Introduction X-linked myopathy with excessive autophagy (XMEA) is characterized by autophagic vacuoles with sarcolemmal features. Mutations in VMA21 result in insufficient lysosome acidification, causing progressive proximal weakness with onset before age 20 and loss of ambulation by middle age. Methods We describe a patient with onset of slowly progressive proximal weakness of the lower limbs after age 50 who maintains ambulation with the assistance of a cane at age 71. Results Muscle biopsy at age 66 showed complex muscle fiber splitting, internalized capillaries, and vacuolar changes characteristic of autophagic vacuolar myopathy. Vacuoles stained positive for sarcolemmal proteins, LAMP2, and complement C5b-9. Ultrastructural evaluation further revealed basal lamina reduplication and extensive autophagosome extrusion. Sanger sequencing identified a known pathologic splice site mutation in VMA21 (c.164–7T>G). Conclusions This case expands the clinical phenotype of XMEA and suggests VMA21 sequencing be considered in evaluating men with LAMP2-positive autophagic vacuolar myopathy.

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To fulfill the need for reliable and consistent medical training of the neurological examination technique to assess ankle clonus, a series elastic actuator (SEA) based haptic training simulator was proposed and developed. The simulator's mechanism (a hybrid of belt and linkage drive) and controller (impedance control) were designed to render a realistic and safe training environment. Benchtop tests demonstrated that the prototype simulator was able to accurately estimate the interaction torque from the trainee (average RMSE of 0.2 Nm) and closely track a chirp torque command up to 10 Hz (average RMSE of < 0.22 Nm). The high-level impedance controller could switch between different clinically encountered states (i.e., no clonus, unsustained clonus, and sustained clonus) based on trainee's assessment technique. The simulator was evaluated by a group of 17 experienced physicians and physical therapists. Subjects were instructed to induce sustained clonus using their normal technique. The simulator was assessed in two common clinical positions (seated and supine). Subjects scored simulation realism on a variety of control features. To expedite controller design iteration, feedback from Day 1 was used to modify simulation parameters prior to testing on Day 2 with a new subject group. On average, all subjects could successfully trigger a sustained clonus response within 4-5 attempts in the first position and 2-3 in the second. Feedback on the fidelity of simulation realism improved between Day 1 and Day 2. Results suggest that this SEA-based simulator could be a viable training tool for healthcare trainees learning to assess ankle clonus.

Patients with neuromuscular disorders such as Parkinson’s disease (PD), traumatic brain or spinal cord injury, or multiple sclerosis (MS) can develop different levels of abnormal muscle behavior (hypertonia) such as rigidity and spasticity [1], [2]. Hypertonia can affect different parts of the body such as upper or lower extremities. Symptoms include pain, increased muscle tone, spasms, and decreased functional abilities. Hypertonia can interfere with many activities of daily living, greatly affecting the quality of life in patients and causing anxiety, depression, and social isolation [2].

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