PHILADELPHIA – Loud snoring and insomnia used to be merely annoying. Now they are big business. In Philadelphia and across the country, sleep-diagnostic centers are popping up and people once aggravated by a lousy night’s sleep are getting help. One beneficiary of the push for more testing is a local company, Viasys Healthcare Inc., which makes medical equipment including devices to diagnose and treat sleep ailments like sleep apnea, a condition in which breathing stops repeatedly for brief periods during sleep. In the five years since Viasys was spun off from a Boston-area company, Thermo Electron Corp., sales of its […]