“…Numerous eponymous clinical variants of sporadic CJD have long been recognized (6, 59, 74), although recent prospective CJD surveillance studies have found that the boundaries between these clinical subgroups are frequently ill-defined (77,82). Most cases of CJD occur in adults aged 60-65, although it has been recognized for many years that a wide age range can be affected, from teenagers to patients in their ninth decade (10,16,19,53,64,67,82). The UK CJD Surveillance Project has found in recent years an apparently increasing number of CJD cases in individuals aged 75 and over, which appears to be a consequence of increased diagnostic vigilance in the elderly (76,82).…”