Effects of contact with a dog on prefrontal brain activation in patients in a minimally conscious state: A controlled crossover trial

Abstract

The first studies have indicated that animal-assisted therapy benefits patients in a minimally conscious state (MCS), but the evidence is scarce. It is thus crucial to understand how these patients react to animal contact. This study aimed to measure the prefrontal brain activation in MCS patients during contact with a dog compared with a plush animal using functional near-infrared spectroscopy (fNIRS). We conducted a controlled crossover trial with 22 MCS patients, who each participated in six sessions. Patients interacted with a dog in three sessions and with a plush animal in three control sessions. Each session consisted of five 2-minute phases with a neutral phase at the start and the end. The contact intensity with the dog or the plush animal increased from the second to the fourth phase. The fNIRS parameters did not differ between the conditions. The mean heart rate was significantly higher in the dog condition than in the control. In both conditions, prefrontal brain activation, mean heart rate, and one heart rate variability parameter increased with the increased intensity of contact with the dog and plush animal. The results show that MCS patients react with the same prefrontal brain activation during contact with a dog and a plush animal but have increased heart rate in contact with the dog, indicating physiological arousal. These findings suggest that the incorporation of animals into MCS therapy has the potential to stimulate patients, thereby facilitating greater participation. However, more research is needed to understand the effects of animals on brain activation.

Keywords: Brain activation; Functional near-infrared spectroscopy; Heart rate; Human–animal interaction; Minimally conscious state; Neurorehabilitation.