Verbal Fluency Deficits Co-Occur with Memory Deficits in Geriatric Patients at Risk for Dementia: Implications for the Concept of Mild Cognitive Impairment

Abstract

Abstract. We tested the notion that patients at high risk for progression to Alzheimer's disease (AD) display relatively isolated memory deficits by assessing the relationship between memory and fluency performances in a sample of 92 geriatric subjects with cognitive complaints and normal to mild clinical presentations. Patient groups were formed on the basis of memory test scores. Patients with normal memory scores also performed normally on fluency tests, and their fluency scores were significantly higher than those of patients with low memory performances. Patients falling between these two groups in memory abilities also displayed intermediate level fluency performances. Whereas the normal memory group performed at equivalent levels on semantic and phonemic fluency tasks, both the impaired memory group and the intermediate group displayed relatively greater weaknesses in semantic fluency. This pattern is similar to that seen in AD. Since the impaired memory patients meet criteria for Amnestic Mild Cognitive Impairment, these findings suggest that memory deficits in "pre-clinical" AD are likely to be accompanied by fluency weaknesses, with semantic fluency weaknesses predominating.

APOE,MAPT, andSNCAGenes and Cognitive Performance in Parkinson Disease

“…However, impairment in semantic fluency, with relative sparing of phonemic fluency, also occurs. 27,28 This observation is attributed to the fact that temporal cortex, one of the first brain regions affected in AD, 29,30 plays a larger role in mediating semantic than phonemic verbal fluency. 31 In contrast, early cognitive deficits in PD usually involve attention and frontal-executive function mediated in part by cortical-striatal dopamine deficiency, though some patients do initially exhibit isolated deficits in other domains.…”

The Safety, Tolerability, and Efficacy of Once-Daily Memantine (28 mg): A Multinational, Randomized, Double-Blind, Placebo-Controlled Trial in Patients with Moderate-to-Severe Alzheimer’s Disease Taking Cholinesterase Inhibitors

“…The semantic fluency task requires attention, information retrieval, and intact semantic associations [35–37], and is strongly dependent upon the hippocampus and related structures in the left mediotemporal lobe [38, 39]. In patients with AD, semantic fluency positively correlates with measures of memory [40] and the ability to perform everyday activities [35]. …”

Semantic and Phonemic Verbal Fluency Discrepancy in Mild Cognitive Impairment: Potential Predictor of Progression to Alzheimer's Disease

“…Verbal fluency tests have the advantages of ease and brevity of administration, which make them suitable as bedside tests for assessment of possible cognitive decline . Semantic verbal fluency (retrieval of words in a specified category, e.g., animals) and phonemic fluency (retrieval of words starting with a specified letter of the alphabet) both reflect executive functioning, and frontal lesions impair performance on both tests to a similar degree, but semantic tests have an additional semantic memory component, and temporal lobe lesions such as those in AD result in greater impairment in semantic fluency than in phonemic fluency .…”

“…Studies of relative semantic‐phonemic discrepancies in MCI have yielded discordant results. Most studies have demonstrated poorer semantic than phonemic fluency in individuals MCI than in normal controls, but others have shown similar patterns in phonemic‐semantic verbal fluency discrepancy scores in individuals with amnestic MCI and controls, although these studies were limited by small sample size. Whether discrepancy scores are useful in predicting who will progress to AD has not been well studied.…”