Semantic impairment in aphasia: A problem of control?

PURPOSE

The relationship between cognitive processes and language ability in aphasia has recently gained increasing attention, with some authors suggesting that control impairments may underlie difficulties with semantic tasks in aphasia. This paper aims to present an overview of the current research on the involvement of cognitive processes in semantic processing tasks and discuss the proposed relationship between cognitive control and semantic processing in aphasia.

METHOD

The role of cognitive processes in semantic processing tasks commonly used in the aphasiology literature is discussed and two theoretical approaches to semantic processing that contribute to the understanding of the nature of semantic breakdown in aphasia are outlined. Finally, we examine the evidence put forward in the Controlled Semantic Cognition framework with regard to the interpretation of impaired performance on semantic processing tasks in people with aphasia.

RESULT

Non-linguistic cognitive abilities such as working memory, inhibition and control are required by semantic processing tasks, in addition to access to conceptual information, making it difficult to dissociate these abilities. Several issues exist regarding the evidence put forward for a control deficit as the underlying cause of poor performance on semantic processing tasks in aphasia.

CONCLUSION

It remains unclear whether impairment on semantic tasks in people with aphasia is related to problems with the representation and/or processing (activation/retrieval) of meaning or problems with cognitive control (or both). Further research is still needed to fully understand how non-linguistic cognitive processes interact with semantic processing, as well as clarify and consistency the definition of control.

Verbal fluency in Alzheimer's disease and mild cognitive impairment in individuals with low educational level and its relationship with reading and writing habits

Verbal fluency (VF) has contributed to building cognitive maps as well as differentiating healthy populations from those with dementia.

Objectives

To compare the performance of healthy controls and patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD) in two semantic VF tasks (animals/clothes) and a phonemic VF task (letter P). Also, to analyze the relationship between the frequency of reading and writing habits (FRWH) and VF in individuals with low educational level.

Methods

Sixty-seven older adults aged 60-80 years and with 2-8 years of schooling were divided into three groups: controls (n=25), older adults with MCI (n=24), and older adults with AD (n=18). We analyzed the type, mean size, and number of clusters, switches, intersections, and returns. A post-hoc single-factor ANOVA analysis was conducted to verify differences between groups.

Results

Total words in the phonemic VF and the animal category discriminated the three groups. Regarding the animal category, AD patients performed worse than controls in the total number of words, taxonomic clusters, returns, and number of words remembered. We found a moderate correlation between FRWH and total number of words in the phonemic fluency.

Conclusions

Semantic (animate) and phonemic (total words) VF differentiated controls and clinical groups from each other - the phonemic component was more related to FRWH than the semantic one. The phonemic VF seems to be more related to cognitive reserve. VF tasks, considering total words and cluster analyses, are a valuable tool to test healthy and cognitively impaired older adults who have a low educational level.

Naming and verbal learning in adults with Alzheimer's disease, mild cognitive impairment and in healthy aging, with low educational levels

Language assessment seems to be an effective tool to differentiate healthy and cognitively impaired aging groups. This article discusses the impact of educational level on a naming task, on a verbal learning with semantic cues task and on the MMSE in healthy aging adults at three educational levels (very low, low and high) as well as comparing two clinical groups of very low (0-3 years) and low education (4-7 years) patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI) with healthy controls. The participants comprised 101 healthy controls, 17 patients with MCI and 19 with AD. Comparisons between the healthy groups showed an education effect on the MMSE, but not on naming and verbal learning. However, the clinical groups were differentiated in both the naming and verbal learning assessment. The results support the assumption that the verbal learning with semantic cues task is a valid tool to diagnose MCI and AD patients, with no influence from education.

Mammary and extramammary Paget's disease: an immunohistochemical study of 83 cases

AIM

Mammary Paget's disease (MPD) and extramammary Paget's disease (EMPD) are rare neoplasms. The aim of this study was, by the use of immunohistochemistry, to derive further information about the cell(s) of origin, find a diagnostically useful immunohistochemical panel and investigate candidates for possible targeted therapy.

MATERIAL AND RESULTS

Sixty MPD and 23 EMPD cases were studied using antibodies to cytokeratin (CK) 34betaE12, CK8/18, CK7, CK5/6, CK20, gross cyctic disease fluid protein (GCDFP)-15, MUC1-8, epidermal growth factor receptor (EGFR) (HER1), HER3 and HER4. In all MPD cases CK7 and MUC1 were positive. CK8/18 was positive in 59/60 cases. GCDFP-15, MUC2, MUC3, MUC4, MUC7, MUC8 were positive in 29/60, 3/60, 35/47, 4/40, 3/43 and 2/45 cases, respectively. In all EMPD cases CK8/18 and CK7 were positive. MUC1, GCDFP-15, MUC5AC, MUC3, MUC8 and CK20 were positive in 22/23, 19/23, 8/19, 3/19, 1/19 and 3/23 cases, respectively. With the remaining antibodies no immunoreactivity was observed.

CONCLUSION

MUC1 and low-molecular-weight CKs in conjunction with immunonegativity for high-molecular-weight CKs are the most diagnostically useful markers. MPD is caused by the epidermotropic spread of underlying tumour cells, whereas EMPD probably arises from intraepithelial cells of sweat gland origin. Targeted therapy with antibodies against EGFR (HER1), HER3 or HER4 is unlikely to prove of clinical value.