One of the problems with the Nexus or Alfine 8-speed internal gear hubs is that they only work with specific shifters. Until recently, a twist shifter was the only choice, but the Alfine group now has a Rapid-Fire trigger shifter. In either case, the shifters are made to fit on MTB or cruiser style handlebars (22.2 mm diameter). The larger diameter drop bars or mustache bars required the use of a $60 hubbub adapter, which works, but is a somewhat expensive kludge.
Our fine mechanic Mark (you may know him as "Mongo") figured out how to shift these hubs with a Shimano indexed bar-end shifter.
It works well.