Cognitive Neuropsychology最新文献

Individuals with conduction aphasia (CA), associated with post-lexical impairments, frequently produce phonological substitution errors. This study examined whether such substitutions reflect phonological simplification principles (e.g., preference for unmarked phonemes, sonority-based tendencies, assimilation) or are mainly constrained by phonological similarity. Under a similarity account, substitutions should preserve key phonological features of the target, even when the result is more complex. We analysed 339 consonant and 98 vowel substitution errors produced by 14 individuals with CA across naming, reading, and repetition tasks, and compared them with errors from one individual with apraxia of speech (AOS) without aphasia. CA errors were strongly guided by phonological similarity, with most substitutions differing from the target by only one or two features. Although these errors did not violate phonological principles, they often maintained salient target features even when producing more complex sounds. In contrast, the AOS participant showed a tendency toward simpler, unmarked phonemes. These findings indicate distinct underlying mechanisms in CA and AOS and highlight feature-level preservation in CA phonological encoding.

Response delays in language tasks yield variable results in people with aphasia (PWA): some improve, some worsen, and others have no significant change in accuracy relative to immediate response conditions. Current models cannot account for different performance patterns between delayed naming and repetition tasks within the same individual.One key way that naming differs from repetition is the duration of stimulus exposure. We investigated the contribution of stimulus duration to temporal processing variability in aphasia. 19 PWA completed tests of immediate and delayed naming and repetition. Pictures in short-exposure naming appeared for only 100 ms, whereas pictures in the long exposure condition appeared for3000 ms. While this manipulation did not eliminate diverging performance accuracy between delayed naming and repetition, shortening picture duration did increase task difficulty and revealed greater variability in temporal processing. We discuss the role of visual semantic activation in the time course of word retrieval.

Visual information reaches the cortex via multiple pathways, most notably the magnocellular (M) and parvocellular (P) streams. How their inputs are integrated remains unclear. We previously documented the case of Davida, a young woman who perceives high-contrast, sharply bounded 2D shapes as rotated or mirror-reversed, while he perception normalizes when stimuli are blurred, low in contrast, or brief. Here, we first review previous findings and propose that her disorder may reflect abnormally strong P-on-M inhibition. We then present three studies supporting this account: two demonstrate abnormally strong P-on-M inhibition in Davida, and a third shows that the degree of P-M imbalance predicts mirror-image discrimination difficulty in neurotypical individuals. Finally, re-analysis of published data suggests that distinct aspects of shape orientation are differentially sensitive to P-M imbalance. Together, these findings highlight the crucial role of dynamic P-M interactions in shaping visual perception.

ABSTRACTThis cross-linguistic study examined inflectional morphology and word order in Moroccan Arabic (MA) and English-speaking persons with agrammatic aphasia (PWAA). MA has rich verbal morphology and flexible word order, whereas English has limited morphology and rigid order, providing a strong test of accounts of agrammatism. The closed-class deficit hypothesis predicts selective impairment of inflections with preserved word order, while the syntactic deficit hypothesis (SDH) attributes the disorder to a syntactic impairment affecting both domains. Speech from nine MA speakers (four PWAA, five typical participants (TP)) and ten English speakers (five PWAA, five TP) was analyzed. In both languages, PWAA showed deficits in morphology and word order, supporting the SDH. Severity patterns differed: MA-speaking PWAA trended toward greater morphological impairment, whereas English-speaking PWAA showed greater word order disruption. MA-speaking PWAA also deviated from TP's canonical VSO pattern, suggesting compensatory subject-initial strategies. Findings support a core syntactic deficit modulated by language typology.

Previous research showed that people enumerate objects faster and more accurately when they form clusters, a phenomenon called "groupitizing". While mainly studied visually, its dependence on vision is unclear. Congenitally blind (CB) individuals provide a critical test: if vision is essential, CB people should lack groupitizing; if not, they may apply it across modalities, potentially outperforming sighted participants. We compared CB and sighted adults on an auditory groupitizing task, based on the estimation of 5-12 pure tones presented either randomly or grouped by temporal proximity. Both groups showed lower errors and higher precision for grouped sequences, confirming that groupitizing can emerge without visual experience. Importantly, for larger numerosities, sighted individuals' grouping benefit decreased, whereas CB participants maintained robust advantages across all set sizes. These findings suggest that groupitizing relies on amodal perceptual mechanisms and that congenital blindness may enhance auditory enumeration strategies.

This study investigates cross-linguistic asymmetries in noun and verb production in a Hindi-English bilingual with Broca's aphasia (RZ), focusing on the influence of task demands (narrative vs. noun naming, verb naming, repetition), morphological richness, and code-switching (frequency and type). RZ exhibited features of agrammatism in both languages, with more pronounced deficits in English. RZ showed grammatical class asymmetries in noun-verb production across tasks. He produced more verbs than nouns in Hindi in the narrative task, likely due to its rich morphology, while showing comparable noun-verb production in naming. Verb retrieval remained consistently impaired in English across tasks. RZ frequently but rigidly code-switched, mainly inserting English nouns within Hindi matrix structure and used bilingual compound verbs, suggesting a strategy to compensate for lexical deficits in Hindi and morphosyntactic challenges in English. These findings underscore the importance of language typology and task demands in shaping aphasic symptomatology in bilinguals.

Hemianopic patients with visual field defects due to cerebral damage sometimes demonstrate residual visual capacities in their contralesional field, known as blindsight. Its associated subjective experience remains poorly understood. We developed a novel task for patients combining forced-choice detection and discrimination paradigms with a confidence scale to assess individual objective sensitivity and metacognitive sensitivity and efficiency, addressing the unique challenges of probing subjective experience in hemianopia, where visual nature is rarely evident. Four patients participated, revealing distinct perceptual and metacognitive profiles. One patient exhibited remarkable contralesional objective capacities and some preserved metacognition despite rarely reporting visual perception, suggesting subjective content may not reflect the stimulus itself. Concomitantly, preliminary results reveal ipsilesional metacognitive impairments in three patients despite optimal objective performance. Overall, we present the first application of state-of-the-art metacognitive measures to hemianopia, bridging perceptual and metacognitive measures to explore subjective experience, offering new insights into blindsight and the dissociation between consciousness and metacognitive processes.

The cognitive underpinnings of stuttering are likely heterogeneous. Yet existing research typically focuses on testing only one or a few hypotheses and on group-level differences. Here, 12 adults who stutter (AWS) completed a comprehensive battery assessing linguistic, auditory, somatosensory, rhythmic and motor abilities supporting fluent speech. Each AWS's performance was compared with that of 20 control participants to establish individual cognitive profiles. The AWS showed heterogeneous profiles; however, all exhibited some form of orosensory tactile weakness, which, for some, was the only weakness observed. These findings demonstrate the value of individualized cognitive profiling in stuttering and suggest a stronger link between stuttering and orosensory tactile processing than previously recognized.

This study investigates the predictive role of fine motor skills (FMS) and executive functions (EFs) in adult handwriting. While the initial stages of handwriting acquisition are assumed to rely upon executive functions and fine motor skills, the two components are no longer viewed as needed in automatized, expert handwriting. Thirty-three adults were assessed on dexterity, manual praxis, working memory, inhibition and flexibility to predict handwriting speed, legibility and fluency. The results showed that FMS significantly contributed to all aspects of handwriting performance, while flexibility predicted writing speed. These findings highlight that, even at a high level of expertise and automatization, handwriting remains a skill whose performance depends on executive and fine motor control capacities. They support a predictive coding model where internal models guide movement execution and monitoring. The study questions how motor and executive impairments may disrupt handwriting performance, highlighting the need for further research into this complex motor behaviour.

This study explores bimodal cross-language interactions in the context of sign language vocabulary learning. Specifically, whether such interactions occur during oral language production, and whether they extend to an oral language not directly used in the training. Across three sessions, hearing Catalan-Spanish non-signers were trained on Catalan Sign Language (LSC) signs through an associative learning task (LSC-written Catalan). Participants subsequently performed an LSC-to-Catalan prime translation task with primes written in Catalan or Spanish. The primes were either phonologically related or unrelated to the target signs via their LSC translations. Behaviourally, LSC phonologically related word primes elicited faster translations, regardless of the prime language. Conversely, the N400 ERP component showed prime language-dependent effects. N400 differences were initially limited to Catalan, the training language, and extended to Spanish by the third session. These findings highlight the dynamic interplay between oral and sign languages during early sign language learning.