PROGRESSIVE ISOLATED AMNESIA is a diagnosis for patients who exhibit slowly progressive memory deficits without any other cognitive impairment.1,2 Such patients are difficult to diagnose and their long-term course remains unclear. Herein, we report eight years of follow up with neuropsychological and neuroimaging data of a patient who developed isolated slowly progressive amnesia.

The patient was a 72-year-old right-handed housewife. At the age of 61, she was shocked when she heard that her husband had been unfaithful to her. Her family reported that she began to show signs suggesting loss of recent memory from that time. When she was 63, she was prescribed anti-anxiety agents for emotional instability (e.g. severely blaming her husband). At the age of 64, she was referred to our outpatient clinic for memory complaints. She had taken social dance lessons and played golf, but complained of difficulties remembering the dance steps and golf scores. She scored 29/30 on the mini-mental state examination (MMSE). She was unable to recall one of three words included in the MMSE. Her Wechsler Adult Intelligence Scale Revised Full-Scale Intelligence Quotient (WAIS-R FSIQ) score was 115. She achieved five categories on the modified Wisconsin Card Sorting Test, indicating no deficit of executive function. Her Wechsler Memory Scale Revised (WMS-R) delayed recall score was severely impaired (<50). Magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT) scans revealed no significant abnormality. After the check-up, she discontinued receiving regular follow up. Eight years later, at the age of 72, she was referred to our outpatient clinic again for severe memory complaints. She repeated the same questions at short intervals and was unable to respond to questions regarding the current date and her age. She could not remember what she had eaten or whom she had met just several hours prior. She compensated for her memory loss by taking notes. Even at this time, her general intellectual function was intact, as she scored 118 on the WAIS-R FSIQ. In contrast, her memory test scores indicated severe anterograde amnesia. The MMSE score showed a decrement of five points compared with that at the age of 64, with failures pertaining to time orientation and recall of three words. Her WMS-R delayed recall score was 50. A structured interview about autobiographical memory3 revealed that she remembered episodes occurring before the onset of the disease well. MRI and SPECT scans showed atrophy and decreased perfusion of the bilateral hippocampus.

This patient was diagnosed with progressive isolated amnesia based on the severe anterograde amnesia without deterioration of general intellectual function and localized atrophy of the hippocampus. As suggested by the course of this patient, such patients tend to be misdiagnosed with normal age-related cognitive losses or other psychiatric disorders. Early recognition of this amnesic disease is necessary in order to support these patients.


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