Typing competencies in Alzheimer's Disease: an exploration of copy tasks

Background The diagnostic work-up of Alzheimer Disease (AD) is complex, time-consuming, expensive, and quite demanding for the patients. Therefore, there is a growing need for simple non-invasive tools that add to the diagnostic work-up of patients. Objectives This paper investigates a new method for monitoring motor functions in AD using everyday interactions related to writing with a computer, i.c. executing a copy task. Methods An experimental exploratory study was set up in which a carefully designed copy task was presented to three groups of participants: young adults (n = 20), cognitively healthy elderly (n = 20) and age-matched elderly with mild cognitive impairment (MCI) or mild dementia due to AD (n = 12). The task consisted of ten different sub-tasks in which specific bigram characteristics were manipulated. The participants' typing behavior was monitored with keystroke logging. Results The three groups differed significantly from each other in performing the copy task. Typing speed gradually decreased with age. Moreover, the cognitively impaired age-matched adults performed slower on all subtasks expressed in longer interkey intervals within the targeted bigrams. Integrative multilevel modelling showed that all the manipulated bigram characteristics contributed significantly to the model. Conclusion This explorative study shows the potential relevance of using a typing copy task in the diagnostic work-up of patients with neurodegenerative brain disorders. It relates to a natural task, is non-invasive and easy to automatize. In comparison to other motor tasks it allows for fine-grained measurements at an individual level and combines different aspects of complex and fine motor activities in one task.