Northstar Neuroscience shares sink 85%; Jefferies downgrades to underperform

NEW YORK, Jan 23, 2008 (Thomson Financial via COMTEX) -- NSTR | news | PowerRating | PR Charts -- Shares of Northstar Neuroscience Inc. sank to an all-time low Tuesday after the company said its Everest trial evaluating cortical stimulation to improve hand and arm function in stroke survivors failed to meet its primary efficacy endpoint.Next....