network upregulation after motor stroke

Objective

Motor recovery after stroke shows a high inter-subject variability. The brain's potential to form new connections determines individual levels of recovery of motor function. Most of our daily activities require visuomotor integration, which engages parietal areas. Compared to the frontal motor system, less is known about the parietal motor system's reconfiguration related to stroke recovery. Here, we tested if functional connectivity among parietal and frontal motor areas undergoes plastic changes after stroke and assessed the behavioral relevance for motor function after stroke.

Methods

We investigated stroke lesion-induced changes in functional connectivity by measuring high-density electroencephalography (EEG) and assessing task-related changes in coherence during a visually guided grip task with the paretic hand in 30 chronic stroke patients with variable motor deficits and 19 healthy control subjects. Quantitative changes in task-related coherence in sensorimotor rhythms were compared to the residual motor deficit.

Results

Parietofrontal coupling was significantly stronger in patients compared to controls. Whereas motor network coupling generally increased during the task in both groups, the task-related coherence between the parietal and primary motor cortex in the stroke lesioned hemisphere showed increased connectivity across a broad range of sensorimotor rhythms. Particularly the parietofrontal task-induced coupling pattern was significantly and positively related to residual impairment in the Nine-Hole Peg Test performance and grip force.

Interpretation

These results demonstrate that parietofrontal motor system integration during visually guided movements is stronger in the stroke-lesioned brain. The correlation with the residual motor deficit could either indicate an unspecific marker of motor network damage or it might indicate that upregulated parietofrontal connectivity has some impact on post-stroke motor function.

Evolution of brain activation after stroke in a constant-effort versus constant-output motor task

PURPOSE

Recovery of hand function after stroke has been associated with transient overactivation of the cerebral sensorimotor network. One open question has been as to how much this transient overactivation is related to 'true' reorganisation of the network or reflecting the fact that a simple motor task is difficult to perform for a patient with a motor deficit, i.e. reflecting 'effort'.

METHODS

To address this, we combined a constant-output (varying effort) and constant-effort (varying output) task in a longitudinal (T1 = 3-5 days, T2 = 6 weeks, T3 = 3 months after stroke) multimodal (functional magnetic resonance imaging (FMRI), electroencephalography (EEG)) study of 12 (EEG)/8 (FMRI) patients (7 male, age 67 ± 9 years) showing significant recovery from a hand motor deficit.

RESULTS

The reduction of sensorimotor activation from T1 to T3 was significant (p = 0.012). But task effort did not exhibit any significant impact on the evolution of task-related brain activation over time. This proved to be equally applicable to FMRI and EEG data.

CONCLUSION

We conclude that initial up-regulation of brain activity after stroke is not simply a consequence of enhanced effort early after stroke but rather reflects neural processes involved in reorganisation and recovery of function.

Concurrent outbreaks of Salmonella Typhimurium in South Australia

The Communicable Disease Control Branch of the South Australian Health Commission received 45 laboratory notifications of Salmonella between 23 December 1996 and 17 January 1997. A rapid screening test, undertaken by the Institute of Medical and Veterinary Sciences, Adelaide, was the first indication that this was more than one outbreak, prompting the establishment of separate investigations. Three Salmonella Typhimurium (S. Typhimurium) phage types were subsequently identified. Investigations are continuing into an outbreak of S. Typhimurium phage type (PT) 64, while investigations failed to identify any association between four cases of PT 44. As of 12 February 1997, 71 notifications had been confirmed as S. Typhimurium PT 135. Epidemiological investigations found this outbreak was associated with consumption of bread rolls with a meat filling distributed through local Asian grocery stores from a home-based manufacturer. The product was voluntarily withdrawn and there have been no new cases of PT 135.

Epidemiological characteristics of Legionella infection in South Australia: implications for disease control

About one third of adults surveyed in South Australia have shown evidence of past silent infection with Legionella pneumophila serogroup 1. However, the annual notification rate for symptomatic disease is only about 0.5 per 100,000 residents in non-epidemic years. The male to female ratio is 2.5 to one and approximately 50% of the cases are at least 60 years of age. Cases have presented more in summer and in the metropolitan areas. Twenty cases of Legionnaires' disease occurred during the summer of 1985-86. A cooling tower was held to be the principal source with aerosols being dispersed up to three kilometers away during an atmospheric thermal inversion. A subsequent outbreak of 22 L. longbeachae serogroup 1 infections had no marked geographic clustering. The outbreak commenced in spring and cases were distinguished as active gardeners. L. longbeachae was found in garden soil and it is hypothesised that this soil inhabitant can become aerosolised and inhaled during gardening. The potential for primary prevention of Legionnaires' disease is discussed in relation to water-handling equipment and the need for early precautionary treatment of all community-acquired pneumonia as suspect Legionnaires' disease is emphasised.