Two case reports of two women, in their early thirties, with type I malformation were described.3, 4 Symptoms of anxiety preceded the diagnosis of the malformation in both cases. Grosso et al. reported an association of mental retardation, speech delay, and epilepsy with Arnold–Chiari type I malformation.5 In veterinary medicine literature, Shamir et al described symptoms of progressive ataxia, tremors, and dementia in a female African lion. The symptoms appeared at age of 3 months and the lion died 6 months later. Postmortem examination revealed Arnold–Chiari type II malformation.6
In our patient, diagnosis of Arnold–Chiari type I malformation is made through a combination of patient history, neurological examination, and Magnetic Resonance Imaging. Her memory impairment and functional decline are consistent with diagnosis of dementia. Symptoms of dementia succeeded the diagnosis of the malformation. Development of early dementia in association with Arnold–Chiari malformation in this patient has been a clinical dilemma. It is likely that Arnold–Chiari malformation and dementia have two separate course of illness. However, the possibility that the malformation might have triggered the neuropathological process of dementia cannot be ruled out. It is reasonable to hypothesize that the neuroanatomical anomaly itself might have caused memory impairment, particularly in a predisposed patient, or traction on the brain might have directly induced memory decline.