Lennox reported that 22% of 1905 epileptic patients had mild mental retardation, 12% had moderate mental retardation, and 2% had severe mental retardation. Thus, about 2/3 of epileptic patients have normal intelligence; 1/7 of patients have significantly low intelligence. “Grand mal”, frontal lobe lesions are most likely to cause personality and intelligence changes. Some patients with milder mental retardation may gradually recover when seizures are controlled. In severe cases, the decline is mostly progressive. This kind of dementia is also called epileptic dementia. It begins with a loss of near memory, followed by distant memory, comprehension, calculation, analysis and judgment. They also have the common characteristics of epileptic patients in terms of thinking, emotion and behavior – stagnation and stereotypy: they are overly meticulous, meticulous in their work, stubbornly stuck to the patterns they have become accustomed to, stuck to the rules, unchanging, and have difficulty adapting to new and changing environments.