Selective Brain Hypothermia in the Comprehensive Rehabilitation of Patients with Chronic Consciousness Disorders

Abstract

Aim: to evaluate clinical effectiveness of selective hypothermia of cerebral cortex for the recovery of awareness in patients with chronic disorders of consciousness (CDC). Material and methods. 111 patients with CDC 30 and more days after a cerebral event (ischemic or hemorrhagic stroke, brain injury) were included in the study. Exclusion criteria were anoxic brain injury (sequelae of a prolonged asystole or asphyxia), active sepsis, arrhythmia, baseline hypothermia (body temperature lower than 35.5 °С). Experimental group included 60 patients, of them 39 patients were in a vegetative state (VS), 21 patients exhibited patterns of minimally conscious state (MCS). Control group incluted 51 patients, of them 32 patients were in VS and 19 patients were in MCS. Patients in the experimental group received 10 sessions (120 minutes each) of selective brain hypothermia (SBH) during the 14-days follow-up period. Patients of both groups received standard identical neurological treatment and rehabilitation procedures. Patients in the control group did not undergo brain hypothermia. The induction of SBH involved cooling of the whole surface of the craniocerebral area of scalp using special helmets. The temperature of the internal surface of the helmet was 3–7 °С. Temperature of the frontal lobes of the cortex was monitored with non-invasive microwave radiothermometry, axillary temperature was also registered. The level of consciousness was evaluated using «Coma Recovery Scale-Revised» (CRS-R) scale. Results. 120-minutes long SBH session reduced the temperature of the frontal lobes of the cerebral cortex by 2.4–3.1 °С with no impact on the axillary temperature. Evaluation using CRS-R revealed improvement in all studied functions (auditory, visual, motor, oromotor, communication, arousal) in patients in the experimental group after 10 SBH sessions. Level of consciousness in patients from the experimental group in VS increased from 4.5 ± 0.33 to 8.7 ± 0.91 points (P < 0.001), for patients in MCS from 11.3 ± 1.0 to 18.2 ± 0.70 (P < 0.001) points. In the control group, scores of patients in VS rose from 4.3 ± 0.37 to 6.8 ± 0.49 (P < 0.001) points with the most significant changes in auditory and visual functions (P<0.001). In the control group of patients in MCS the oromotor function improved (P < 0.05), overall CRS-R scores changed insignificantly from 9.1 ± 0.57 to 10.1 ± 0.86 (P < 0.1). The best outcome (CRS-R > 19 points) was seen in patients from the experimental group [6 in VS (15.4 %) and 8 in MCS (31.8 %)]. In the control group, the best results did not exceed 10 points for the patents in VS, while 4 patients in MCS (21 %) reached 12–16 scores. During 30-day follow-up period of hospitalization after the SBH sessions mortality rate was 10 % (6 patients) in the experimental group and 21.6% (11 patients) in the control group. Conclusion. Patients with CDC could benefit from serial SBH sessions performed as a part of comprehensive treatment and rehabilitation strategy. We suggest that selective reduction of frontal lobe temperature improves neurogenesis, neuronal regeneration, and neuroplasticity.