Are There Any Connections between Language Deficits and Cognitive Slowing in Alzheimer's Disease?

The scope of using pragmatic language tests for early detection of dementia: A systematic review of investigations using figurative language

INTRODUCTION

Dementia cases are expected to rise to 81.1 million in 2040. Efforts are underway to develop diagnostic methods to facilitate early detection of the disease. Herein we review research findings focusing on pragmatic dysfunction in patients with dementia and evaluate the usefulness of assessing dementia and its progress with a battery of tests assessing figurative language skills.

METHODS

A total of 74,778 article titles were identified from EMBASE, PubMed, and Google Scholar databases. After systematic screening, 51 journal articles were selected for the final review.

RESULT

The review suggests that impaired figurative language might be a marker for early cognitive decline. Different forms of figurative language may be impaired at different stages of the disease and in different types of dementia involving different neuropathologies.

CONCLUSION

The use of pragmatic tests in combination with the existing diagnostic protocols might increase the probability of early diagnosis. HIGHLIGHTS Pragmatic impairment could be a marker of early cognitive impairment. Figurative language-an important pragmatic aspect-is disrupted in mild cognitive impairment (MCI) and early Alzheimer's disease (AD). Figurative language impairment might precede literal language impairment. Pragmatic tests could be more sensitive than standard neuropsychological tests. Inclusion of pragmatic tests in diagnostic guidelines might bolster early detection.

Supporting auditory word recognition with transcranial direct current stimulation: effects in elderly individuals with and without objective memory complaints

Healthy elderly people often experience a subjective loss of daily memory performance whereas an objective decrease in memory performance is often observed in patients with memory complaints. In this paper, we investigate the influence of a single session of "anodal" transcranial direct current stimulation (a-tDCS) on auditory word recognition performance in a decision time experiment. Three groups of participants (>64 years of age) with and without memory complaints underwent a word recognition task, in which they had to recognize words previously encoded among several distractors (semantically or phonologically related words) via a button press. In this double-blinded study, the participants completed two sessions (sham/a-tDCS), counterbalanced between subjects with a washout period of at least 10 days. Twenty minutes of 1.5 mA a-tDCS was applied over the left temporal cortex during the memorizing and decision phases. Overall, our results demonstrated that the participants, independent of their memory performance, were faster in word recognition during a-tDCS. As expected, older participants with memory complaints recognized significantly less words correctly compared to other participants. However, tDCS did not have a beneficial effect on the extent of successful word recognition. These results suggest a general effect of a single session of a-tDCS over the left temporal cortex, with participants becoming faster in their word recognition, thus having easier access to encoded words.