Early sleep after action observation and motor imagery improved manual dexterity in patients after surgery for metacarpal and phalangeal fractures

Immobilization after surgical fixation for metacarpal and phalangeal fractures induces a decay in manual dexterity. Action Observation and Motor Imagery (AOMI) mitigate motor performance decline during hand immobilization, and early sleep after such approaches has been reported to further enhance the consolidation of motor learning in healthy subjects. Here, we investigated the effects of early sleep after AOMI training sessions in subjects with immobilization after surgical fixation for metacarpal and phalangeal fractures. Fifty-four subjects with immobilization of fourth and fifth fingers after fixation of metacarpal and phalangeal fractures were randomized into 3 groups undergoing a 2-week training. AOMI-sleep and AOMI-control groups performed AOMI of transitive manual dexterity tasks between 8:00 and 10:00 p.m. or between 8:00 and 10:00 a.m. respectively, while Control group observed landscape video-clips before sleeping. AOMI-sleep group demonstrated greater manual dexterity improvements than AOMI-control and Control groups at immobilization and training end (T1) and 1-month follow-up (T2). AOMI-sleep group revealed higher active range of motion of fourth and fifth fingers at T1 and T2, and greater hand grip strength at T2 than Control group. These findings suggested that AOMI followed by early sleep during the postoperative immobilization period may improve outcomes of subjects with metacarpal and phalangeal fractures.