Former Major General Pyotr Grigorenko spent 34 of his 63 years in the Soviet Army. In 1961, however, he had the temerity to criticize the "Khrushchev cult" at a party meeting. That outburst eventually cost him his army career, and sent him off to an asylum for 14 months as a "schizophrenic." In time, the old soldier became one of the most vigorous and spirited dissenters against the current regime. Seven months ago when he arrived in Tashkent to act as counsel for ten Crimean Tartars who were on trial for civil rights activities, Grigorenko was arrested for "anti-Soviet agitation." Last week, a medical board in Tashkent decreed that he was "paranoid with symptoms of atherosclerosis" and dispatched him to another asyluma favorite Soviet prescription for discrediting dissenters. Also reported to be held in a Soviet state institution last week: Ivan Yakhimovich, onetime chairman of a Latvian collective farm, who betrayed his mental aberration in 1968 by supporting Alexander Dubček's liberal Communist regime in Czechoslovakia.