It is difficult to exactly refer symptoms to either the office or the home environment.
In field investigations by Saijo et al.
(2004) on home environments, SBS-type symptoms occurring ‘‘sometimes’’ or ‘‘usually’’ in the last 3 months and improving away from home were commonly defined as SBS positive symptoms, and a person having at least one positive symptom was regarded as SHS positive.
However, in other investigations, symptoms occurring ‘‘sometimes’’ were not regarded as positive (Engvall et al., 2001).