Objectives: To report on the initial feasibility of using thermal infrared imaging as a complimentary tool for the physician to identify pathological thermal dysfunction in non-verbal PDD/MR subjects.
Methods: 110 PDD/MR subjects (22 F, 88 M), ages 4-58 (mean 18.9), were acclimatized for 15 minutes at a room temperature of 24°C, unrestrained, clothing removed over the body regions to be imaged. The subjects’ medication was not discontinued prior to the imaging session. Anxiety was minimized by the presence of parents or support workers and through the use of pictograms, toys, videos and small rewards. Infrared thermal videos of specific body regions were acquired with a FLIR SC640 camera mounted on a wheeled, adjustable tripod. Patients were invited to take specific posture by parents/support workers either verbally, using pictograms or gentle stimulation. The videos were displayed live to the subject.
Results: Strategies to put the patient at ease were successful in all but 10 imaging sessions i.e. at least one body region could be imaged satisfactorily. In failed cases, subsequent imaging sessions were usually successful, the subject being less apprehensive about the technique. Standard views of body regions were extracted from the acquired thermal videos. 74.2% of frames were good enough for further quantitative processing. Proper positioning of upper extremities was more difficult and the resulting thermal information was not always exploitable. A minimum of two imaging sessions is recommended. It ensures a stable thermal analysis and reduces the effects of environmental artefacts and uncontrollable factors. Abnormal thermal patterns were identified, although the clinical interpretation is complex due to physiological artefacts (e.g. self-mutilation) and medication. However, our preliminary work shows that important relevant information could be gained, which allowed the clinical staff to elaborate new hypotheses for physical, psycho-physical or behavioural observations.
Conclusions: Thermal infrared imaging is technically feasible (without constraint or medication) and can be a practical tool to assess thermal dysfunction in PDD/MR patients. The portability and non-invasive nature of the infrared camera certainly contribute to its success in imaging this typically difficult population. Future work will focus on the clinical interpretation of thermal sequences of PDD patients to establish the screening potential of IR thermal imaging for identifying pathology-related thermal dysfunction. We will also look at the impact of the treatment of potentially uncovered physical pathologies on the behaviours exhibited by the patients.