RESUMEN
Transcranial direct current stimulation (tDCS) applied to the primary motor cortex (M1) improves motor learning in relatively simple motor tasks performed with the hand and arm. However, it is unknown if tDCS can improve motor learning in complex motor tasks involving whole-body coordination with significant endpoint accuracy requirements. The primary purpose was to determine the influence of tDCS on motor learning over multiple days in a complex over-hand throwing task. This study utilized a double-blind, randomized, SHAM-controlled, between-subjects experimental design. Forty-six young adults were allocated to either a tDCS group or a SHAM group and completed three experimental sessions on three consecutive days at the same time of day. Each experimental session was identical and consisted of overhand throwing trials to a target in a pre-test block, five practice blocks performed simultaneously with 20 min of tDCS, and a post-test block. Overhand throwing performance was quantified as the endpoint error. Transcranial magnetic stimulation was used to obtain motor-evoked potentials (MEPs) from the first dorsal interosseus muscle to quantify changes in M1 excitability due to tDCS. Endpoint error significantly decreased over the three days of practice in the tDCS group but not in the SHAM group. MEP amplitude significantly increased in the tDCS group, but the MEP increases were not associated with increases in motor learning. These findings indicate that tDCS applied over multiple days can improve motor learning in a complex motor tasks in healthy young adults.
RESUMEN
Cutaneous sclerosis occurs in association with a variety of systemic diseases, including hematologic malignancy, plasma cell dyscrasias, solid organ tumors, and other systemic autoimmune conditions. Herein, we present a unique case of morphea/lichen sclerosus overlap arising in association with aplastic anemia. To expand upon this rare case, we also review the literature surrounding paraneoplastic sclerosing skin disorders. A 53-year-old man presented with a 13-month history of progressive and generalized skin changes. Exam revealed irregular, hypopigmented indurated plaques with focal areas of scale on the bilateral axillae and hips, as well as hyperpigmented brown papules and plaques on the back. Laboratory evaluation revealed pancytopenia and positive anti-nuclear antibody (1:160). Bone marrow biopsy demonstrated hypocellular marrow consistent with aplastic anemia. Furthermore, skin biopsies revealed lichen sclerosus overlying superficial morphea, consistent with a paraneoplastic sclerodermoid-like eruption. While preparations for hematologic-directed therapies were made, skin-directed therapy with a combination topical steroids and topical calcineurin inhibitors was initiated. Eosinophilic fasciitis and scleroderma have been linked to aplastic anemia, and herein, we expand upon this phenomenon by presenting our case of generalized plaque morphea/lichen sclerosus overlap arising in the setting of aplastic anemia. Dermatologists must be aware of this rare association in order to identify precocious hematologic disease.