How Does Functional Neurodiagnostics Inform Surrogate Decision-Making for Patients with Disorders of Consciousness? A Qualitative Interview Study with Patients’ Next of Kin

Abstract

Background

Functional neurodiagnostics could allow researchers and clinicians to distinguish more accurately between the unresponsive wakefulness syndrome (UWS) and the minimally conscious state (MCS). It remains unclear how it informs surrogate decision-making.

Objective

To explore how the next of kin of patients with disorders of consciousness (DOC) interpret the results of a functional neurodiagnostics measure and how/why their interpretations influence their attitudes towards medical decisions.

Methods and Sample

We conducted problem-centered interviews with seven next of kin of patients with DOC who had undergone a functional HD-EEG examination at a neurological rehabilitation center in Germany. The examination included an auditory oddball paradigm and a motor imagery task to detect hidden awareness. We analyzed the interview transcripts using structuring qualitative content analysis.

Results

Regardless of the diagnostic results, all participants were optimistic of the patients’ meaningful recovery. We hypothesize, that participants deal with the results of examinations according to their belief system. Thus, an unfavorable evaluation of the patient’s state (e.g., a “negative” HD-EEG-result) had the potential to destabilize the participant’s belief system. To re-stabilize or to prevent the destabilization of their belief system, participants used different strategies. Participants accepted a “positive” HD-EEG result since it stabilized their belief system.

Conclusion

We hypothesize, that a group of next of kin of patients with DOC deals with functional neurodiagnostics results on the basis of the result’s value and their high hope that the patient will recover meaningfully. A psychological mechanism seems to moderate the impact of functional neurodiagnostics on surrogate treatment decisions.

Appendix 1

Functional HD-EEG-Examination to Detect Residual Conscious Awareness

The functional HD-EEG examination consisted of a protocol with two sections. The researchers performed both examinations with each patient. The first part was an auditory oddball paradigm using 4 blocks of standard and target stimuli with 10 target and 40 standard stimuli per block, which were presented randomized within each block. Stimuli consisted of 1500 Hz and 1000 Hz tones, respectively, with 500 ms duration and a 500 ms inter-stimulus interval. The main experiment was preceded by the presentation of 2 target and 8 standard tones as demonstration. Patients were instructed to listen to the target tones attentively. The experimental procedure was identical to the one described in a prior publication by one of the authors of this study and colleagues [83].

The second part involved a command-following paradigm. Using a randomized block-structure, a resting condition and a mental motor imagery condition were tested in 6 blocks per condition with 15 trials per block. Each block was preceded by a verbal instruction and each trial was announced by an auditory trigger signal. The method was based on the experiment by Cruse et al. (2011) [21]. It tested command-following using an ERP-based mental motor imagery, instructing participants to either squeeze their right hand or to wiggle the toes. Yet, the paradigm, which was used in the rehabilitation clinic, entailed different movements than in the experiment of Cruse et al. (2011), in order to achieve a higher activation of the motor cortex following the instruction: For the motor imagery task, the patient received the instruction to imagine raising his/her arms and lowering them again when an auditive trigger-sound appeared. This condition was statistically compared to the findings obtained during a resting period, which was also indicated by auditive trigger-sounds. For the resting periods, patients were instructed to listen to the auditive trigger-sounds. The examination was repeated on a second day to reduce the influence of possibly confounding factors like tiredness. All exams were conducted by research personnel (a psychologist and a study nurse) specifically trained in conducting HD-EEG exams and data analyses. The mental motor imagery condition was statistically compared to the resting condition. The examination was repeated on a second day to reduce the influence of possibly confounding factors like alertness or tiredness. All exams were conducted by research personnel specifically trained in neurodiagnostics measures.

Standardized Written Report of the Findings of the HD-EEG Examination

In addition to the scientific purpose of the study, the results of the HD-EEG exams were always communicated in a standardized way using a written report. The reports were prepared by the researchers and revised by physicians experienced in the field of neuro-rehabilitation and trained in the interpretation of the functional HD-EEG paradigm by one of the head physicians. The HD-EEG report included a detailed description of the examinations, the individual patient’s results and a discussion of these results in comparison with a population of healthy individuals. In respect to the auditory oddball paradigm (p300), the report included the extracted waveforms and topographies of the stimulus groups (standards and targets). Based on the waveform (amplitude and latency) as well as the topographical distribution of the p300 component, the quality of the brain response to the presented stimuli was rated. In respect to the mental motor imagery paradigm, the accuracy of the machine learning classifier was reported, expressing the performance of the patient to follow the instructions. Additionally, the statistical difference between the resting and the mental motor imagery condition was reported. The report then stated if and how well the patient was able to follow the instructions and compared the performance to a control group of healthy controls. The report concluded with an overall evaluation of the patient’s level of consciousness. Here it compared the results of the HD EEG with the results of the structured clinical examinations with the Coma Recovery Scale Revised (CRS-R) [84]. In case that the results of both measures were at odds with each other, this was stated and explained with regard to a variability of a patient’s arousal during the exams. Reports described the HD-EEG as an experimental scientific measure and stated that results would never be used alone to guide medical decisions. Doctors attached the HD-EEG-reports to the patient’s medical chart and sent them out to the patient’s general physician as well as to his/her legal representative within one to two weeks after the patient’s discharge. The process of oral disclosure of the results was not standardized. Usually, the results of the examinations were mentioned in the medical discharge conversations between doctors and patients’ next of kin, embedded in a more general evaluation of the patient’s condition and prognosis.