Preserved morphological decomposition in persons with Alzheimer's disease

Sentence comprehension in Slovak-speaking patients with Alzheimer's disease

BACKGROUND

According to some studies, sentence comprehension is diminished in Alzheimer's disease (AD) patients, but they differ on what underlies the sentence comprehension impairment. Sentence comprehension in AD patients has been studied mainly in the English language. It is less clear how patients with AD speaking a morphologically rich language with grammatical morphemes indicating case and through it even thematic roles process reversible sentences.

AIMS

To compare the comprehension of various syntactic constructions in Slovak-speaking AD patients and cognitively intact elderly people. We were concerned with the influence of the following aspects on sentence comprehension: its length, the order of thematic roles and the presence of a morphological cue placed on the first noun (or at the beginning of a sentence).

METHODS & PROCEDURES

We used our own Slovak test of sentence comprehension based on matching pictures to spoken sentences. These sentences contain transitive verbs and two nouns (person/animal), one functioning as a subject and the other as an object, which both can perform the action expressed by the verb. We assessed 62 healthy elderly people and two groups of AD patients. The first group consisted of 34 participants with a mild degree of AD and the other group of 43 participants with a moderate degree of AD.

OUTCOME & RESULTS

Statistical comparisons showed that the elderly controls were significantly better in the comprehension of simple active OVS (object-verb-subject word order) sentences and complex EO sentences (a centre-embedded relative clause with a relative pronoun substituting for an object) than patients with a mild degree of AD. In patients with a moderate degree of AD, comprehension of all tested sentence types was worse than in healthy elderly people. The results also indicated that even mild AD patients have more serious problems with processing sentences with non-canonical order of thematic roles regardless of a morphological cue at the beginning of a sentence.

CONCLUSION & IMPLICATIONS

The results point to diminished sentence comprehension in patients with AD. In the group of mild AD patients, the order of thematic roles played a significant role in their sentence comprehension. Even though the grammatical morphemes clearly code the functions of words in the Slovak language, mild AD patients do not process them in sentences with a non-canonical order of thematic roles at the same level as the healthy controls. Patients with moderate AD have significant problems even with the comprehension of sentences with a canonical order of thematic roles. These difficulties seem to be a consequence of insufficient resources for language processing.

Language Disorders in Multilingual and Multicultural Populations

We review the characteristics of developmental language disorders (primary language impairment, reading disorders, autism, Down syndrome) and acquired language disorders (aphasia, dementia, traumatic brain injury) among multilingual and multicultural individuals. We highlight the unique assessment and treatment considerations pertinent to this population, including, for example, concerns of language choice and availability of measures and of normative data in multiple languages. A summary of relevant, recent research studies is provided for each of the language disorders selected.

The processing of morphology in old age: evidence from Hebrew

PURPOSE

Taking advantage of the rich morphological structure of Hebrew, the current article aims to examine whether age affects the processing of morphological forms through an investigation of 2 systematic morphological paradigms.

METHOD

Forty-eight young and 48 old Hebrew speakers completed 2 experiments: the 1st investigated sensitivity to subject-verb gender incongruity in a reading task, and the 2nd examined parsing of pseudoverbs containing existing and nonexisting consonantal roots in a lexical-decision task.

RESULTS

Older adults were slower relative to the young, but both groups were slower on incongruent relative to congruent targets and on a pseudoverb with a real root relative to a pseudoverb with a nonexistent root. In both experiments the interaction between condition and age was statistically significant.

CONCLUSIONS

While older adults demonstrate preserved morphological parsing abilities, possible explanations for the interaction effect include cognitive slowing or deficient inhibitory control.