Importantly, the likely benefits of even limited visual restoration to a blind individual are often under appreciated by sighted individuals (Lane et al., 2012). Even rudimentary prosthetic vision in the setting of profound blindness may have significant positive psychological and functional ramifications for a blind individual, contributing to reduced feelings of isolation and depression (Dagnelie, 2008). Only a

few reproducible phosphenes may be ERK inhibitor clinical trial required to improve an individual׳s quality of life. For example, a recipient of the Dobelle implant was able to navigate independently and read letters on a Snellen chart with only 21 phosphenes at his disposal (Dobelle, 2000). In the most simple

of demonstrations, the reported elation felt by blind volunteers stimulated with only 4 occipital electrodes, in addition to their ability to independently locate a light source (Button and Putnam, 1962), suggests that questions of what constitutes “acceptable” performance by both recipients and treating physicians alike, needs to be carefully balanced. Progression to functional testing of a cortical implant is predicated on an uneventful implantation procedure and postoperative recovery. As discussed in Section 6.1.3, optimal surgical outcomes will depend partly on careful selection of implant recipients, for whom good general health will likely be a pre-requisite. Beyond this, there is a paucity of data on which to base firm statements about the risk of postoperative complications find more in current-generation cortical visual prosthesis recipients per se, however inferences can be made by drawing from older studies, the general (-)-p-Bromotetramisole Oxalate neurosurgical literature and recent reports on neuroprostheses implanted for other CNS disorders. The works of Brindley and Dobelle provide historical insights into the risks of cortical implant surgery,

although miniaturization of implant hardware, and improvements in operative technique and infection prophylaxis probably render these of little contemporary relevance. Nonetheless, recipients of implants from both groups reportedly suffered implant-related infections (Naumann, 2012 and Rushton et al., 1989). More recent large-series reports describe infection rates of 3.1% following the implantation of deep brain stimulators (DBS) (Fenoy and Simpson, 2014), 3.5% for hydrocephalus shunts (Parker et al., 2014) and 2.3% for subdural recording electrodes (Arya et al., 2013). While these figures are more informative, several factors suggest that these studies may overestimate the likely risk for future visual cortex implant recipients. Firstly, shunt candidates often present with comorbidities that increase their infection risk, while subdural recording electrodes incorporate externalized wires that provide a pathway for the intracranial migration of bacteria.