Calcium imaging is a versatile experimental approach capable of resolving single neurons with single-cell spatial resolution in the brain. Electrophysiological recordings provide high temporal, but limited spatial resolution, because of the geometrical inaccessibility of the brain. An approach that integrates the advantages of both techniques could provide new insights into functions of neural circuits. Here, we report a transparent, flexible neural electrode technology based on graphene, which enables simultaneous optical imaging and electrophysiological recording. We demonstrate that hippocampal slices can be imaged through transparent graphene electrodes by both confocal and two-photon microscopy without causing any light-induced artefacts in the electrical recordings. Graphene electrodes record high-frequency bursting activity and slow synaptic potentials that are hard to resolve by multicellular calcium imaging. This transparent electrode technology may pave the way for high spatio-temporal resolution electro-optic mapping of the dynamic neuronal activity.

To determine the effect of frailty on Health Related Quality of Life (HRQoL) after treatment for Head and Neck Cancer (HNC). Patients were prospectively included in OncoLifeS, a data-biobank. Before treatment, patients underwent geriatric screening, including the Groningen Frailty Indicator (GFI) and Geriatric 8 (G8). Patients' HRQoL was measured using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC-QLQ-C30) at three, six, twelve and twenty four months after treatment. Linear mixed models were used for statistical analysis. All models were adjusted for baseline HRQoL values, relevant confounders at baseline and yielded estimates (β), 95% confidence intervals and p-values. 288 patients were included. The mean age was 68.4 years and 68.8% were male. During follow-up, 84 patients had tumor recurrence and 66 died. Response to EORTC-QLQ-C30 ranged from 77.3% to 87.8%. Frail patients, defined by GFI, had significantly worse Global Health Status/Quality of Life (GHS/QoL) (β = -8.70(-13.54;-3.86), p < 0.001), physical functioning (β = -4.55(-8.70;-0.40), p < 0.032), emotional functioning (β = -20.06(-25.65;-15.86), p < 0.001), and social functioning (β = -8.44(-13.91;-2.98), p < 0.003) three months after treatment compared to non-frail patients. Furthermore, frail patients had a significantly worse course of GHS/QoL (β = -7.47(-11.23;-3.70), p = 0.001), physical functioning (β = -3.28(-6.26;-0.31), p = 0.031) and role functioning (β = -7.27(-12.26;-2.28), p = 0.005) over time, compared to non-frail patients. When frailty was determined by G8, frailty was significantly associated with worse GHS/QoL (β = -6.68(-11.00;-2.37), p = 0.003) and emotional functioning (β = -5.08(-9.43;-0.73), p = 0.022) three months after treatment. Frail patients are at increased risk for decline in HRQoL, and further deterioration during follow-up after treatment for HNC.

Objective: We aimed to compare frailty status between patients with head and neck cancer (HNC) and other solid malignancies.Methods: Data collection was prospective, and the following were compared between cohorts at baseline: patient and tumour characteristics, Charlson Comorbidity Index (CCI), Groningen Frailty Indicator (GFI), Mini Mental State Examination (MMSE), Activities of Daily Living (ADLs), Instrumental ADLs (IADLs), Timed Up and Go (TUG) and Quality of Life (QoL). Univariate and multivariate logistic regression analyses were performed, and odds ratios (ORs) with their 95% confidence intervals (95% CIs) were estimated.Results: In total, 242 patients with HNC and 180 with other oncology diagnoses were enrolled, of whom 32.6% and 21.8% were frail according to the GFI respectively. Comorbidity scores were not significantly different between the cohorts (7.4% vs. 13.1%; OR 0.54; 95% CI 0.28–1.02). In the univariate analysis, the GFI was significantly worse in the HNC cohort (OR 1.74; 95% CI 1.11–2.71). However, in the multivariate analysis, the MMSE, TUG and global QoL were significantly worse in the HNC cohort, with ORs of 20.03 (95% CI 2.44–164.31), 11.56 (95% CI 1.86–71.68) and 0.98 (95% CI 0.97–1.00) respectively.Conclusion: Patients with HNC appear to be frailer than patients with other solid malignancies despite comparable levels of comorbidity.

We aimed to evaluate the association between frailty screening and geriatric assessment (GA) on short term adverse events in patients treated for head and neck cancer (HNC) for the first time in a prospective study. Newly diagnosed HNC patients undergoing curative treatment were prospectively included in OncoLifeS, a data biobank. Prior to the start of treatment, frailty was assessed with a GA, Groningen Frailty Indicator (GFI) and Geriatric-8 (G8). The GA included comorbidity (Adult Comorbidity Evaluation - 27), nutritional status (Malnutrition Universal Screening Tool), functional status ((instrumental) Activities of Daily Living), mobility (Timed Up & Go), psychological (Geriatric Depression Scale 15) and cognitive (Mini Mental State Examination) measures. Clinically relevant postoperative complications (Clavien-Dindo ≥ grade 2) and acute radiation-induced toxicity (Common Terminology Criteria for Adverse Events version 4.0 ≥ grade 2) were defined as outcome measures. Univariable and multivariable logistic regression analyses were performed, yielding odds ratios (ORs) and 95% confidence intervals (95%CIs). Of the 369 included patients, 259 patients were eligible for analysis. Postoperative complications occurred in 41/148 (27.7%) patients and acute radiation-induced toxicity was present in 86/160 (53.7%) patients. Number of deficit domains of GA (OR = 1.71, 95%CI = 1.14-2.56), GFI (OR = 2.54, 95%CI = 1.02-6.31) and G8 (OR5.59, 95%CI = 2.14-14.60) were associated with postoperative complications, but not with radiation-induced toxicity. Frailty and restrictions in geriatric domains were associated with postoperative complications, but not with radiation-induced acute toxicity in curatively treated HNC patients. The results of this prospective study further emphasizes the importance of geriatric evaluation, particularly before surgery.

Geriatric impairments and frailty are highly prevalent in patients with head and neck cancer (HNC). This study investigated the association of frailty and outcomes of geriatric assessment (GA) with radiation-induced toxicity (RIT) in patients undergoing (chemo)radiotherapy ((C)RT) for HNC. Between October 2014 and April 2016, patients with HNC were prospectively included in OncoLifeS, an institutional data-biobank. Before treatment initiation, patients underwent GA and frailty screening (Groningen Frailty Indicator and Geriatric 8). The main outcome of this study was RIT (weight loss, mucositis, salivary gland inflammation, oral pain, sore throat, hoarseness, dry mouth, dysgeusia, dysphagia and general pain) according to the common terminology criteria of adverse events (CTCAE) version 4.0. Linear mixed models were performed, to analyse factors associated with increasing mean RIT over time during the treatment period. 160 patients were included. 114 (71.3%) were male and the mean age was 66.1 years. Age ≥ 65 (β = 0.03(95 %CI = 0.01;0.05), p = 0.01), regional RT (β = 0.05(95 %CI = 0.02;0.09), p = 0.004), and concurrent chemotherapy (β = 0.04(95 %CI = 0.02;0.07), p = 0.001), were independent factors associated with increasing toxicity during the 7-week treatment period, adjusted for relevant covariates. None of the single items of GA, as well as the frailty screening instruments, were associated with increasing RIT. In this study, frailty and GA were not associated with additional RIT during treatment. These results suggest that (C)RT is equally tolerated in frail and non-frail patients, with respect to acute RIT. RT could be a suitable alternative to surgery in selected frail patients.