This is the DSM IV definition of Asperger's Syndrome, which has recently been folded into the Autism Spectrum Disorder. The old definition is a good analogue to a clinical description (if there was one) for a Xenos person.
DSM IV is significant because this was the last diagnostic tool to list “Asperger's Syndrome†before it was lumped in with “Autism Spectrum Disorderâ€. The distinctions and lives outside of disability were largely lost. A good starting explanation of Xenos is Asperger's that doesn't get to the level of debilitation.
Highlighted text is a reinterpretation of DSM IV that seems to fit Xenos more accurately.
A. [asocial - WeDoNotDoConferences, please] Qualitative impairment in social interaction, as manifested by at least two of the following:
B. [obsession - deep explorers and observers] Restricted repetitive and stereotyped patterns of behavior, interests, and activities, as manifested by at least one of the following:
C. The disturbance causes clinically significant impairment in social, occupational, or other important areas of functioning [ This is the difference between Xenos (no significant impairment in these) and Autism (Xenos with clinically significant impairment for these and the rest) ]
D. There is no clinically significant general delay in language (e.g., single words used by age 2 years, communicative phrases used by age 3 years).
E. There is no clinically significant delay in cognitive development or in the development of age-appropriate self-help skills, adaptive behavior (other than social interaction), and curiosity about the environment in childhood.