Stefan Röttger

Phase-Locking and Amplitude Modulations of EEG Alpha: Two Measures Reflect Different Cognitive Processes in a Working Memory Task

It has been demonstrated in numerous experiments that oscillatory EEG responses in the alpha frequency band (8-12 Hz) increase with memory load during the retention interval in working memory tasks. However, the findings diverge with respect to which measurement of alpha activity is influenced by memory processes. Here, we differentiate between evoked and total alpha activity in order to separate effects of phase-locking and amplitude modulation. We present data from a delayed-matching-to-sample task (S1-S2 paradigm) for which we compared EEG alpha responses between a perception and a memory condition. Increased total alpha activity was found in the retention interval for the memory as compared to the perception condition. Evoked alpha activity, however, did not differentiate between memory and perception conditions but, instead, was increased for the more complex condition of processing non-Kanizsa figures as compared to Kanizsa figures. Thus, our results demonstrate a functional differentiation between evoked and total alpha activity. While alpha phase locking seemed to be influenced mainly by task complexity, alpha amplitude clearly reflected memory demands in our paradigm.

Selective tuning of cortical sound-feature processing by language experience.

In ‘quantity‐languages’, such as Japanese or Finnish, sound duration is linguistically relevant. We showed that quantity‐language speakers were superior to speakers of a non‐quantity language in discriminating the duration of even non‐speech sounds. In contrast, there was no group difference in the discrimination of sound frequency. This result, obtained both by behavioural and neural indices at attentive and automatic levels of processing, indicates precise feature‐specific tuning of the auditory‐cortex functions by the mother tongue.

Evaluation of a navigation system for ENT with surgical efficiency criteria

The aim of this study is the evaluation of a navigation system (NaviBase) for ENT surgery. For this purpose, a new methodology for the evaluation of surgical and ergonomic system properties has been developed. The practicability of the evaluation instruments will be examined using the example of the overall assessment of the system in comparison with the current surgical standard and with other systems using clinical efficiency criteria. The evaluation is based on 102 ENT surgical applications; of these, 89 were functional endoscopic sinus surgeries (FESS). The evaluation of surgical and ergonomic performance factors was performed by seven ENT surgeons. To evaluate surgical system properties, the Level of Quality (LOQ) in 89 cases of the FESS was determined. It compares the existing information of the surgeon with that of the navigation system on a scale of 0 to 100 and with a mean value of 50 and places it in a relationship to the clinical impact. The intraoperative change of the planned surgical strategy (Change of Surgical Strategy) was documented. The ergonomic factors of the system with the categories of Overall Confidence (Trust), awareness of the situation (Situation Awareness), influence on the operating team, requirements for specific skills (Skill Set Requirement), and cognitive load (Workload Shift) were recorded for all surgical procedures as Level of Reliance (LOR). In the evaluation of the surgical system properties, an average evaluation of the quality of the information, as an LOQ of 63.59, resulted. Every second application of the navigation system (47.9%), on average, led to a change in the surgical strategy. An extension/enhancement of the indication of the endonasal approach through the use of the navigation system was shown in 7 of 102 (6.8%) cases. The completion of the resection in the FESS was rated by 74% of group I and 11% of group II as better in comparison with the standard approach. Total confidence shows a positive evaluation of 3.35 in the LOR. To supplement the evaluation of the navigation system, the technical parameters were included. The maximum deviation, Amax, of the displayed position of the reference value amounted to 1.93 mm. The average deviation was at 1.29 mm with an SD above all values, sd, of 0.29. The subsequent economic evaluation resulted in an effective average extra expenditure of time of 1.35 minutes per case. The overall evaluation of the system imparts application‐relevant information beyond the technical details and permits comparability between different assistance systems.

Kanizsa subjective figures capture visual spatial attention: evidence from electrophysiological and behavioral data

Figural binding and attention are two important processes that help to perceive the outside world. Binding is necessary to link together the different features of single objects which are represented in a distributed fashion in the brain. Attention serves to focus onto a small subset of incoming information. It is still not clear how exactly these two mechanisms operate and interact. We performed two experiments employing illusory Kanizsa figures (KFs) to investigate the temporal order of figural binding and spatial attention. In a visual search task, subjects had to detect the presence of a KF among distractor stimuli. We found only a slight increase of reaction times when increasing the number of distractors, indicating that KFs popped out and drew the perceivers attention. In a further event-related potential (ERP) study, we used displays of the search task as non-informative cue for a subsequent target choice-reaction task. Enhanced contralateral negative amplitudes (starting at about 230 ms) over ventral occipital areas were found for cue displays which included a KF. For target stimuli, faster reaction times and enhanced ipsilateral N1 amplitudes over occipito-parietal areas were observed for validly (target presentation inside a KF) as compared to invalidly cued targets (target presentation outside a KF). Furthermore, enhanced contralateral N1 amplitudes were found for invalidly cued targets. It might be that interactions between perceptual closure processing of the ventral pathway and spatial target processing of the dorsal pathway contributed to the present result. We conclude that KFs automatically capture spatial attention when used as visual cues.

Image-guided navigation: the surgeon's perspective on performance consequences and human factors issues

Image‐guided navigation (IGN) represents a first step in the automation of surgical functions. The use of IGN can involve several human factors issues that must be taken into account when evaluating their impact on surgical performance and patient safety.

The effects of level of automation on the out-of-the-loop unfamiliarity in a complex dynamic fault-management task during simulated spaceflight operations

Out-of-the-loop unfamiliarity (OOTLUF) and information sampling strategies were examined after operator use of intelligent fault management (FM) support in interaction with a generic, autonomous, atmospheric control system. A simulated model-based reasoning agent provided fault diagnosis and recovery at three different levels of automation (LOA). In about 10% of the experimental trials FM support was withdrawn simulating a catastrophic failure. This allowed investigating OOTLUF potentially developed during reliable FM automation and its variation as a function of LOA. Dependent measures were the percentage of time the system was out-of-target, time elapsed until a repair was initiated, alarm reaction time, accuracy of manual tank level recordings, information sampling behavior, and subjective ratings of workload, tension, fatigue, self-confidence and trust in automation. It was found that automated FM support improved overall system performance and reduced subjective operator workload. OOTLUF occurred in terms of longer times until repair initiation only at medium LOA and not as expected at high LOA. A differential effect of LOA on information sampling strategies was observed suggesting that offloading operators from recovery implementation at high LOA during reliable automation enabled engagement in fault assessment activities, thereby maintaining situation awareness. It is concluded that for avoiding OOTLUF in complex, dynamic tasks, involving intelligent FM support, the important factor is not simply the LOA, but the ability of a particular LOA to support the human operators information sampling and higher-level reasoning activities.

Mismatch negativity on the cone of confusion

Localization of sounds by the auditory system is based on the analysis of three sources of information: interaural level differences (ILD, caused by an attenuation of the sound as it travels to the more distant ear), interaural time differences (ITD, caused by the additional amount of time it takes for the sound to arrive at the more distant ear), and spectral cues (caused by direction-specific spectral filter properties of the pinnae). Although in a number of psychophysiological studies cortical processes of ITD and ILD analysis were investigated, there is hitherto no evidence on the cortical processing of spectral cues for sound localization. The objective of the present experiment was to test whether it is possible to observe electrophysiological correlates of sound localization based on spectral cues. In an auditory oddball experiment, 80 ms of broadband noise from varying free field locations were presented to inattentive participants. Mismatch negativities (MMNs) were observed for pairs of standards and location deviants located symmetrically with respect to the interaural axis. As interaural time and level differences are identical for such pairs of sounds, the observed MMNs most likely reflect cognitive processes of sound localization utilizing the spectral filter properties of the pinnae. MMN latencies suggest that sound localization based on spectral cues is slower than ITD- or ILD-based localization.

Ship Management Attitudes and Their Relation to Behavior and Performance

Objective: The aim of this study was to adapt the Crew Resource Management (CRM) Attitudes Questionnaire (CMAQ) to the maritime domain, to assess the ship management attitudes of junior naval officers, and to determine the extent to which these attitudes correlate with behavior and performance in a naval exercise. Background: CRM attitudes have been shown to be associated with performance in aviation, but it is unclear whether this construct is applicable and relevant to the maritime domain. Method: Participants were 121 active seafarers and 101 junior officers of the German Navy who completed the Ship Management Attitudes Questionnaire–German Navy (SMAQ-GN). Ratings of nontechnical skills and ratings of mission success of the junior officers were collected during a real-world naval exercise. Results: Internal consistencies of SMAQ-GN were similar to those of the original CMAQ and retest reliability was rather high. Attitudes of junior officers toward communication and coordination were positive. Regarding command responsibility and the recognition of stressor effects, positive as well as neutral and negative attitudes were found. Overall, attitudes did not correlate with behavior and performance. Separate analysis of those participants reporting negative to neutral ship management attitudes showed substantial positive correlations of attitudes with behavior and performance. Conclusion: Ship management attitudes play a significant role in commanding ships. The attitude–performance linkage is not linear. Behavior and perfor-mance are less effective in officers with negative attitudes and equally effective in officers with slightly positive and very positive attitudes. Application: Ship management attitudes can be used to assess training needs for nautical teams.

Social cognitive aspects of the participation in workplace health promotion as revealed by the theory of planned behavior

Health-promoting efforts strongly depend on individual cognitions such as attitudes as well as social cognitive aspects of the work environment such as leadership and support. Using the theory of planned behavior (TPB) as a theoretical frame, participation behavior of employees in courses offered by the workplace health promotion (WHP) program of the German Armed Forces was investigated. Social cognitive aspects of the work environment, such as leadership behaviors by setting an example or optimizing organization of work, were included in the TPB components of subjective norm and perceived behavioral control, which allowed for an investigation of the specific effects of leadership on WHP participation. A survey study with N=1385 members of the German Armed Forces was conducted in 2015 in Germany. Results showed that perceived behavioral control and attitudes towards WHP were the strongest predictors for WHP participation. While subjective norm was positively related to attitudes, it had a slightly negative effect on intention to participate in WHP activities. These findings suggest that the most effective way for leadership to increase WHP participation is to enhance perceived behavioral control. Quite contrary, creating a positive subjective norm regarding WHP participation may even result in psychological reactance.