Table 1.
Examples, inter-rater reliability, and frequency of use for each category and subcategory in the EEG-NF arm.
| Category | Example | Cohen’s kappa coefficient | n | % useda |
|---|---|---|---|---|
| Behavior | 1.00 | 94 | 40.52% | |
| Relaxation | I tried to relax | 62 | 26.72% | |
| Breathing | Paid attention to breathing steadily | 45 | 19.40% | |
| Physical activity | Pressed tongue against upper jaw | 5 | 2.16% | |
| Concentration | 0.69 | 30 | 12.93% | |
| Concentration on task | Directing all [mental] energy toward the task | 11 | 4.74% | |
| Concentration on self/body | Feeling [the] feet firmly on the ground | 7 | 3.02% | |
| Concentration on surroundings | Focus on the text on the monitor | 14 | 6.03% | |
| Distraction | 62 | 54 | 12.93% | |
| Distraction everyday life | To-do lists in my head | 21 | 9.05% | |
| Distraction music/movies | Train ride with specific people that always get in Played/sang a song in my head, played a movie trailer in my head |
32 | 13.79% | |
| Distraction words/numbers | Counted forwards and backwards | 8 | 3.45% | |
| Emotion | 1.00 | 75 | 1.72% | |
| Inducing positive emotions | Thoughts of nice situations with grandchild | 71 | 30.60% | |
| Inducing negative emotions | Negative thoughts, rejection | 4 | 1.72% | |
| Imagination | 0.72 | 77 | 33.19% | |
| Imagination of changed visual perception | Looking for people in the meals | 2 | 0.86% | |
| Imagination of movement | Sense of exercising/jogging | 2 | 0.86% | |
| Imagination of food defense | Pushing the pictures away in my thoughts | 0 | 0.00% | |
| Imagination of food neutral | Imagined how the food is made | 16 | 6.90% | |
| Imagination of food positive | No prohibitions, enjoying small portions | 15 | 6.47% | |
| Imagination of food negative | Concerning the sweets, I imagined all that sugar [in the depicted food] and pretended it was poison | 17 | 7.33% | |
| Imagination for positive self-motivation | Imagined the new, healthy life I would have after weight reduction | 32 | 13.79% | |
| Imagination for negative self-motivation | I saw myself as a very fat man | 3 | 1.29% | |
| Self-Talk | 0.27 | 17 | 7.33% | |
| Verbal avoidance of overeating | When [shown] unhealthy food, I thought “Go away!” | 7 | 3.02% | |
| Verbal directed at self | Sentences like “I am in control!,” “I decide, not the food” | 11 | 4.74% | |
| Thought | 0.86 | 48 | 20.69% | |
| Thoughts of nothing specific | Tried to empty head | 42 | 18.10% | |
| Thoughts of food avoidance | Seeing the food without thinking about it | 7 | 3.02% | |
| No strategyb | Tried several things Hard to explain |
1 | 0.43% |
EEG, electroencephalography; NF, neurofeedback; rtfNIRS, real-time functional near-infrared spectroscopy; N = 232. Percentage of subcategories refer to the number of reports of subcategory use relative to the total of N = 232 reports. Number of reports of subcategory may not sum up to the number of overarching categories because overarching categories were only assigned in a dichotomous format (yes/no).
Because the category scheme was derived across arms (rtfNIRS-NF, EEG-NF, and delayed rtfNIRS-NF), frequency of strategy use is more equally distributed upon joint consideration of arms as opposed to the separate consideration of strategy use in the EEG-NF arm only in this table.
The low number of participants using “No Strategy” potentially undermined the validity of inter-rater reliability analyzes.