Stick balancing on the fingertip is a complex voluntary motor task that requires the stabilization of an unstable system. For seated expert stick balancers, the time delay is 0.23 s, the shortest stick that can be balanced for 240 s is 0.32 m and there is a % 0:88 dead zone for the estimation of the vertical displacement angle in the saggital plane. These observations motivate a switching-type, pendulum -cart model for balance control which uses an internal model to compensate for the time delay by predicting the sensory consequences of the stick's movements. Numerical simulations using the semi-discretization method suggest that the feedback gains are tuned near the edge of stability. For these choices of the feedback gains, the cost function which takes into account the position of the fingertip and the corrective forces is minimized. Thus, expert stick balancers optimize control with a combination of quick manoeuvrability and minimum energy expenditures.

Synopsis A new era of surgical visualization and magnification is poised to disrupt the field of otology and neurotology. The once revolutionary benefits of the binocular microscope are now shared with rigid endoscopes and exoscopes. These two modalities are complementary. The endoscope improves visualization of the hidden recesses through the external auditory canal or canal up mastoidectomy. The exoscope provides an immersive visual experience and superior ergonomics compared to binocular microscopy. Endoscopes and exoscopes are poised to disrupt the standard of care for surgical visualization and magnification in otology and neurotology.

There has been a rapid increase in endoscopic ear surgery for the management of middle ear and lateral skull base disease in children and adults over the last decade. In this review paper, we discuss the current trends and applications of the endoscope in the field of otology and neurotology. Advantages of the endoscope include excellent ergonomics, compatibility with pediatric anatomy, and improved access to the middle ear through the external auditory canal. Transcanal endoscopic ear surgery has demonstrated comparable outcomes in the management of cholesteatoma, tympanic membrane perforations, and otosclerosis as compared to microscopic approaches, while utilizing less invasive surgical corridors and reducing the need for postauricular incisions. When a postauricular approach is required, the endoscopic-assisted transmastoid approach can avoid a canal wall down mastoidectomy in cases of cholesteatoma. The endoscope also has utility in treatment of superior canal dehiscence and various skull base lesions including glomus tumors, meningiomas, and vestibular schwannomas. Outside of the operating room, the endoscope can be used during examination of the outer and middle ear and for debridement of complex mastoid cavities. For these reasons, the endoscope is currently poised to transform the field of otology and neurotology.