Background
Animal fluency is a widely used task to assess people with Alzheimer’s disease (AD) and other neurological disorders. The mechanisms that drive performance in this task are argued to rely on language and executive functions. However, there is little information regarding what specific aspects of these cognitive processes drive performance on this task.
Objective
To understand which aspects of language (i.e., semantics, phonological output lexicon, phonological assembly) and executive function (i.e., mental set shifting; information updating and monitoring; inhibition of possible responses) are involved in the performance of animal fluency in people with AD.
Methods
Animal fluency data from 58 people with probable AD from the DementiaBank Pittsburgh Corpus were analyzed. Number of clusters and switches were measured and nine word properties (e.g., frequency, familiarity) for each of the correct words (i.e., each word counting toward the total score, disregarding non-animals and repetitions) were determined. Random forests were used to understand which variables predicted the total number of correct words, and conditional inference trees were used to search for interactions between the variables. Finally, Wilcoxon tests were implemented to cross-validate the results, by comparing the performance of participants with scores below the norm in animal fluency against participants with scores within the norm based on a large normative sample.
Results
Switches and age of acquisition emerged as the most important variables to predict total number of correct words in animal fluency in people with AD. Cross-validating the results, people with AD whose animal fluency scores fell below the norm produced fewer switches and words with lower age of acquisition than people with AD with scores in the normal range.
Conclusion
The results indicate that people with AD rely on executive functioning (information updating and monitoring) and language (phonological output lexicon, not necessarily semantics) to produce words on animal fluency.
Background: Several studies using musical elements in the treatment of neurological language and speech disorders have reported improvement of speech production. One such programme, Speech-Music Therapy for Aphasia (SMTA), integrates speech therapy and music therapy (MT) to treat the individual with Apraxia of Speech (AoS) and aphasia. We have observed encouraging results in clinical practice, but there is still no empirical evidence of the effect of SMTA. Aims: The current study investigated the effectiveness of SMTA on verbal communication in daily life. Methods & Procedures: Five participants with AoS accompanied by aphasia were included in an efficacy study using a case series design with multiple measurements. All participants received 24 SMTA sessions including two 30-min sessions per week. Pretreatment and posttreatment (immediately and 3 months after treatment stopped), verbal communication (intelligibility and comprehensibility) were tested with the Amsterdam-Nijmegen Everyday Language Test. The Aachen Aphasia Test (AAT) and the Diagnostic Instrument for Apraxia of Speech (DIAS) were also administered. The participants were tested four times before the start of the treatment (baseline) with a related test for progress on articulation (Modified Diadochokinesis Test (MDT)) and once with an unrelated control test (Psycholinguistic Assessment in Language Processing of Aphasia 12; repetition of number series). During the treatment, both tests were administered weekly. Outcomes & Results: Intelligibility of verbal communication for all participating individuals, as well as comprehensibility in four out of five participants, improved after 24 SMTA treatment sessions. All measures of MDT and repetition of AAT showed significant improvement for all participants. Four participants also improved on the test for articulation of phonemes and the diadochokinesis test of the DIAS. Furthermore, two participants improved on the articulation of words (DIAS). The improvement remained stable after treatment ended (follow-up). For three out of the five participants, no improvement was found on the control tests. Two participants also showed improvement on almost all outcome measures, but also improved on the control tests. SMTA not only affected articulation but also positively influenced the severity of the aphasia in four out of five participants. Conclusions: SMTA seems an effective treatment programme for at least three of the five individuals that were treated in the current study. This treatment led not only to better articulation, but more importantly, also to improvement in communication in daily life.
In the current ERP study, an active oddball task was carried out, testing pure tones and auditory, visual and audiovisual syllables. For pure tones, an MMN, an N2b, and a P3 were found, confirming traditional findings. Auditory syllables evoked an N2 and a P3. We found that the amplitude of the P3 depended on the distance between standard and deviant. A smaller distance required more attention, which was reflected in a larger amplitude. An analysis of audiovisual material, after correction for visual activity, showed that McGurk type stimuli evoked brain responses that differed from both the standard and the congruent deviants. Finally, we found that congruent audiovisual stimuli elicited an N2 with a shorter latency and a P3 with a smaller amplitude than auditory stimuli. The current ERP study, thus, shows that for audiovisual processing the whole is more than the sum of its parts.
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