Surprise-minimization as a solution to the structural credit assignment problem.

The structural credit assignment problem arises when the causal structure between actions and subsequent outcomes is hidden from direct observation. To solve this problem and enable goal-directed behavior, an agent has to infer structure and form a representation thereof. In the scope of this study, we investigate a possible solution in the human brain. We recorded behavioral and electrophysiological data from human participants in a novel variant of the bandit task, where multiple actions lead to multiple outcomes. Crucially, the mapping between actions and outcomes was hidden and not instructed to the participants. Human choice behavior revealed clear hallmarks of credit assignment and learning. Moreover, a computational model which formalizes action selection as the competition between multiple representations of the hidden structure was fit to account for participants data. Starting in a state of uncertainty about the correct representation, the central mechanism of this model is the arbitration of action control towards the representation which minimizes surprise about outcomes. Crucially, single-trial latent-variable analysis reveals that the neural patterns clearly support central quantitative predictions of this surprise minimization model. The results suggest that neural activity is not only related to reinforcement learning under correct as well as incorrect task representations but also reflects central mechanisms of credit assignment and behavioral arbitration.

[Enhanced quality of documentation for biologic therapy of chronic rhinosinusitis through structured digital reporting and indication?] / Qualitätssteigerung der Dokumentation zur Biologikatherapie der chronischen Rhinosinusitis durch digitale, strukturierte Befunderhebung und Indikationsstellung?

BACKGROUND: With targeted inhibition of type 2 inflammation, biologics represent the standard add-on therapy for inadequately controlled severe forms of chronic rhinosinusitis with nasal polyps (CRSwNP). Despite standardization with paper-based checklists, the documentation of medical history and current findings pertinent to indication criteria are a significant challenge for physicians. Through development of an application based on structured reporting, the current study aimed to improve documentation quality and simplify the decision-making process. Previously available paper checklists served as a comparison. METHODS: For this study, a digital incremental tool was programmed to record current findings and check for fulfilment of indication criteria. The tool was compared with other checklists in terms of completeness, time required, and readability. RESULTS: A total of 20 findings were collected for each of the three documentation options and included in the analysis. Documentation with the two paper-based checklists had comparable information content: 17.5 ± 5.1/21.7 ± 7.6 points out of a maximum of 43 points; p > 0.05. Documentation using the digital application led to a significant increase in information content compared to all paper-based documentation. The average score was 38.25 ± 3.7 (88.9% of maximum; p < 0.001). On average, user satisfaction was high (9.6/10). Use of the digital application was initially more time consuming, but as more cases were documented, the time taken improved significantly. CONCLUSION: In the future, structured reporting using apps could replace paper-based reporting for the indication of biologic therapy in CRSwNP patients and offer additional benefits in terms of data quality and traceability of results. The increasing volume of documentation in the future, the progress of digitalization, and the possibility of networking between individual centers make introduction of the app in the near future both likely and economical.

[Results of a survey on the current management of chronic rhinosinusitis with nasal polyps in Germany]. / Ergebnisse einer Umfrage zur aktuellen Behandlung der chronischen Rhinosinusitis mit nasalen Polypen.

INTRODUCTION: With a prevalence of 0.55% to 4%, chronic rhinosinusitis with nasal polyps (CRSwNP) is a relevant part of the daily work of German otolaryngologists. The aim of the questionnaire-based data collection was to assess the current treatment status of CRSwNP in Germany. MATERIAL AND METHODS: For this purpose, 24 questions within an anonymized online questionnaire were sent to all German ENT departments. RESULTS: Of 160 contacted ENT departments, 50 participated in the survey (31.3%). Among these, 76% performed more than 100 sinus surgeries annually and 38% treated more than 50 patients with biologics. Saline irrigations (80%) and intranasal glucocorticoids (GCS, 96%) were the most common conservative therapies. Systemic GCSs (52%) and intranasal GCS irrigation (20%) were less common. 80% of departments used biologics in the therapy of CRSwNP with an overall preference for dupilumab (70%). For therapy of aspirin intolerance, biologics (52%) were preferred to aspirin desensitization (26%). Prior to treatment with biologics clinical workup included the nasal polyp score (90%), the SNOT-22 questionnaire (84%), surrogate markers of type 2 inflammation (60%-72%), and computer tomography (50%). Final treatment success was assessed after 24 weeks (50%). CONCLUSION: Mostly, the responding departments followed German and European recommendations for diagnosis and therapy of CRSwNP. Therapy with biologics is widely used. The value of preoperative systemic GCS and the frequent performance of CT before initiation of therapy with a biologic should be debated in regard to its currently widespread use.

[Nodal metastasis and value of neck dissection in T1/2 oropharyngeal and hypopharyngeal carcinomas]. / Nodale Metastasierung und Stellenwert der Neck Dissection bei T1/2-Oro- und Hypopharynxkarzinomen.

BACKGROUND: Due to heterogeneous data, the indication for elective neck dissection (END) in patients with squamous cell carcinoma of the hypopharynx and oropharynx (HPSCC and OPSCC) in stages T1/2N0 is somewhat unclear. Therefore, in this multicenter study, we performed detailed analysis of the metastatic behavior of HPSCC and OPSCC. MATERIAL AND METHODS: The nodal metastatic patterns of 262 HPSCC and OPSCC patients who had undergone surgery was retrospectively investigated. In addition, recurrence-free and overall survival were recorded. Furthermore, a systematic literature review on the topic was completed. RESULTS: In patients with HPSCC, a discrepancy between clinical and pathologic N status was recorded in 62.1% of patients vs. 52.4% for p16- OPSCC, and 43.6% for p16+ OPSCC. The occult metastasis rate in cT1/2cN0 primary tumors was 38.9% for HPSCC vs. 17.8% (p16- OPSCC) and 11.1% (p16+ OPSCC). Contralateral metastases occurred in 22.2% of cases for HPSCC at stages cT1/2cN0, compared to only 9.1% for p16- OPSCC, and 0% for p16+ OPSCC patients.Patients with p16+ OPSCC had better recurrence-free and overall survival than p16- OPSCC and HPSCC patients. A direct association between patient survival and the extent of neck surgical therapy could not be demonstrated in our patients. CONCLUSION: Patients with HPSCC are at risk for bilateral neck metastases from stage cT1/2cN0, justifying bilateral END. Patients with T1/2 OPSCC present with occult metastases ipsilaterally in >20% of cases; however, the risk for contralateral occult metastasis is <10%. Hence, in strictly lateralized cT1/2CN0 tumors, omission of contralateral END may be considered.

The German hearing in noise test with a female talker: development and comparison with German male speech test.

PURPOSE: The aim of the study was to develop the German Hearing in Noise Test (HINT) with female speaker by fulfilling the recommendations by International Collegium of Rehabilitative Audiology (ICRA) for using a female speaker to create new multilingual speech tests and to determine norms and to compare these norms with German male speech tests-the male speakers HINT and the Oldenburg Sentence Test (OLSA). METHODS: The HINT with a female speaker consists of the same speech material as the male speaking HINT. After recording the speech material, 10 normal hearing subjects were included to determine the performance-intensity function (PI function). 24 subjects were part of the measurements to determine the norms and compare them with the norms of male HINT and OLSA. Comparably, adaptive, open-set methods under headphones (HINT) and sound field (OLSA) were used. RESULTS: Acoustic phonetic analysis demonstrated significant difference in mean fundamental frequency, its range and mean speaking rate between both HINT speakers. The calculated norms by three of the tested four conditions of the HINT with a female speaker are not significantly different from the norms with a male speaker. No significant effect of the speaker's gender of the first HINT measurement and no significant correlation between the threshold results of the HINT and the OLSA were determined. CONCLUSIONS: The Norms for German HINT with a female speaker are comparable to the norms of the HINT with a male speaker. The speech intelligibility score of the HINT does not depend on the speakers' gender despite significant difference of acoustic-phonetic parameters between the female and male HINT speaker's voice. Instead, the speech intelligibility rating must be seen as a function of the used speech material.

Hearing rehabilitation for unilateral deafness using a cochlear implant: the influence of the subjective duration of deafness on speech intelligibility.

BACKGROUND: For patients with single sided deafness (SSD) or severe asymmetric sensorineural hearing loss (ASHL), cochlear implantation remains the only solution to restore bilateral hearing capacity. Prognostically, the duration of hearing loss in terms of audiological outcome is not yet clear. Therefore, the aim of this study was to retrospectively investigate the influence of subjective deafness duration on postoperative speech perception after cochlear implantation for SSD as well as its impact on quality of life. MATERIALS AND METHODS: The present study included a total of 36 adults aged 50.2 ± 15.5 years who underwent CI for SSD/ASHL at our clinic between 2010 and 2015. Patients were audiometrically assessed at 3 and 12-36 months postoperatively. Test results were correlated with self-reported duration of deafness. Quality of life was assessed by questionnaire. RESULTS: Mean duration of deafness was 193.9 ± 185.7 months. The side-separated hearing threshold showed an averaged target range between 30 and 40 dB HL. Freiburg monosyllable test increased from 0% pre-operatively to 20% after 3 months (p = 0.001) and to 50% after 12-36 months (p = 0.002). There was a significant correlation between audiometric outcome and subjective deafness duration at 12-36 months postoperatively (r = - 0.564; p = 0.02) with a cutoff for open-set monosyllable recognition at a duration of deafness of greater than 408 months. Quality of life was significantly improved by CI. CONCLUSIONS: CI implantation in unilaterally deafened patients provides objective and subjective benefits. Duration of deafness is unlikely to be an independent negative predictive factor and thus should not generally be considered as contraindication.

Task Learnability Modulates Surprise but Not Valence Processing for Reinforcement Learning in Probabilistic Choice Tasks.

The goal of temporal difference (TD) reinforcement learning is to maximize outcomes and improve future decision-making. It does so by utilizing a prediction error (PE), which quantifies the difference between the expected and the obtained outcome. In gambling tasks, however, decision-making cannot be improved because of the lack of learnability. On the basis of the idea that TD utilizes two independent bits of information from the PE (valence and surprise), we asked which of these aspects is affected when a task is not learnable. We contrasted behavioral data and ERPs in a learning variant and a gambling variant of a simple two-armed bandit task, in which outcome sequences were matched across tasks. Participants were explicitly informed that feedback could be used to improve performance in the learning task but not in the gambling task, and we predicted a corresponding modulation of the aspects of the PE. We used a model-based analysis of ERP data to extract the neural footprints of the valence and surprise information in the two tasks. Our results revealed that task learnability modulates reinforcement learning via the suppression of surprise processing but leaves the processing of valence unaffected. On the basis of our model and the data, we propose that task learnability can selectively suppress TD learning as well as alter behavioral adaptation based on a flexible cost-benefit arbitration.

Comparison of Magnetic Resonance Imaging and Contrast-Enhanced Ultrasound as Diagnostic Options for Unclear Cystic Renal Lesions: A Cost-Effectiveness Analysis.

PURPOSE: Correct differentiation between malignant and benign incidentally found cystic renal lesions has critical implications for patient management. In several studies contrast-enhanced ultrasound (CEUS) showed higher sensitivity with respect to the accurate characterization of these lesions compared to MRI, but the cost-effectiveness of CEUS has yet to be investigated. The aim of this study was to analyze the cost-effectiveness of CEUS as an alternative imaging method to MRI for the characterization of incidentally found cystic renal lesions. MATERIALS AND METHODS: A decision model including the diagnostic modalities MRI and CEUS was created based on Markov simulations estimating lifetime costs and quality-adjusted life years (QALYs). The recent literature was reviewed to obtain model input parameters. The deterministic sensitivity of diagnostic parameters and costs was determined and probabilistic sensitivity analysis using Monte-Carlo Modelling was applied. Willingness-to-pay (WTP) was assumed to be $ 100 000/QALY. RESULTS: In the base-case scenario, the total costs for CEUS were $9654.43, whereas the total costs for MRI were $9675.03. CEUS resulted in an expected effectiveness of 8.06 QALYs versus 8.06 QALYs for MRI. Therefore, from an economic point of view, CEUS was identified as an adequate diagnostic alternative to MRI. Sensitivity analysis showed that results may vary if CEUS costs increase or those of MRI decrease. CONCLUSION: Based on the results of the analysis, the use of CEUS was identified as a cost-effective diagnostic strategy for the characterization of incidentally found cystic renal lesions.

[Cost minimization analysis of flexible ENT-endoscopes]. / Kostenvergleichsanalyse von flexiblen HNO-Endoskopen.

BACKGROUND: Reprocessing of complex instruments like flexible ENT-endoscopes with and without working channel are challanging for clinics and private practices. Aim of the study was to analyse the costs of an examination with a reusable endoscope-system and to compare it with two single-use endoscope-systems. MATERIAL AND METHODS: A cost minimization analysis was performed at the Department of Otorhinolaryngology, Head and Neck Surgery of the University Medical Center in Mainz, Germany. The local reusable endoscopy-system was compared with two single-use endoscopy-systems of Ambu and Karl Storz. RESULTS: Overall costs per examination with a reusable-scope were 23.03 € (11.60 € investment costs + 5.09 € repair costs + 6.34 € reprocessing costs). The single-use Endoscopy-system of Ambu resulted in 120.43 € per examination (120.00 € acquisition costs + 0.43 € storage costs). Overall costs for the single-use endoscopy-system of Karl Storz were 223.44 € per examination (investment costs for monitors 3.01 € + 220.00 € acquisition costs + 0.43 € storage costs). DISCUSSION: Flexible single-use ENT-endoscopy-systems generate higher costs in comparison to conventional reusable ones. But there are also advantages from the medical and economical side. CONCLUSION: A smart mix of reusable and single-use endoscopy systems seems therefore usefull.

[Cervicofacial actinomycosis]. / Zervikofaziale Aktinomykose.

Actinomycosis is an infectious disease caused by gram-positive, facultative anaerobic bacteria, which in most cases manifests itself in the cervicofacial area and often has a dentogenic focus. The clinical presentation ranges from acute abscess to chronically fistulating soft tissue processes. Early diagnosis and an appropriate therapeutic approach including a combination of extensive antibiotic treatment and, if necessary, surgical intervention are critical. This article presents five cases of actinomycete infections, which are intended to illustrate the variety of clinical presentations, the problems on the way to the correct diagnosis and possible therapeutic courses.

ENT Residents Benefit from a Structured Operation Planning Approach in the Training of Functional Endoscopic Sinus Surgery.

Background and Objectives: Preoperative planning utilizing computed tomographies (CT) is of utmost importance in functional endoscopic sinus surgery (FESS). Frequently, no uniform documentation and planning structures are available to residents in training. Consequently, overall completeness and quality of operation planning may vary greatly. The objective of the present study was to evaluate the impact of a structured operation planning (SOP) approach on the report quality and user convenience during a 4-day sinus surgery course. Materials and Methods: Fifteen participant were requested to plan a FESS procedure based on a CT scan of the paranasal sinuses that exhibited common pathological features, in a conventional manner, using a free text. Afterwards, the participants reevaluated the same scans by means of a specifically designed structured reporting template. Two experienced ENT surgeons assessed the collected conventional operation planning (COP) and SOP methods independently with regard to time requirements, overall quality, and legibility. User convenience data were collected by utilizing visual analogue scales. Results: A significantly greater time expenditure was associated with SOPs (183 s vs. 297 s, p = 0.0003). Yet, legibility (100% vs. 72%, p < 0.0001) and overall completeness (61.3% vs. 22.7%, p < 0.0001) of SOPs was significantly superior to COPs. Additionally, description of highly relevant variants in anatomy and pathologies were outlined in greater detail. User convenience data delineated a significant preference for SOPs (VAS 7.9 vs. 6.9, p = 0.0185). Conclusions: CT-based planning of FESS procedures by residents in training using a structured approach is more time-consuming while producing a superior report quality in terms of detailedness and readability. Consequently, SOP can be considered as a valuable tool in the process of preoperative evaluations, especially within residency.

The influence of internal models on feedback-related brain activity.

Decision making relies on the interplay between two distinct learning mechanisms, namely habitual model-free learning and goal-directed model-based learning. Recent literature suggests that this interplay is significantly shaped by the environmental structure as represented by an internal model. We employed a modified two-stage but one-decision Markov decision task to investigate how two internal models differing in the predictability of stage transitions influence the neural correlates of feedback processing. Our results demonstrate that fronto-central theta and the feedback-related negativity (FRN), two correlates of reward prediction errors in the medial frontal cortex, are independent of the internal representations of the environmental structure. In contrast, centro-parietal delta and the P3, two correlates possibly reflecting feedback evaluation in working memory, were highly susceptible to the underlying internal model. Model-based analyses of single-trial activity showed a comparable pattern, indicating that while the computation of unsigned reward prediction errors is represented by theta and the FRN irrespective of the internal models, the P3 adapts to the internal representation of an environment. Our findings further substantiate the assumption that the feedback-locked components under investigation reflect distinct mechanisms of feedback processing and that different internal models selectively influence these mechanisms.

The effect of feedback novelty on neural correlates of feedback processing.

It has been suggested that stimulus novelty itself can be rewarding and recent evidence suggests that novelty processing and reward processing share common neural mechanisms. For feedback processing, this can be beneficial as well as detrimental: If novelty lends a rewarding characteristic to a stimulus, then this should particularly decrease the impact of negative feedback. The present study investigated whether such an effect of feedback novelty on feedback processing is reflected in electrophysiological markers of reinforcement learning (feedback-related negativity, FRN) and feedback processing (feedback-P300) in a simple decision-making task. In this task, participants had to chose between two stimuli in a learning trial followed by a novel or a familiar feedback stimulus. Learning from feedback allowed them to optimize their payoff in a later test trial. As expected, we found that the FRN effect, i.e. the difference between the FRN amplitudes after negative and positive feedback, was reduced for novel compared to familiar feedback stimuli. In addition, the amplitude of the feedback-P300 was decreased by feedback novelty, both for the anterior P3a and the posterior P3b. Together, these results indicate that feedback novelty can affect feedback processing as reflected by feedback-related brain activity.

The use of structured reporting of head and neck ultrasound ensures time-efficiency and report quality during residency.

PURPOSE: Free text reports (FTR) of head and neck ultrasound studies are currently deployed in most departments. Because of a lack of composition and language, these reports vary greatly in terms of quality and reliability. This may impair the learning process during residency. The purpose of the study was to analyze the longitudinal effects of using structured reports (SR) of head and neck ultrasound studies during residency. METHODS: Attending residents (n = 24) of a tripartite course on head and neck ultrasound, accredited by the German Society for Ultrasound in Medicine (DEGUM), were randomly allocated to pictures of common diseases. Both SRs and FTRs were compiled. All reports were analyzed concerning completeness, acquired time and legibility. Overall user contentment was evaluated by a questionnaire. RESULTS: SRs achieved significantly higher ratings regarding completeness (95.6% vs. 26.4%, p < 0.001), description of pathologies (72.2% vs. 58.9%, p < 0.001) and legibility (100% vs. 52.4%, p < 0.001) with a very high inter-rater reliability (Fleiss' kappa 0.9). Reports were finalized significantly faster (99.1 s vs. 115.0 s, p < 0.001) and user contentment was significantly better when using SRs (8.3 vs. 6.3, p < 0.001). In particular, only SRs showed a longitudinally increasing time efficiency (- 20.1 s, p = 0.036) while maintaining consistent completeness ratings. CONCLUSIONS: The use of SRs of head and neck ultrasound studies results in an increased longitudinal time-efficiency while upholding the report quality at the same time. This may indicate an additive learning effect of structured reporting. Superior outcomes in terms of comprehensiveness, legibility and time-efficiency can be observed immediately after implementation.

Structured reporting of head and neck ultrasound examinations.

BACKGROUND: Reports of head and neck ultrasound examinations are frequently written by hand as free texts. Naturally, quality and structure of free text reports is variable, depending on the examiner's individual level of experience. Aim of the present study was to compare the quality of free text reports (FTR) and structured reports (SR) of head and neck ultrasound examinations. METHODS: Both standard FTRs and SRs of head and neck ultrasound examinations of 43 patients were acquired by nine independent examiners with comparable levels of experience. A template for structured reporting of head and neck ultrasound examinations was created using a web-based approach. FTRs and SRs were evaluated with regard to overall quality, completeness, required time to completion, and readability by four independent raters with different specializations (Paired Wilcoxon test, 95% CI) and inter-rater reliability was assessed (Fleiss' kappa). A questionnaire was used to compare FTRs vs. SRs with respect to user satisfaction (Mann-Whitney U test, 95% CI). RESULTS: By comparison, completeness scores of SRs were significantly higher than FTRs' completeness scores (94.4% vs. 45.6%, p < 0.001), and pathologies were described in more detail (91.1% vs. 54.5%, p < 0.001). Readability was significantly higher in all SRs when compared to FTRs (100% vs. 47.1%, p < 0.001). The mean time to complete a report, however, was significantly higher in SRs (176.5 vs. 107.3 s, p < 0.001). SRs achieved significantly higher user satisfaction ratings (VAS 8.87 vs. 1.41, p < 0.001) and a very high inter-rater reliability (Fleiss' kappa 0.92). CONCLUSIONS: As compared to FTRs, SRs of head and neck ultrasound examinations are more comprehensive and easier to understand. On the balance, the additional time needed for completing a SR is negligible. Also, SRs yield high inter-rater reliability and may be used for high-quality scientific data analyses.

Contact Lens Versus Non-Contact Lens-Related Corneal Ulcers at an Academic Center.

PURPOSE: To compare the infectious contact lens-related corneal ulcer (CLRU) and non-CLRU cases at Saint Louis University. METHODS: Retrospective review of corneal ulcer cases identified by search of the ophthalmology and microbiology department databases between 1999 and 2016. RESULTS: Six hundred seventy-seven cases of corneal ulcers were identified, of which 46% were CLRU. CLRU cases were seen more commonly in younger patients (P<0.001) and women (P=0.03) than non-CLRU cases. Many of the infections were vision-threatening as defined by central/paracentral location (73% CLRU and 71% non-CLRU [P=0.60]) and large size of ulcer >2 mm in 36% CLRU and 51% non-CLRU (P=0.002). Causative pathogen in cultured CLRU was predominately Pseudomonas species (44%, P<0.001 vs. the non-CLRU group), other gram-negative (6%), gram-positive (33%), fungi (13%), and Acanthamoeba (5%). Comparatively, cultured non-CLRU was predominately gram-positive (64%, P<0.001 vs. the CLRU group), gram-negative (26%), and fungi (11%). The combined oxacillin-resistant Staphylococcus aureus and coagulase-negative Staphylococcus isolates were 35% and 34%, respectively. Despite the progressive increase in the number of corneal ulcers seen, the annual trend for any one particular organism for either CLRU cases or non-CLRU cases did not change significantly. CONCLUSIONS: Most of the cases were non-CLRU. CLRU was disproportionately associated with Pseudomonas species and non-CLRU with Staphylococcal species. Fungal infections were predominately caused by filamentous organisms in both groups. Acanthamoeba keratitis was exclusively associated with CL use.

Impact of structured reporting on developing head and neck ultrasound skills.

BACKGROUND: Reports of head and neck ultrasound examinations are frequently written by hand as free texts. This is a serious obstacle to the learning process of the modality due to a missing report structure and terminology. Therefore, there is a great inter-observer variability in overall report quality. Aim of the present study was to evaluate the impact of structured reporting on the learning process as indicated by the overall report quality of head and neck ultrasound examinations within medical school education. METHODS: Following an immersion course on head and neck ultrasound, previously documented images of three common pathologies were handed out to 58 medical students who asked to create both standard free text reports (FTR) and structured reports (SR). A template for structured reporting of head and neck ultrasound examinations was created using a web-based approach. FTRs and SRs were evaluated with regard to overall quality, completeness, required time to completion and readability by two independent raters (Paired Wilcoxon test, 95% CI). Ratings were assessed for inter-rater reliability (Fleiss' kappa). Additionally, a questionnaire was utilized to evaluate user satisfaction. RESULTS: SRs received significantly better ratings in terms of report completeness (97.7% vs. 53.5%, p < 0.001) regarding all items. In addition, pathologies were described in more detail using SRs (70% vs. 51.1%, p < 0.001). Readability was significantly higher in all SRs when compared to FTRs (100% vs. 54.4%, p < 0.001). Mean time to complete was significantly lower (79.6 vs. 205.4 s, p < 0.001) and user satisfaction was significantly higher when using SRs (8.5 vs. 4.1, p < 0.001). Also, inter-rater reliability was very high (Fleiss' kappa 0.93). CONCLUSIONS: SRs of head and neck ultrasound examinations provide more detailed information with a better readability in a time-saving manner within medical education. Also, medical students may benefit from SRs in their learning process due to the structured approach and standardized terminology.

High-Grade Neuroendocrine Carcinoma of the Head and Neck: Human Papillomavirus Status and PD-L1 Expression.

BACKGROUND: Human papillomavirus (HPV)-related head and neck squamous cell carcinoma represents an important subgroup of head and neck cancer, but HPV occurs also in the less common neuroendocrine carcinomas (NEC). The PD-1/PD-L1 pathway appears to be activated in pulmonary NEC and correlates with a higher mutation burden, but the potential of NEC to respond to checkpoint inhibitors is unknown to a large extent. OBJECTIVES: To determine the HPV status of NEC of the head and neck region and to investigate the expression of PD-1 and its ligands PD-L1 and PD-L2. METHODS: Surgical tumor samples from 2006 to 2017 were analyzed. HPV status was determined by p16 immunohistochemistry (IHC) and multiplex PCR. IHC using the Cologne Score was performed for PD-1, PD-L1, and PD-L2. RESULTS: Seven NEC tumor samples were analyzed, three of them showed HPV type 18. Expression of PD-1 and PD-L1 differed widely and showed no correlation to HPV status. IHC showed an overexpression of PD-L2 in most of the patients. CONCLUSIONS AND SIGNIFICANCE: A multicentric analysis of NEC is needed to further evaluate the role of HPV as well as immunocheckpoints with regard to inflammatory immune response in genesis and clinical course of this rare tumor entity. Biomarkers for selection of novel treatment regimens, including immunotherapeutic approaches, are warranted.

Effects of feedback reliability on feedback-related brain activity: A feedback valuation account.

Adaptive decision making relies on learning from feedback. Because feedback sometimes can be misleading, optimal learning requires that knowledge about the feedback's reliability be utilized to adjust feedback processing. Although previous research has shown that feedback reliability indeed influences feedback processing, the underlying mechanisms through which this is accomplished remain unclear. Here we propose that feedback processing is adjusted by the adaptive, top-down valuation of feedback. We assume that unreliable feedback is devalued relative to reliable feedback, thus reducing the reward prediction errors that underlie feedback-related brain activity and learning. A crucial prediction of this account is that the effects of feedback reliability are susceptible to contrast effects. That is, the effects of feedback reliability should be enhanced when both reliable and unreliable feedback are experienced within the same context, as compared to when only one level of feedback reliability is experienced. To evaluate this prediction, we measured the event-related potentials elicited by feedback in two experiments in which feedback reliability was varied either within or between blocks. We found that the fronto-central valence effect, a correlate of reward prediction errors during reinforcement learning, was reduced for unreliable feedback. But this result was obtained only when feedback reliability was varied within blocks, thus indicating a contrast effect. This suggests that the adaptive valuation of feedback is one mechanism underlying the effects of feedback reliability on feedback processing.