Lexical processing in Spanish patients with probable Alzheimer’s disease

The NeuroBel: A Screening Test for Verbal Language Impairment in Spanish-Speaking Elderly People With Cognitive Decline

PURPOSE

The NeuroBel is a short test that can detect cognitive decline using language tasks. This study replicated previous research using larger clinical samples from three Spanish-speaking countries.

METHOD

Eight tasks were used to analyze verbal language functioning using a psycholinguistic approach. A total of 232 elderly, monolingual Spanish speakers from Spain, Cuba, and Colombia participated in this study. Of these, 76 had Alzheimer's disease (AD) in the initial phase, 75 had mild cognitive impairment (MCI), and 81 did not exhibit cognitive impairment (healthy controls).

RESULTS

Significant differences were observed among the three clinical groups. The participants with AD and the participants with MCI had significantly lower NeuroBel scores than the control group on most of the tasks. However, repetition (in AD vs. MCI) and auditory lexical decision (in MCI vs. control) tasks were not significant in Tukey's post hoc tests. Discriminant analysis showed that 80.6% of the participants were correctly classified into the original groups and revealed the tasks that were the best and worst for differentiating among groups. The receiver-operating characteristic curves showed high sensitivity for AD and MCI. The area under the curve was .97 in the contrast of AD versus MCI + controls, .96 in the determination of overall cognitive decline (AD + MCI vs. controls), and .93 in the contrast of MCI and control groups.

CONCLUSION

This study confirmed that the NeuroBel is a suitable test for detecting cognitive decline based on language impairment in Spanish-speaking elderly people.

Reading Fluency in Spanish Patients with Alzheimer's Disease

BACKGROUND

Reading fluency is essential for our functioning in the literate society in which we live. Reading expressiveness or prosody, along with speed and accuracy, are considered key aspects of fluent reading. Prosodic patterns may vary, not being the same in children learning to read as in adulthood. But little is known about the prosodic characteristics and reading fluency of people with neurodegenerative diseases that causes language impairment and reading difficulties, such as Alzheimer's disease (AD).

OBJECTIVE

The aim of this work was to study reading fluency in AD, considering reading speed, accuracy and reading prosody.

METHODS

The participants were 20 healthy elderly Spanish adults, and 20 AD patients, aged 64-88 years. An experimental text was designed, that included declarative, exclamatory, and interrogative sentences, words with different stresses and low-frequency words. The reading of the participants was recorded and analyzed using Praat software.

RESULTS

The AD group showed significantly longer reading duration, both at the syllable level and at the word and sentence level. These patients also committed more pauses between words, which were also longer, and more reading errors. The control group showed a variation of the syllabic F0 in the three types of sentences, while these variations only appeared in declarative ones in the AD group.

CONCLUSION

The pauses, along with the slight pitch variations and the longer reading times and errors committed, compromise the reading fluency of people with AD. Assessment of this reading feature could be interesting as a possible diagnostic marker for the disease.

Evolution of Writing Impairment in Spanish Patients with Alzheimer's Disease

BACKGROUND

Although some studies suggest that writing difficulties may be one of the early symptoms of Alzheimer's disease (AD), they have been scarcely studied compared to oral language. Particularly noteworthy is the paucity of longitudinal studies that enable the observation of writing impairment as cognitive decline progresses.

OBJECTIVE

The aim of this study was to examine the characteristics of writing in patients with AD and to monitor the deterioration of their performance over a follow-up period.

METHODS

Sixty-four participants (half with AD and half healthy elderly) were compared in a word and pseudo-word dictation task. Patients were evaluated every 6 months over a 2.5 year follow-up period.

RESULTS

The evolution of patient performance and error profile shows a typical pattern of deterioration, with early damage to the lexical pathway, which later extends to the phonological pathway and eventually affects peripheral processes.

CONCLUSION

These results confirm the presence of writing difficulties from the early stages of AD, supporting the value of this task for early diagnosis. Furthermore, it allows us to explain the contradictory data obtained in previous investigations.

Accuracy of verbal fluency tests in the discrimination of mild cognitive impairment and probable Alzheimer's disease in older Spanish monolingual individuals

The main objetive was to analyze the accuracy of different verbal fluency tests (VFTs) in discriminating cognitively healthy subjects from individuals with mild cognitive impairment (MCI) and probable Alzheimer's disease (AD) in a cohort of older Spanish speaking adults. As a result, we aimed to identify the VFT that best predicts conversion from MCI to probable AD. 287 subjects: 170 controls (HC), 90 stable MCI and 27 patients with MCI that evolved into probable AD (MCI-AD) were assessed with a neuropsychological battery test and five VFTs. The animal fluency test produced the best differentiation of HC from MCI (p < .001), of HC from MCI-AD (p < .001) and of MCI from MCI-AD converters (p < .001), with sensitivities 98.8%, 98.8% and 75.6%, respectively. Logistic regression showed that the animal fluency test (p < 0.001) appears to be the most useful and neuropsychological VFT to predict conversion to probable dementia.

NeuroBel: Spanish screening test for oral psycholinguistics disabilities in elderly people with mild cognitive impairment and early-stage Alzheimer's disease

INTRODUCTION

The NeuroBel is a short test that allows for psycholinguistic assessment of basic processes of oral comprehension and language production deterioration in the elderly. The objective is to carry out a pilot study of the initial reference values and cut-off points of this battery using a sample of Spanish elderly adults, with and without cognitive impairment, and detecting performance differences among them.

METHOD

NeuroBel consists of 8 tasks that analyze oral language functioning from the theoretical model proposed by the Psycholinguistic approach. Seventy-five Spanish monolingual adult-elderly participants of both genders. Of those, 25 with Alzheimer's disease (AD) in the initial phase, 25 with mild cognitive impairment (MCI) and 25 participants without cognitive impairment (Controls). All subjects were evaluated using NeuroBel.

RESULTS

There are significant differences between the three groups. The participants with AD are significantly worse in the total score of NeuroBel. A discriminant analysis shows that 86.7% of the cases appear correctly classified in the groups originally selected. Likewise, participants with MCI obtained results that are statistically significantly worse than the control group. NeuroBel shows a high correlation with the MMSE (.89) and Sensitivity (.96) in the determination of AD and cognitive deterioration (AD + MCI vs. Controls). The area under the ROC curve is .97 in the contrast of AD vs. Controls and .98 in the determination of cognitive deterioration (AD + MCI vs. Controls). The canonical discriminant functions and the precision cut-offs from the ROC analyses are also shown in the results.

CONCLUSIONS

NeuroBel is shown as a "very good" test in the detection of cognitive-linguistic impairment in elderly-adults.

A Comparative Single-Blind Randomized Controlled Trial With Language Training in People With Mild Cognitive Impairment

BACKGROUND

Although cognitive training is effective for people with mild cognitive impairment (MCI), it is not clear which format is more effective.

OBJECTIVE

To compare the effectiveness of the same language programs when carried out via computer, paper/pencil and orally in people with MCI.

METHODS

Seventy-one participants with MCI were randomly classified in 3 experimental and 2 control groups. The experimental groups attended 48 sessions of language training for 6 months. The control groups attended either unstructured sessions or they were on waiting list.

RESULTS

Mixed measures analysis of variance, at the follow-up, showed a significant cognitive abilities improvement among the experimental versus control groups. At the end of the language training, the 3 groups presented improvement in cognitive abilities and daily function, while the control groups remained at the same performance level.

CONCLUSION

All 3 cognitive language training methods were equally significantly effective.

Temporal parameters of spontaneous speech in Alzheimer's disease

This paper reports on four temporal parameters of spontaneous speech in three stages of Alzheimer's disease (mild, moderate, and severe) compared to age-matched normal controls. The analysis of the time course of speech has been shown to be a particularly sensitive neuropsychological method to investigate cognitive processes such as speech planning and production. The following parameters of speech were measured in Hungarian native-speakers with Alzheimer's disease and normal controls: articulation rate, speech tempo, hesitation ratio, and rate of grammatical errors. Results revealed significant differences in most of these speech parameters among the three Alzheimer's disease groups. Additionally, the clearest difference between the normal control group and the mild Alzheimer's disease group involved the hesitation ratio, which was significantly higher in the latter group. This parameter of speech may have diagnostic value for mild-stage Alzheimer's disease and therefore could be a useful aid in medical practice.

Learning and forgetting new names and objects in MCI and AD

We studied how subjects with mild cognitive impairment (MCI), early Alzheimer's disease (AD) and age-matched controls learned and maintained the names of unfamiliar objects that were trained with or without semantic support (object definitions). Naming performance, phonological cueing, incidental learning of the definitions and recognition of the objects were tested during follow-up. We found that word learning was significantly impaired in MCI and AD patients, whereas forgetting patterns were similar across groups. Semantic support showed a beneficial effect on object name retrieval in the MCI group 8 weeks after training, suggesting that the MCI patients' preserved semantic memory can compensate for impaired episodic memory. The MCI group performed equally well as the controls in the tasks measuring incidental learning and recognition memory, whereas the AD group showed impairment in this respect. Both the MCI and the AD group benefited less from phonological cueing than the controls. Our findings indicate that word learning is compromised in both MCI and AD, whereas long-term retention of newly learned words is not affected to the same extent. Incidental learning and recognition memory seem to be well preserved in MCI.

Evidence for linguistic deficit in nonlexical processing in reading. A study of a Spanish-speaking patient

Previous studies have shown that in the so-called opaque languages (those in which spelling does not correspond to pronunciation), there are relatively independent routes for lexical and nonlexical processing, that is, for words and nonwords, both in spoken and in written language. On the other hand, in the so-called transparent languages (those in which pronunciation corresponds to written forms), empirical evidence is scarcer. In this study of a neurological patient (parieto-temporal lesion), speaker of a transparent language (Spanish) showing a specific deficit in nonlexical reading processing, linguistic analysis for words was relatively preserved. This finding suggests the use of various routes in the processing of transparent languages.

Cognitive changes in the preclinical phase of familial Alzheimer's disease

Few studies have examined the presence of linguistic deficits in the preclinical phase of Alzheimer's disease (AD). A total of 19 healthy carriers of the E280A presenilin-1 gene mutation in chromosome 14 and 21 noncarrier family members from Antioquia, Colombia, were administered a neurolinguistic evaluation of lexical-semantic processes. Both groups were similar in age, educational level, and gender. Carriers scored significantly lower than noncarriers on naming of famous faces. Cognitive changes in lexical-semantic tasks can be detected before the clinical diagnosis of probable familial AD, and a neurolinguistic evaluation may be a useful tool in the early clinical diagnosis of sporadic AD as well.