P300 and Neuropsychological Assessment in Mild Cognitive Impairment and Alzheimer Dementia

Abstract

Only a small proportion of individuals with Mild Cognitive Impairment (MCI) will convert to dementia. Methods currently available to identify risk for conversion do not combine enough sensitivity and specificity, which is even more problematic in low-educated populations. Current guidelines suggest the use of combined markers for dementia to enhance the prediction accuracy of assessment methods. The present study adhered to this proposal and investigated the sensitivity and specificity of the electrophysiological component P300 and standard neuropsychological tests to assess patients with Alzheimer’s disease (AD) and MCI recruited from a low-income country. The neuropsychological battery comprised tests of memory, attention, language, praxis, and executive functions. The P300 was recorded using a classical visual odd-ball paradigm. Three variables were found to achieve sensitivity and specificity values above 80% (Immediate and Delayed recall of word list – CERAD – and the latency of P300) for both MCI and AD. When they entered the model together (i.e., combined approach) the sensitivity for MCI increased to 96% and the specificity remained high (80%). Our preliminary findings suggest that the combined use of sensitive neuropsychological tasks and the analysis of the P300 may offer a very useful method for the preclinical assessment of AD, particularly in populations with low socioeconomic and educational levels. Our results provide a platform and justification to employ more resources to convert P300 and related parameters into a biological marker for AD.

The Role of Physical Fitness in the Neurocognitive Performance of Task Switching in Older Persons with Mild Cognitive Impairment

“…Previous studies have suggested that elderly people with MCI have lower executive functioning compared to age-matched controls, leading to less efficient inhibitory control and working memory [21,33]. In the present study the accuracy rates and RTs in the homogeneous condition for the aMCI subjects did not differ significantly from those of the controls, a result that is in agreement with Belleville et al's [33] findings, indicating that people with aMCI have no particular problem in managing such tasks in isolation.…”

“…Previous research reported that the P3 latency was stable and sensitive in cognitive evaluations of MCI patients and those with conversion from MCI to AD [23]. Indeed, a number of experimental studies also demonstrated prolonged P3 latency in the elderly with aMCI [21,72] and MCI [73][74][75] when performing the visual and auditory oddball tasks. Therefore, in support of these earlier findings, the prolonged P3 latency found in the current paper seems to be a neuropathological characteristic of MCI.…”

“…There is a growing body of research that supports the presence of an early executive functioning deficit in persons with aMCI [21,29,[33][34][35]. Task switching is an executive function that is needed to master a wide array of daily tasks, and thus is suitable for examining age-related effects on the abilities to represent, maintain, and update contextual information in working memory [36].…”

“…Several reports over the past decade described the potential diagnostic importance of electrophysiological markers of cognitive decline in patients with MCI and the preclinical stage of AD, as obtained by analysis of the electroencephalography-derived event-related potentials (ERPs) [20][21][22][23][24][25][26][27][28][29]. For example, the ERP P2, N2, and P3 components are recognized as effective electrophysiological indices in the early stage of MCI diagnosis [20][21][22][23], as MCI subjects have prolonged P2, N2, and P3 latencies, and reduced P3 amplitudes, compared to healthy elderly controls [20,[24][25][26]. Even specific to the MCI subgroups [e.g., amnestic MCI (aMCI)], these ERP components may also be useful for observing the differences in cognitive processes from those of the healthy elderly [20,24,27,28], and to distinguish the different MCI subtypes (e.g., aMCI versus nonaMCI) [29].…”

Altered neurocognitive processing of tactile stimuli in patients with Complex Regional Pain Syndrome (CRPS)

“…A rationale for investigating the P300 is its potential as a robust biomarker of cognitive dysfunction. For example, EEG research in other clinical contexts has found that P300 marks cognitive dysfunction in chronic headache 11 , chronic lower back pain 12 , phantom limb pain 13 , schizophrenia 14 , disorders of consciousness 15 and dementia 16 . The P300 is thought to reflect cognitive updating processes that are sensitive to task demands (providing a marker of attentional resource allocation).…”