I think that the etiology of his symptoms is multifactorial.  He probably does have a mild peripheral neuropathy, but the sparing of ankle jerks suggested either the neuropathy is mild or that there is a superimposed myelopathic process such as a cervical or lumbosacral myelopathy.  He really is most concerned about the fatigue and I think it is possible due to suboptimally treated depression and suboptimally treated sleep apnea.  Whether he has another underlying muscular disorder such as a primary myopathy remains to be seen.