Blog Archives

The effect of language cues on infants’ representational flexibility in a deferred imitation task

Twelve- and 15-month-old infants who received simple verbal cues at encoding and retrieval exhibited superior representational flexibility on an imitation task compared to infants who did not receive those cues. Verbal cues can help early-verbal infants overcome perceptual dissimilarity and express knowledge in novel situations.

from Infant Behavior and Development

Auditory N1 as a change-related automatic response

These results support the idea that On-N1 is a change-related component elicited by a sound pressure change.

from Neuroscience Research

Why tests appear to prevent forgetting: A distribution-based bifurcation model

Retrieving information from memory produces more learning than does being presented with the same information, and the benefits of such retrieval appear to grow as the delay before a final recall test grows longer. Recall tests, however, measure the number of items that are above a recall threshold, not memory strength per se. According to the model proposed in this paper, tests without feedback produce bifurcated item distributions: Retrieved items become stronger, but non-retrieved items remain weak, resulting in a gap between the two classes of items. Restudying items, on the other hand, strengthens all items, though to a lesser degree than does retrieval. These differing outcomes can make tested items appear to be forgotten more slowly than are restudied items—even if all items are forgotten at the same rate—because the test-induced bifurcation leaves items either well above or well below threshold. We review prior evidence and present three new experiments designed to test the bifurcation interpretation.

from the Journal of Memory and Language

Demographically corrected norms for African Americans and Caucasians on the Hopkins Verbal Learning Test-Revised, Brief Visuospatial Memory Test-Revised, Stroop Color and Word Test, and Wisconsin Card Sorting Test 64-Card Version

Memory and executive functioning are two important components of clinical neuropsychological (NP) practice and research. Multiple demographic factors are known to affect performance differentially on most NP tests, but adequate normative corrections, inclusive of race/ethnicity, are not available for many widely used instruments. This study compared demographic contributions for widely used tests of verbal and visual learning and memory (Brief Visual Memory Test-Revised, Hopkins Verbal Memory Test-Revised) and executive functioning (Stroop Color and Word Test, Wisconsin Card Sorting Test-64) in groups of healthy Caucasians (n = 143) and African Americans (n = 103). Demographic factors of age, education, gender, and race/ethnicity were found to be significant factors on some indices of all four tests. The magnitude of demographic contributions (especially age) was greater for African Americans than for Caucasians on most measures. New, demographically corrected T-score formulas were calculated for each race/ethnicity. The rates of NP impairment using previously published normative standards significantly overestimated NP impairment in African Americans. Utilizing the new demographic corrections developed and presented herein, NP impairment rates were comparable between the two race/ethnicities and were unrelated to the other demographic characteristics (age, education, gender) in either race/ethnicity group. Findings support the need to consider extended demographic contributions to neuropsychological test performance in clinical and research settings.

from the Journal of Clinical and Experimental Neuropsychology

Effects of Automatic/Controlled Access Processes on Semantic Memory in Alzheimer’s Disease

This study examines the impact of automatic/controlled access processes on the semantic network in 30 patients with Alzheimer’s disease (AD). The AD group was compared with a control group using a battery of neuropsychological tests, a variation of Hodges’s semantic testing battery, designed to assess semantic knowledge. The AD group had markedly lower scores than the normal group on each semantic test, but with a different degree of deterioration depending on the nature of the processes (controlled/automatic) in accessing the semantic network. AD patients had poorer performances on the explicit semantic tasks mainly involving controlled-process access (e.g., the WAIS Similarities Subtest) than those involving mainly automatic-process access (e.g., the Verbal Automatism test). Analyses of confidence intervals allowed a gradient of impaired performances in increasing order to be elaborated: a) the Verbal Automatism test, b) the WAIS Vocabulary Subtest, c) the WAIS Information Subtest, d) the Letter Fluency Task, e) Naming as a Response to Definition, f) the Category Fluency Task, g) the WAIS Similarities Subtest, and h) the Oral Denomination 80 Test. The results of our study suggest that explicit semantic tasks needing passive or automatic processes to access semantic memory would be better preserved in AD.

from the Journal of Alzheimer’s Disease

Diffusion tensor imaging of the hippocampus and verbal memory performance: The RUN DMC Study

Conclusion: Microstructural integrity of the hippocampus assessed by DTI is related to verbal memory performance in elderly with SVD, also in participants with an intact appearing hippocampus. Changes in hippocampal microstructure may be an early marker of underlying neurodegenerative disease, before macrostructural (i.e., volumetric) changes occur.

from Human Brain Mapping

Executive and Memory Function in Adolescents Born Very Preterm

CONCLUSIONS Even after exclusion of preterm subjects with significant disabilities, adolescents born preterm in the early 1990s were at increased risk of deficits in executive function and memory.

from Pediatrics

Spatial Selective Auditory Attention in the Presence of Reverberant Energy: Individual Differences in Normal-Hearing Listeners

Listeners can selectively attend to a desired target by directing attention to known target source features, such as location or pitch. Reverberation, however, reduces the reliability of the cues that allow a target source to be segregated and selected from a sound mixture. Given this, it is likely that reverberant energy interferes with selective auditory attention. Anecdotal reports suggest that the ability to focus spatial auditory attention degrades even with early aging, yet there is little evidence that middle-aged listeners have behavioral deficits on tasks requiring selective auditory attention. The current study was designed to look for individual differences in selective attention ability and to see if any such differences correlate with age. Normal-hearing adults, ranging in age from 18 to 55 years, were asked to report a stream of digits located directly ahead in a simulated rectangular room. Simultaneous, competing masker digit streams were simulated at locations 15° left and right of center. The level of reverberation was varied to alter task difficulty by interfering with localization cues (increasing localization blur). Overall, performance was best in the anechoic condition and worst in the high-reverberation condition. Listeners nearly always reported a digit from one of the three competing streams, showing that reverberation did not render the digits unintelligible. Importantly, inter-subject differences were extremely large. These differences, however, were not significantly correlated with age, memory span, or hearing status. These results show that listeners with audiometrically normal pure tone thresholds differ in their ability to selectively attend to a desired source, a task important in everyday communication. Further work is necessary to determine if these differences arise from differences in peripheral auditory function or in more central function.

from JARO — Journal of the Association for Research in Otolaryngology

Phonological awareness and writing skills in children with Down syndrome*

BACKGROUND: Down syndrome, phonological awareness, writing and working memory.
AIM: to evaluate the phonological awareness of Brazilian children with Down syndrome; to analyze the relationship between the writing hypothesis and the phonological awareness scores of the participants; to compare the performance of children with Down syndrome to that of children with typical development according to the Phonological Awareness: Tool for sequential evaluation (PHONATSE), using the writing hypothesis as a matching criteria; to verify the correlation between the phonological awareness measurements and the phonological working memory.
METHOD: a group of eleven children aged between 7 and 14 years (average: 9y10m) was selected for the study. Phonological awareness was evaluated using the PHONATSE. The phonological working memory was evaluated through an instrument developed by the researcher.
RESULTS: all subjects presented measurable levels of phonological awareness through the PHONATSE. The phonological awareness scores and the writing hypothesis presented a significant positive association. The performance of children with Down syndrome was significantly lower than children with typical development who presented the same writing hypothesis. Measurements of phonological awareness and phonological working memory presented significant positive correlations.
CONCLUSION: the phonological awareness of Brazilian children with Down syndrome can be evaluated through the PHONATSE. Syllable awareness improves with literacy, whereas phonemic awareness seems to result from written language learning. The phonological working memory influences the performance of children with Down syndrome in phonological awareness tasks.

from Pró-Fono Revista de Atualização Científica

Developmental Trajectories From Birth to School Age in Healthy Term-Born Children

In healthy children the stability of motor development from birth until school age is low. Maternal socioeconomic status and verbal intelligence rather than the infants’ scores on early motor tests signified added value for complex cognitive functions at school age

from Pediatrics

The Association Between Developmental Coordination Disorder and Other Developmental Traits

Children with probable DCD had an increased risk of difficulties in attention, social skills, reading, and spelling. These additional difficulties need to be screened for during assessment and considered when formulating interventions.

from Pediatrics

Behavioral semantics of learning and crossmodal processing in auditory cortex: The semantic processor concept

Two phenomena of auditory cortex activity have recently attracted attention, namely that the primary field can show different types of learning-related changes of sound representation and that during learning even this early auditory cortex is under strong multimodal influence. Based on neuronal recordings in animal auditory cortex during instrumental tasks, in this review we put forward the hypothesis that these two phenomena serve to derive the task-specific meaning of sounds by associative learning. To understand the implications of this tenet, it is helpful to realize how a behavioral meaning is usually derived for novel environmental sounds. For this purpose, associations with other sensory, e.g. visual, information are mandatory to develop a connection between a sound and its behaviorally relevant cause and/or the context of sound occurrence. This makes it plausible that in instrumental tasks various non-auditory sensory and procedural contingencies of sound generation become co-represented by neuronal firing in auditory cortex. Information related to reward or to avoidance of discomfort during task learning, that is essentially non-auditory, is also co-represented. The reinforcement influence points to the dopaminergic internal reward system, the local role of which for memory consolidation in auditory cortex is well-established. Thus, during a trial of task performance, the neuronal responses to the sounds are embedded in a sequence of representations of such non-auditory information. The embedded auditory responses show task-related modulations of auditory responses falling into types that correspond to three basic logical classifications that may be performed with a perceptual item, i.e. from simple detection to discrimination, and categorization. This hierarchy of classifications determine the semantic “same-different” relationships among sounds. Different cognitive classifications appear to be a consequence of the design of a learning task and lead to a recruitment of different excitatory and inhibitory mechanisms and to distinct spatiotemporal metrics of map activation to represent a sound.

from Hearing Research

Improvement in verbal memory after withdrawal of carbamazepine and valproate in patients with well-controlled epilepsy: a randomized, double-blind study

Conclusions – Withdrawal was randomized to placebo, but the choice of medication was not randomized to placebo. This means that the shown differences in neuropsychological outcome cannot with full certainty be attributed to either antiepileptic drug. The improvement of memory, after both carbamazepine and valproate withdrawal, was slight, and the impact on daily life function is uncertain.

from Acta Neurologica Scandinavica

Comparison of verbal memory impairment rates in mild cognitive impairment

There are no accepted guidelines establishing the most sensitive neuropsychological methods to define memory impairment in mild cognitive impairment (MCI). We investigated whether similar impairment rates were observed between the Hopkins Verbal Learning Test-Revised (HVLT-R) and Logical Memory (LM) in 90 patients with amnestic or amnestic plus MCI. On HVLT-R delayed recall, 80% of participants performed in the MCI range compared to only 32.2% on LM II. The same pattern was seen for both amnestic and amnestic plus subtypes. Individuals impaired on HVLT-R delayed recall performed significantly worse on LM first recall and on delayed recall of LM Story A than those not impaired. MCI patients with executive dysfunction performed significantly worse than patients with no executive impairment on both LM I and HVLT-R Total Learning, but not for delayed recall of either measure. Future studies can address the longitudinal course of impairment on these measures.

from the Journal of Clinical and Experimental Neuropsychology

Verbal memory impairment in severe closed head injury: The role of encoding and consolidation

We applied the item-specific deficit approach (ISDA) to California Verbal Learning Test data obtained from 56 severe, acceleration-deceleration closed head injury (CHI) participants and 62 controls. The CHI group demonstrated deficits on all ISDA indices in comparison to controls. Regression analyses indicated that encoding deficits, followed by consolidation deficits, accounted for most of the variance in delayed recall. Additionally, level of acquisition played a partial role in CHI-associated consolidation difficulties. Finally, CHI encoding deficits were largely driven by low semantic clustering during list learning. These results suggest that encoding (primary) and consolidation (secondary) deficits account for CHI-associated verbal memory impairment.

from the Journal of Clinical and Experimental Neuropsychology