Semantic Memory as an Early Cognitive Marker of Alzheimer's Disease: Role of Category and Phonological Verbal Fluency Tasks

Background: The assessment of semantic memory may be a useful marker to identify individuals with mild cognitive impairment (MCI) who will progress to Alzheimer's disease (AD) in the early stages of the disease. Objective: The aim of this five-year follow-up longitudinal study is to assess whether semantic assessment could predict progression in MCI. Methods: A population of MCI (N = 251); mild (N = 178) and moderate AD (N = 114); and a sample of healthy participants (HP; N = 262) was investigated. The five-year follow-up of the MCI group was completed by 178 patients. Semantic and episodic memory measures were used, including a measure of the discrepancy between categorical and phonological verbal fluency, the semantic-phonological delta (SPD). The main outcome was the progression of MCI due to AD to dementia. Results: A general linear model showed a significant effect of diagnosis on SPD (Wilks' Lambda = 0.591; p < 0.001). The estimated marginal means were -0.91 (SE = 0.185) in HP, -1.83 (SE = 0.187) in MCI, -1.16 (SE = 0.218) in mild AD, and -1.02 (SE = 0.275) in moderate AD. Post-hoc comparisons showed a significant difference between MCI and HP (p < 0.001). The follow-up was completed by 178 MCI individuals. SPD in MCI patients who progress to dementia was significantly lower than in MCI that will not progress (p = 0.003). Together with the Mini-Mental State Examination, the SPD was the only measure with a significant predicting effect at the five-years follow-up (p = 0.016). Conclusion: The SPD indicate the impairment of semantic memory in individuals with underlying AD at the MCI early stage, reflecting the early involvement of perirhinal and entorhinal cortices in the earliest stages of AD neuropathological process

Does Hearing Loss in the Elderly Individuals Conform to Impairment of Specific Cognitive Domains?

BACKGROUND: It is well known that age-related hearing loss (ARHL) is strongly associated with dementia. Different hypotheses have been considered to explain this link, including sensorial deprivation, the reduction in cognitive reserve, and the presence of shared pathological pathways (microvascular damage of the brain). AIMS: We carried out a study of the audiological and neuropsychological characteristics of a sample of hearing impaired but cognitively healthy individuals (HIH). The aim of our study was to carefully outline the neuropsychological profile of the patients in order to verify whether hearing loss correlated with deficits in specific cognitive domains. RESULTS: Episodic memory is affected by the presence of hearing loss, while semantic competences, syntactic, and grammar skills seem not to be affected. Furthermore, some audiological features linked to the intelligibility of spoken words can predict the presence of executive dysfunction; the same does not apply to memory impairment. CONCLUSION: In HIH, executive functions are widely employed in maintaining an acceptable level of comprehension of spoken language; consequently, other cognitive domains and instrumental abilities in HIH are not properly supported. Thus, it is arguable that programs of hearing rehabilitation for HIH could restore the allocation of attentional resources to the functioning of other cognitive domains

The instruments used by the Italian centres for cognitive disorders and dementia to diagnose mild cognitive impairment (MCI)

Aims: The purpose of this study was to examine the tools used in Italy to diagnose mild cognitive impairment (MCI). Methods: In collaboration with the Luigi Amaducci Research Consortium, the Italian Network of Alzheimer Evaluation Units prepared a questionnaire to describe how MCI is diagnosed in the Italian Centres for cognitive disorders and dementia (CCDD). Results: Most of the ninety-two CCDDs participating in the survey were located in hospitals (54.7%); large percentages were coordinated by neurologists (50.8%) and geriatricians (44.6%). Almost all (98.5%) used the Mini Mental State Examination to diagnose MCI; the Clock Drawing Test was also frequently used (83.9%). Other neuropsychological, imaging and biomarker tests were utilized less frequently and a wide diversity in the instruments used was noted. Conclusions: According to the results, diagnoses of MCI are based on a multitude of instruments, with major differences in the clinical assessment of geriatricians and neurologists. Standardized testing protocols, validated instruments and cut-off points need to be identified and adopted by the CCDDs for assessing MCI