Using informative verbal exchanges to promote verb retrieval in nonfluent aphasia.

PURPOSE: The goal of this study was to determine whether positive treatment effects of a modified constraint-induced language therapy focused on verb production would generalize to unpracticed items and tasks. METHOD: Four individuals participated in a single-subject treatment design protocol. The treatment involved intensive practice producing verbs in sentences in an informative communicative exchange. Direct treatment outcome was examined by measuring the accuracy of producing practiced verbs in an action description task, a task similar to those used in treatment. Generalization was assessed by measuring production of unpracticed verbs and sentence grammaticality in the action description task and by measuring verb production and sentence grammaticality in 2 relatively unstructured (unpracticed) language tasks. RESULTS: Two of the 4 participants showed a direct treatment effect, producing a greater number of practiced verbs in the action description task following treatment compared with before treatment. All participants improved sentence grammaticality following treatment, although grammaticality was not explicitly targeted in therapy. Generalization to unpracticed, less-structured tasks was variable across the participants. CONCLUSION: Patterns of generalization may depend on participants' specific language deficits and production characteristics, on the language tasks used, and on the measures used to detect change and assess generalization.

Assessment of neglect dyslexia with functional reading materials.

BACKGROUND: Spatial neglect is a neurocognitive disorder that affects perception, representation, and/or motor planning. Neglect dyslexia in spatial neglect after right hemisphere damage may co-occur with, or be dissociated from, other spatial neglect signs. Previous neglect dyslexia research focused on word-level stimuli and reading errors. Using single words for assessment may leave some people with neglect dyslexia undiagnosed, and assessment materials that are closer to texts read in real life may better capture neglect dyslexia. METHOD: The authors tested reading in 67 right hemisphere stroke survivors with 4 types of text materials: words, phrases, an article, and a menu. RESULTS: Accuracy on reading the menu and article texts was significantly poorer than reading the words and phrases. The hypothesis that assessment materials with ecological validity such as reading a menu and reading an article may be more challenging than reading single words and phrases was supported. CONCLUSION: Results suggest that neglect dyslexia assessment after stroke should include text materials comparable to those read in everyday life. Increasing the spatial extent of training materials in future research might also yield better functional generalization after right brain stroke.

Effects of language proficiency and language of the environment on aphasia therapy in a multilingual.

We examined the relative proficiency of four languages (Spanish, German, French, English) of a multilingual speaker with aphasia, JM. JM's self-rated proficiency was consistent with his naming accuracy for nouns and verbs (The Object and Action Naming Battery, Druks & Masterson, 2000) and with his performance on selected subtests of the Bilingual Aphasia Test (Paradis & Libben, 1987). Within and between-language changes were measured following two periods of language treatment, one in a highly-proficient language (Spanish) and one in a less-proficient language (English). The various outcome measures differed in their sensitivity to treatment-associated changes. Cross-language treatment effects were linked to the language of the environment at the time of testing and to relative language proficiency.

The development of stimulus-specific auditory responses requires song exposure in male but not female zebra finches.

Juvenile male zebra finches develop their song by imitation. Females do not sing but are attracted to males' songs. With functional magnetic resonance imaging and event-related potentials we tested how early auditory experience shapes responses in the auditory forebrain of the adult bird. Adult male birds kept in isolation over the sensitive period for song learning showed no consistency in auditory responses to conspecific songs, calls, and syllables. Thirty seconds of song playback each day over development, which is sufficient to induce song imitation, was also sufficient to shape stimulus-specific responses. Strikingly, adult females kept in isolation over development showed responses similar to those of males that were exposed to songs. We suggest that early auditory experience with songs may be required to tune perception toward conspecific songs in males, whereas in females song selectivity develops even without prior exposure to song.

Functional MRI of the zebra finch brain during song stimulation suggests a lateralized response topography.

Electrophysiological and activity-dependent gene expression studies of birdsong have contributed to the understanding of the neural representation of natural sounds. However, we have limited knowledge about the overall spatial topography of song representation in the avian brain. Here, we adapt the noninvasive functional MRI method in mildly sedated zebra finches (Taeniopygia guttata) to localize and characterize song driven brain activation. Based on the blood oxygenation level-dependent signal, we observed a differential topographic responsiveness to playback of bird's own song, tutor song, conspecific song, and a pure tone as a nonsong stimulus. The bird's own song caused a stronger response than the tutor song or tone in higher auditory areas. This effect was more pronounced in the medial parts of the forebrain. We found left-right hemispheric asymmetry in sensory responses to songs, with significant discrimination between stimuli observed only in the right hemisphere. This finding suggests that perceptual responses might be lateralized in zebra finches. In addition to establishing the feasibility of functional MRI in sedated songbirds, our results demonstrate spatial coding of song in the zebra finch forebrain, based on developmental familiarity and experience.