These three main outcomes have led to the generation of the following groups of scientific knowledge:
1) In the network analysis, we identified 8 different clusters corresponding to (1) Depression, (2) Fatigue-related activity limitations, (3) Fatigue-related physical impairment, (4) Fatigue-related participation restrictions, (5) Well-being vitality, (6) Impact on everyday functioning, (7) Cognition & Motor, and (8) Respiratory disability. We identified three bridge symptoms: 'feeling incapable of carrying out projects' (VQ11-6) bridges the 'Fatigue-related participation restrictions' and 'Impact on everyday functioning' syndromes; 'Feeling bad about yourself' (PH9-6) bridges the 'Depressive syndrome' and 'Cognition & Motor' syndromes; and fatigue frequency (PH9-4) bridges the fatigue-related syndromes and depressive syndromes.
Interestingly, the symptom network confirms the distinction we made between fatigue severity (measured in terms of intensity or frequency) and fatigue-related disability (in terms of impairment, activity limitations, and participation restrictions): these different characterizations of fatigue play distinct roles in the symptom network, and particular attention to their differentiation should therefore be emphasized in studies investigating fatigue in cancer. Furthermore, we did not find any link between fatigue-related disability and depression: the connection between fatigue and depression occurs through aspects of fatigue severity (intensity and frequency). Finally, we did not find any significant structural differences between the networks based on the treatments received or the duration of survivorship.
2) In identifying vocal biomarkers of fatigue, we aimed to determine the specific sensitivity of these markers to different symptoms, independent of 8 confounding factors (age, Body Mass Index, education level, history of chemotherapy, surgery, radiotherapy, hormone therapy, and whether the participant was still undergoing treatment at the time of recording). We decoupled our features from these factors and observed that reading errors are significantly affected by having received radiotherapy; articulatory flow characteristics are primarily influenced by age; and phonatory articulation characteristics are mainly affected by BMI, age, and hormone therapy.
We then examined the sensitivity of these descriptors to symptoms after accounting for the influence of confounding factors. Among the vocal biomarkers identified for fatigue, we found that reading errors were preferentially related to physical impairment due to fatigue (dim 3) and respiratory quality of life (dim 8); articulatory flow was linked to these same dimensions, as well as to cognitive and motor aspects (dim 7); finally, phonatory articulation quality metrics appeared sensitive to all the measured dimensions, though they were not highly specific to any of them.