Adult onset familial normal pressure hydrocephalus? Neuropsychological profile of monozygotic twins

Abstract

Background There are few cases of adult onset familial normal pressure hydrocephalus (NPH) reported in the literature but the rarity of the disease makes coincidence unlikely. Female monozygotic twins presenting with the NPH triad of symptoms were assessed on a neuropsychological test battery. The aims were to determine whether the neuropsychological evidence could support the differential diagnosis of adult onset NPH whilst contributing to a further understanding of the neuropsychological profile of adult NPH. Materials and methods Both twins were assessed on neuropsychological tests of pre-morbid IQ, language, attention, speed of processing, frontal executive, visual-perceptual and memory function. Social and medical history was noted by interviews with the twins and a review of the medical records. Results Twin 1 showed mild expressive language difficulties and speed of processing impairments especially on more complex tests of executive function. Her good memory results were discrepant from her experiences of daily living. Twin 2 showed impairment on tests of immediate recall and speed of processing shown by difficulties on tests on executive function. Conclusion The twins performed worst on tests of executive function, which is consistent with other studies. An impaired speed of processing could be contributing to difficulty with more complex tasks. This could also contribute to their experience of poor memory by either affecting encoding or efficient retrieval of information.