Hanna Steinunn Steingrimsdottir

Identity matching in a patient with Alzheimer's disease.

Difficulties with short-term memory are one of the main problems in patients with dementia. Therefore, one purpose of this study was to examine the effects of simultaneous vs delayed presentation of comparison stimuli in a matching-to-sample (MTS) task using computerized training. By using an identity MTS procedure, the participant was trained to select a comparison stimulus identical to a sample stimulus. A 2nd purpose was to study the effect of the number of choices presented, thereby evaluating short-term memory deficits and possible deterioration of deficits over time. In this study, an 80-year-old-male with a Mini-Mental State Examination (MMSE) score of 10 was exposed to 4 experimental conditions. The results showed that using 3 comparison stimuli presented simultaneously with the sample stimulus on the screen resulted in more incorrect responding than when using 2 comparison stimuli. Furthermore, when adding a 0-second delay between the presentation of the sample stimulus and the 2 comparison stimuli, the number of correct responses did not exceed chance level.

On the utility of within-participant research design when working with patients with neurocognitive disorders.

Within-participant research designs are frequently used within the field of behavior analysis to document changes in behavior before, during, and after treatment. The purpose of the present article is to show the utility of within-participant research designs when working with older adults with neurocognitive disorders. The reason for advocating for these types of experimental designs is that they provide valid information about whether the changes that are observed in the dependent variable are caused by manipulations of the independent variable, or whether the change may be due to other variables. We provide examples from published papers where within-participant research design has been used with patients with neurocognitive disorders. The examples vary somewhat, demonstrating possible applications. It is our suggestion that the within-participant research design may be used more often with the targeted client group than is documented in the literature at the current date.

Electroencephalography (EEG) in the Study of Equivalence Class Formation. An Explorative Study

Teaching arbitrary conditional discriminations and testing for derived relations may be essential for understanding changes in cognitive skills. Such conditional discrimination procedures are often used within stimulus equivalence research. For example, the participant is taught AB and BC relations and tested if emergent relations as BA, CB, AC and CA occur. The purpose of the current explorative experiment was to study stimulus equivalence class formation in older adults with electroencephalography (EEG) recordings as an additional measure. The EEG was used to learn about whether there was an indication of cognitive changes such as those observed in neurocognitive disorders (NCD). The present study included four participants who did conditional discrimination training and testing. The experimental design employed pre-class formation sorting and post-class formation sorting of the stimuli used in the experiment. EEG recordings were conducted before training, after training and after testing. The results showed that two participants formed equivalence classes, one participant failed in one of the three test relations, and one participant failed in two of the three test relations. This fourth participant also failed to sort the stimuli in accordance with the experimenter-defined stimulus equivalence classes during post-class formation sorting. The EEG indicated no cognitive decline in the first three participants but possible mild cognitive impairment (MCI) in the fourth participant. The results suggest that equivalence class formation may provide information about cognitive impairments such as those that are likely to occur in the early stages of NCD. The study recommends replications with broader samples.