Limb-kinetic apraxia in a patient with mild traumatic brain injury

RATIONALE We report on a patient who developed limb-kinetic apraxia (LKA) due to an injured corticofugal tract (CFT) from the secondary motor area following mild traumatic brain injury (TBI), demonstrated on diffusion tensor tractography (DTT). PATIENT CONCERNS She was struck in the right leg by a sedan at a crosswalk and fell to the ground. She lost consciousness and experienced post-traumatic amnesia for approximately ten minutes. She was obliged to wear a cast for a left humerus fracture for two months, and she found she could not move her left hand quickly with intention after removal of the cast; consequently her left hand was almost non-functional. When she visited the rehabilitation department of a university hospital two years after the crash, she had mild weakness of the left upper extremity (manual muscle test: 4/5). However, the movements of the left hand were slow, clumsy, and mutilated when executing grasp-release movements of her left hand. DIAGNOSES A 44-year-old female suffered head trauma resulting from a pedestrian car accident. INTERVENTIONS When she extended all her left fingers, it took approximately eight seconds at her fastest speed to perform the pattern extending from the thumb to little finger sequentially. OUTCOMES On two-year DTT, narrowing and partial tearing was observed in the right supplementary motor area (SMA)-CFT. LESSONS Injury of the right SMA-CFT was demonstrated in a patient with LKA in a hand following mild TBI. Our results stress the need to evaluate the CFTs from the secondary motor area for patients with unexplained motor execution problems following mild TBI.