One the most fundamental aspects of the human motor system is the hemispheric asymmetry seen in b... more One the most fundamental aspects of the human motor system is the hemispheric asymmetry seen in behavioral specialization. Hemispheric dominance can be inferred by a contralateral hand preference in grasping. Few studies have considered grasp orientation in the context of manual lateralization and none has looked at grasp orientation with natural prehension. Thirty right-handed adults performed precision grasps of a cylinder using the thumb and index fingers, and the opposition axis (OA) was defined as the line connecting these two contact points on the cylinder. Subjects made ten consecutive grasps with one hand (primary hand movements) followed by ten grasps with the other hand (trailing movements). Differences between primary and trailing grasps revealed that each hemisphere is capable of programming the orientation of the OA and that primary movements with the right hand significantly influenced OA orientation of the trailing left hand. These results extend the hemispheric domin...
Blind individuals have been shown on multiple occasions to compensate for their loss of sight by ... more Blind individuals have been shown on multiple occasions to compensate for their loss of sight by developing exceptional abilities in their remaining senses. While most research has been focused on perceptual abilities per se in the auditory and tactile modalities, recent work has also investigated higher-order processes involving memory and language functions. Here we examined tactile working memory for Braille in two groups of visually challenged individuals (completely blind subjects, CBS; blind with residual vision, BRV). In a first experimental procedure both groups were given a Braille tactile memory span task with and without articulatory suppression, while the BRV and a sighted group performed a visual version of the task. It was shown that the Braille tactile working memory (BrWM) of CBS individuals under articulatory suppression is as efficient as that of sighted individuals' visual working memory in the same condition. Moreover, the results suggest that BrWM may be more robust in the CBS than in the BRV subjects, thus pointing to the potential role of visual experience in shaping tactile working memory. A second experiment designed to assess the nature (spatial vs. verbal) of this working memory was then carried out with two new CBS and BRV groups having to perform the Braille task concurrently with a mental arithmetic task or a mental displacement of blocks task. We show that the disruption of memory was greatest when concurrently carrying out the mental displacement of blocks, indicating that the Braille tactile subsystem of working memory is likely spatial in nature in CBS. The results also point to the multimodal nature of working memory and show how experience can shape the development of its subcomponents.
Subcortical lesions have been simultaneously implicated in both real and simulated movement de¢ci... more Subcortical lesions have been simultaneously implicated in both real and simulated movement de¢cits. However, the analysis of the simulated opposition axis in precision grasping reveals that, in individuals with idiopathic bilateral Parkinson's disease motor imagery is impaired and that execution of overt movements is spared. This constitutes the ¢rst lesion observation congruent with the anatomical and functional dichotomy between real and simulated movements seen in experimental studies. These results underline the modality-speci¢c nature of motor imagery and show that subcortical damage di¡erentially impacts on motor activity. NeuroRe-port15:000^000
A linguistic analysis in low-risk preterm (PT) children was conducted to determine whether the ac... more A linguistic analysis in low-risk preterm (PT) children was conducted to determine whether the acquisition of complex aspects of the lexicon, such as verbs, was in¯uenced by their premature birth status and whether sociocultural factors played a modulating role in this aspect of cognitive development. Fifty-one PT children, distributed in three birthweight groups Ð extremely low (780±1200 g), very low (1201±1500 g) and low (1501±2210 g) Ð were evaluated at 42 months and 60 months of age to assess their production of main, auxiliary and non-®nite verb types and tokens relative to that of two control groups of fullterm children matched for age and socioeconomic level. The children's verb lexicon was collected during a 20-min controlled play context. Analyses of transcript data revealed ®rst that the eect of sociocultural variables was independent of birth status or age. Further analyses revealed signi®cant dierences, indicating a marked increase in both verb type and token usage in the control children, whereas verb production in the three groups of PT children remained generally poorer. The data suggest that impaired language development is a cognitive consequence of prematurity independently of birthweight.
One of the frequent signs of Parkinson's disease (PD) is the presence of a progressive hypokineti... more One of the frequent signs of Parkinson's disease (PD) is the presence of a progressive hypokinetic dysarthria. Numerous studies have since documented speech motor impairment, but attempts at quantifying any such changes longitudinally throughout the early course of the disease have been rare. In this study, a retrospective analysis of speech was conducted on two well-known individuals with PD and two matched controls to determine if certain acoustic measures were sensitive markers of early pathophysiologic changes or treatment response in PD. Acoustic analyses were conducted on samples of speech produced over a 10-year period surrounding the time of disease diagnosis. Analyses revealed that, for both PD cases, a decrease in fundamental frequency (F 0) variability during free speech was detected prior to clinical diagnosis. Changes in F 0 variability and voice onset time (VOT) were also detected upon the initiation of symptomatic treatment. In a second experiment, an acoustical analysis of speech production was conducted on four newly diagnosed persons with PD and four matched controls, using a standard speech examination protocol. The objective of this follow-up study was to provide corroborating evidence for the results of the first experiment. Analyses revealed that F 0 variability during picture description was diminished in the participants with PD relative to their matched controls. In addition, pause duration was greater in participants
Objective: Although new atypical antipsychotic agents have been found to improve overall cognitiv... more Objective: Although new atypical antipsychotic agents have been found to improve overall cognitive function in patients with schizophrenia (SZ), some aspects of memory, attention and executive functions still remain impaired. Acetylcholinesterase (AChE) inhibitors, such as rivastigmine, have been shown to improve cognition in other disorders, particularly Alzheimer's disease. Dysfunctions in cholinergic systems, especially in the prefrontal cortex, have been identified in SZ, suggesting that cholinesterase inhibitors may be effective in treating cognitive deficits in this disease. Research design and methods: Using a randomized crossover design, we assessed SZ patients with stable symptoms and poor cognitive functioning. Fifty-eight patients with memory deficits, according to subjective complaints or based on clinicians' observations, were assessed with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and Subjective Scale to Investigate Cognition in Schizophrenia (SSTICS). Only 24 of these subjects met the inclusion criteria. Twenty patients took part in the study (four dropped out). All subjects meeting the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) criteria for SZ were maintained on their current antipsychotic medication (18 atypicals and two typicals) and were randomly assigned to treatment with rivastigmine. Dosage was a function of tolerability, beginning at 3 mg/day and progressively increasing to 9 mg/day. Subjects were given the Cambridge Neuropsychological Test Automated Battery (CANTAB) at baseline and 3 and 6 months. Results: The results revealed no significant improvement in any of the cognitive variables investigated following rivastigmine treatment and symptom severity scores remained unchanged over all recorded time periods. Conclusion: Rivastigmine treatment did not appear to enhance cognition in SZ patients with important cognitive impairments. This finding needs to be interpreted with care and requires substantiation with larger sample size studies with patients treated with cognitive enhancer for longer periods.
In this study, we examined the influence of child gender and sociocultural (SCL) factors in langu... more In this study, we examined the influence of child gender and sociocultural (SCL) factors in language production. Subjects were French Parisian children in nine age groups (24, 27, 30, 33, 36, 39, 42, 45 and 48 months). A total of 316 language samples were recorded during a 20-min standardized play session. Measures of grammatical and lexical development included Mean Length of Utterance (MLU) and word type and token-specifically, grammatical words such as determiners, prepositions and pronouns as well as verbs. ANOVAs revealed strong influences of SCL, with children from high SCL families showing more complex lexical productions and a higher rate of development. These observations suggest that amount of exposure to language accounts for this differential rate of acquisition. Analyses also revealed a general effect of gender, showing a small advantage in language production for girls over boys until 36 months of age.
Consonant production following the sensory restoration of audition was investigated in 22 preling... more Consonant production following the sensory restoration of audition was investigated in 22 prelinguistically deaf French children who received cochlear implants. Spontaneous speech productions were recorded at 6, 12, and 18 months post-surgery and consonant inventories were derived from both glossable and non-glossable phones using two acquisition criteria. The results showed that children initiated appropriate production of consonants after six months of implant use. Stops and labials were the most frequently produced speech sounds, whereas glides and palatals were still infrequent after 18 months. Speech accuracy also improved throughout the study. Consonant visibility appeared to influence the order of acquisition in the first months following the implantation and, as experience with auditory information increased, patterns of development tended to resemble those seen in children with normal hearing. Finally, a signed mode of communication and oral rehabilitation programs prior to implantation were better outcome predictors than age at implantation.
In the study of language acquisition following early brain damage, results have been divergent. O... more In the study of language acquisition following early brain damage, results have been divergent. On one hand, some studies claim that language eventually resumes to normal, whereas, on the other hand, studies show lasting deficits throughout development. Discrepancies in the results could arise from different etiologies and tests used. This study attempts to determine the extent to which the development of verb production is affected in later development in children who had simple partial epilepsy (SPE). Measures of diversity and fluency of three verb types, namely main verbs, auxiliary and copula verbs, and nonfinite verbs were used on three children diagnosed as SPE and compared to control groups. Our main results show a limited production of auxiliary verbs. Further analysis of their productions suggest a telegraphic style of speech, as reflected by a superior production of nonfinite verb type compared with normal children. These findings are interpreted as reflecting long-lasting consequences of early brain damage with respect to language development.
The productivity of lexical categories was studied longitudinally in a sample of 17 young hearing... more The productivity of lexical categories was studied longitudinally in a sample of 17 young hearing-impaired French-speaking children with cochlear implants. Age of implantation ranged from 22 months to 76 months. Spontaneous speech samples were collected at six-month intervals over a period of 36 months, starting at the one-word stage. Four general measures of their linguistic production (number of utterances, verbal fluency, vocabulary, and grammatical production) as well as 36 specific lexical categories, according to the CHILDES codes, were computed in terms of tokens, i.e., total number of words. Cochlear-implanted children (CI) were compared to a French database of normally hearing children aged 2-4 compiled by the first author. Follow-up results indicate that, at the two-year post-implantation follow-up, noun, and verb morphology was significantly impaired. At the three-year followup, the cochlear-implanted group had recovered on adjectives, determiners and nouns, main verbs, and auxiliaries. The two groups differed significantly in processing locative adverbs, prepositions, pronouns, and verbs (infinitive verb, modal, and modal lexical), but individual variability within the cochlear-implanted group was substantial. Results are discussed in terms of recovery and developmental trends and variability in the acquisition of lexical categories by French children two years and three years post-implantation.
The neuropsychological literature on the processing of emotions in Parkinson's disease (PD) revea... more The neuropsychological literature on the processing of emotions in Parkinson's disease (PD) reveals conflicting evidence about the role of the basal ganglia in the recognition of facial emotions. Hence, the present study had two objectives. One was to determine the extent to which the visual processing of emotions and objects differs in PD. The other was to assess the impact of cognitive load on the processing of these types of information. Thirty-one patients with idiopathic PD (IPD) under dopamine replacement therapy (DRT) were compared to 30 control subjects on emotion and object recognition tasks. Recognition of objects was more accurate and faster than recognition of facial expressions of emotion, for both groups of subjects. In a second experiment using an N-back procedure with the same stimuli-a more demanding task with a higher cognitive load-patients with IPD were as accurate as control subjects in detecting the correct sequential presentation of stimuli, but were much slower in their decision responses. This indicates that IPD patients under DRT are not impaired in encoding emotion or object information, but that they have difficulty with the processing demands of the N-back task. Thus, patients with IPD appear to be more sensitive to cognitive load than to type of information, whether facial emotions or objects. In this perspective, one must consider that a deafferented dopaminergic system has problems processing more complex information before one can posit the existence of deficits affecting a specific type of information.
Prehension movements of the right hand were recorded in a right-handed man (AC), with an injury t... more Prehension movements of the right hand were recorded in a right-handed man (AC), with an injury to the left posterior parietal cortex (PPC) and with a section of the left half of the splenium. The kinematic analysis of AC's grasping movements in direct and perturbed conditions was compared to that of Wve control subjects. A novel eVect in prehension was revealed-a hemispace eVect-in healthy controls only. Movements to the left hemispace were faster, longer, and with a smaller grasp aperture; perturbation of both object position and distance resulted in the attenuation of the direction eVect on movement time and the time to velocity peak, with a reverse pattern in the time to maximum grip aperture. Nevertheless, the correlation between transport velocity amplitude and grasp aperture remained stable in both perturbed and non-perturbed movements, reXecting the coordination between reaching and grasping in control subjects. In contrast, transport and grasp, as well as their coordination in both direct and perturbed conditions, were negatively aVected by the PPC and splenium lesion in AC, suggesting that transport and grasp rely on two functionally identiWable subsystems.
The SOC framework does not take into account the fact that the oral modality consists of purely t... more The SOC framework does not take into account the fact that the oral modality consists of purely transient data, which is not the case for the other modalities. This, however, has important consequences on the nature of oral and written language, on language consciousness, on child language development, and on the history of linguistics.
This research was supported, in part, by scholarships from the National Sciences and Engineering ... more This research was supported, in part, by scholarships from the National Sciences and Engineering Council of Canada, the Fonds québécois de la recherche sur la nature et les technologies, and grants from the Social Sciences and Humanities Research Council. We thank Jenny Staab, Sara Bélanger, and Valérie Bédirian for helping with data collection and François Labelle for drawing the pictures. We also thank Patrick Bonin and an anonymous reviewer for their comments on an earlier version of this article. Correspondence concerning this article should be addressed to H. Cohen,
The role of the frontal lobe in cross-modal visual-auditory processing has been documented in exp... more The role of the frontal lobe in cross-modal visual-auditory processing has been documented in experiments using incongruent/ congruent paradigms. In this study, 4 patients with left frontal World Health Organization Grade II glioma were assessed during pre-, intra-, and postoperative sessions with picture-naming and verbal-visual task requiring judgment of congruence between pictures and words. During awake brain surgery, the naming and crossmodal tasks were coupled with electrical stimulation inactivating restricted specific regions. For all patients, focal brain stimulation in the dorsolateral prefrontal cortex elicited picture-word matching disturbances but no naming impairment, and the elicited errors exclusively appeared in incongruent and not congruent conditions. The dissociation observed between correct picture naming and disturbed cross-modal judgment shows that electrical stimulation of a discrete cortical area within the left dorsolateral prefrontal cortex can inhibit the simultaneous processing of visual-verbal information without disturbing larger networks involved in the naming process.
The discussion of whether emotions are categorical in nature has loomed large ever since Darwin (... more The discussion of whether emotions are categorical in nature has loomed large ever since Darwin (1872) posited an evolutionary base for human emotion expressions. This discussion has traditionally conflated two issues. First, is emotion elicitation categorical, such that different emotions are associated with qualitatively different neural substrates, expressive reactions, action tendencies, and feeling states resulting in discrete emotional states? And second, is the perception of emotion expressions categorical, resulting in the use of discrete emotion labels? These questions have been traditionally conflated because research on the universal use of emotion labels for facial expressions became a cornerstone for the assumption of discrete emotions. In this chapter I present an overview of this discussion that concludes a middle stance in which some processes are dimensional and others categorical. Importantly, from a functional perspective the use of emotion categories by perceiver...
Changes in speech and voice are characteristic of both neurodegenerative and psychiatric disorder... more Changes in speech and voice are characteristic of both neurodegenerative and psychiatric disorders. The acoustic analysis of speech production of several common disorders related to central nervous system dysfunction is summarized here. A brief introduction to the neurobiology of speech production illustrates how the cerebral structures and neurotransmitters involved in neurologic (e.g., Parkinson disease) and psychiatric (e.g., depression) disturbances contribute to specific speech alterations. A succinct overview of voice recording and data processing equipment is also provided.
One the most fundamental aspects of the human motor system is the hemispheric asymmetry seen in b... more One the most fundamental aspects of the human motor system is the hemispheric asymmetry seen in behavioral specialization. Hemispheric dominance can be inferred by a contralateral hand preference in grasping. Few studies have considered grasp orientation in the context of manual lateralization and none has looked at grasp orientation with natural prehension. Thirty right-handed adults performed precision grasps of a cylinder using the thumb and index fingers, and the opposition axis (OA) was defined as the line connecting these two contact points on the cylinder. Subjects made ten consecutive grasps with one hand (primary hand movements) followed by ten grasps with the other hand (trailing movements). Differences between primary and trailing grasps revealed that each hemisphere is capable of programming the orientation of the OA and that primary movements with the right hand significantly influenced OA orientation of the trailing left hand. These results extend the hemispheric domin...
Blind individuals have been shown on multiple occasions to compensate for their loss of sight by ... more Blind individuals have been shown on multiple occasions to compensate for their loss of sight by developing exceptional abilities in their remaining senses. While most research has been focused on perceptual abilities per se in the auditory and tactile modalities, recent work has also investigated higher-order processes involving memory and language functions. Here we examined tactile working memory for Braille in two groups of visually challenged individuals (completely blind subjects, CBS; blind with residual vision, BRV). In a first experimental procedure both groups were given a Braille tactile memory span task with and without articulatory suppression, while the BRV and a sighted group performed a visual version of the task. It was shown that the Braille tactile working memory (BrWM) of CBS individuals under articulatory suppression is as efficient as that of sighted individuals' visual working memory in the same condition. Moreover, the results suggest that BrWM may be more robust in the CBS than in the BRV subjects, thus pointing to the potential role of visual experience in shaping tactile working memory. A second experiment designed to assess the nature (spatial vs. verbal) of this working memory was then carried out with two new CBS and BRV groups having to perform the Braille task concurrently with a mental arithmetic task or a mental displacement of blocks task. We show that the disruption of memory was greatest when concurrently carrying out the mental displacement of blocks, indicating that the Braille tactile subsystem of working memory is likely spatial in nature in CBS. The results also point to the multimodal nature of working memory and show how experience can shape the development of its subcomponents.
Subcortical lesions have been simultaneously implicated in both real and simulated movement de¢ci... more Subcortical lesions have been simultaneously implicated in both real and simulated movement de¢cits. However, the analysis of the simulated opposition axis in precision grasping reveals that, in individuals with idiopathic bilateral Parkinson's disease motor imagery is impaired and that execution of overt movements is spared. This constitutes the ¢rst lesion observation congruent with the anatomical and functional dichotomy between real and simulated movements seen in experimental studies. These results underline the modality-speci¢c nature of motor imagery and show that subcortical damage di¡erentially impacts on motor activity. NeuroRe-port15:000^000
A linguistic analysis in low-risk preterm (PT) children was conducted to determine whether the ac... more A linguistic analysis in low-risk preterm (PT) children was conducted to determine whether the acquisition of complex aspects of the lexicon, such as verbs, was in¯uenced by their premature birth status and whether sociocultural factors played a modulating role in this aspect of cognitive development. Fifty-one PT children, distributed in three birthweight groups Ð extremely low (780±1200 g), very low (1201±1500 g) and low (1501±2210 g) Ð were evaluated at 42 months and 60 months of age to assess their production of main, auxiliary and non-®nite verb types and tokens relative to that of two control groups of fullterm children matched for age and socioeconomic level. The children's verb lexicon was collected during a 20-min controlled play context. Analyses of transcript data revealed ®rst that the eect of sociocultural variables was independent of birth status or age. Further analyses revealed signi®cant dierences, indicating a marked increase in both verb type and token usage in the control children, whereas verb production in the three groups of PT children remained generally poorer. The data suggest that impaired language development is a cognitive consequence of prematurity independently of birthweight.
One of the frequent signs of Parkinson's disease (PD) is the presence of a progressive hypokineti... more One of the frequent signs of Parkinson's disease (PD) is the presence of a progressive hypokinetic dysarthria. Numerous studies have since documented speech motor impairment, but attempts at quantifying any such changes longitudinally throughout the early course of the disease have been rare. In this study, a retrospective analysis of speech was conducted on two well-known individuals with PD and two matched controls to determine if certain acoustic measures were sensitive markers of early pathophysiologic changes or treatment response in PD. Acoustic analyses were conducted on samples of speech produced over a 10-year period surrounding the time of disease diagnosis. Analyses revealed that, for both PD cases, a decrease in fundamental frequency (F 0) variability during free speech was detected prior to clinical diagnosis. Changes in F 0 variability and voice onset time (VOT) were also detected upon the initiation of symptomatic treatment. In a second experiment, an acoustical analysis of speech production was conducted on four newly diagnosed persons with PD and four matched controls, using a standard speech examination protocol. The objective of this follow-up study was to provide corroborating evidence for the results of the first experiment. Analyses revealed that F 0 variability during picture description was diminished in the participants with PD relative to their matched controls. In addition, pause duration was greater in participants
Objective: Although new atypical antipsychotic agents have been found to improve overall cognitiv... more Objective: Although new atypical antipsychotic agents have been found to improve overall cognitive function in patients with schizophrenia (SZ), some aspects of memory, attention and executive functions still remain impaired. Acetylcholinesterase (AChE) inhibitors, such as rivastigmine, have been shown to improve cognition in other disorders, particularly Alzheimer's disease. Dysfunctions in cholinergic systems, especially in the prefrontal cortex, have been identified in SZ, suggesting that cholinesterase inhibitors may be effective in treating cognitive deficits in this disease. Research design and methods: Using a randomized crossover design, we assessed SZ patients with stable symptoms and poor cognitive functioning. Fifty-eight patients with memory deficits, according to subjective complaints or based on clinicians' observations, were assessed with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and Subjective Scale to Investigate Cognition in Schizophrenia (SSTICS). Only 24 of these subjects met the inclusion criteria. Twenty patients took part in the study (four dropped out). All subjects meeting the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) criteria for SZ were maintained on their current antipsychotic medication (18 atypicals and two typicals) and were randomly assigned to treatment with rivastigmine. Dosage was a function of tolerability, beginning at 3 mg/day and progressively increasing to 9 mg/day. Subjects were given the Cambridge Neuropsychological Test Automated Battery (CANTAB) at baseline and 3 and 6 months. Results: The results revealed no significant improvement in any of the cognitive variables investigated following rivastigmine treatment and symptom severity scores remained unchanged over all recorded time periods. Conclusion: Rivastigmine treatment did not appear to enhance cognition in SZ patients with important cognitive impairments. This finding needs to be interpreted with care and requires substantiation with larger sample size studies with patients treated with cognitive enhancer for longer periods.
In this study, we examined the influence of child gender and sociocultural (SCL) factors in langu... more In this study, we examined the influence of child gender and sociocultural (SCL) factors in language production. Subjects were French Parisian children in nine age groups (24, 27, 30, 33, 36, 39, 42, 45 and 48 months). A total of 316 language samples were recorded during a 20-min standardized play session. Measures of grammatical and lexical development included Mean Length of Utterance (MLU) and word type and token-specifically, grammatical words such as determiners, prepositions and pronouns as well as verbs. ANOVAs revealed strong influences of SCL, with children from high SCL families showing more complex lexical productions and a higher rate of development. These observations suggest that amount of exposure to language accounts for this differential rate of acquisition. Analyses also revealed a general effect of gender, showing a small advantage in language production for girls over boys until 36 months of age.
Consonant production following the sensory restoration of audition was investigated in 22 preling... more Consonant production following the sensory restoration of audition was investigated in 22 prelinguistically deaf French children who received cochlear implants. Spontaneous speech productions were recorded at 6, 12, and 18 months post-surgery and consonant inventories were derived from both glossable and non-glossable phones using two acquisition criteria. The results showed that children initiated appropriate production of consonants after six months of implant use. Stops and labials were the most frequently produced speech sounds, whereas glides and palatals were still infrequent after 18 months. Speech accuracy also improved throughout the study. Consonant visibility appeared to influence the order of acquisition in the first months following the implantation and, as experience with auditory information increased, patterns of development tended to resemble those seen in children with normal hearing. Finally, a signed mode of communication and oral rehabilitation programs prior to implantation were better outcome predictors than age at implantation.
In the study of language acquisition following early brain damage, results have been divergent. O... more In the study of language acquisition following early brain damage, results have been divergent. On one hand, some studies claim that language eventually resumes to normal, whereas, on the other hand, studies show lasting deficits throughout development. Discrepancies in the results could arise from different etiologies and tests used. This study attempts to determine the extent to which the development of verb production is affected in later development in children who had simple partial epilepsy (SPE). Measures of diversity and fluency of three verb types, namely main verbs, auxiliary and copula verbs, and nonfinite verbs were used on three children diagnosed as SPE and compared to control groups. Our main results show a limited production of auxiliary verbs. Further analysis of their productions suggest a telegraphic style of speech, as reflected by a superior production of nonfinite verb type compared with normal children. These findings are interpreted as reflecting long-lasting consequences of early brain damage with respect to language development.
The productivity of lexical categories was studied longitudinally in a sample of 17 young hearing... more The productivity of lexical categories was studied longitudinally in a sample of 17 young hearing-impaired French-speaking children with cochlear implants. Age of implantation ranged from 22 months to 76 months. Spontaneous speech samples were collected at six-month intervals over a period of 36 months, starting at the one-word stage. Four general measures of their linguistic production (number of utterances, verbal fluency, vocabulary, and grammatical production) as well as 36 specific lexical categories, according to the CHILDES codes, were computed in terms of tokens, i.e., total number of words. Cochlear-implanted children (CI) were compared to a French database of normally hearing children aged 2-4 compiled by the first author. Follow-up results indicate that, at the two-year post-implantation follow-up, noun, and verb morphology was significantly impaired. At the three-year followup, the cochlear-implanted group had recovered on adjectives, determiners and nouns, main verbs, and auxiliaries. The two groups differed significantly in processing locative adverbs, prepositions, pronouns, and verbs (infinitive verb, modal, and modal lexical), but individual variability within the cochlear-implanted group was substantial. Results are discussed in terms of recovery and developmental trends and variability in the acquisition of lexical categories by French children two years and three years post-implantation.
The neuropsychological literature on the processing of emotions in Parkinson's disease (PD) revea... more The neuropsychological literature on the processing of emotions in Parkinson's disease (PD) reveals conflicting evidence about the role of the basal ganglia in the recognition of facial emotions. Hence, the present study had two objectives. One was to determine the extent to which the visual processing of emotions and objects differs in PD. The other was to assess the impact of cognitive load on the processing of these types of information. Thirty-one patients with idiopathic PD (IPD) under dopamine replacement therapy (DRT) were compared to 30 control subjects on emotion and object recognition tasks. Recognition of objects was more accurate and faster than recognition of facial expressions of emotion, for both groups of subjects. In a second experiment using an N-back procedure with the same stimuli-a more demanding task with a higher cognitive load-patients with IPD were as accurate as control subjects in detecting the correct sequential presentation of stimuli, but were much slower in their decision responses. This indicates that IPD patients under DRT are not impaired in encoding emotion or object information, but that they have difficulty with the processing demands of the N-back task. Thus, patients with IPD appear to be more sensitive to cognitive load than to type of information, whether facial emotions or objects. In this perspective, one must consider that a deafferented dopaminergic system has problems processing more complex information before one can posit the existence of deficits affecting a specific type of information.
Prehension movements of the right hand were recorded in a right-handed man (AC), with an injury t... more Prehension movements of the right hand were recorded in a right-handed man (AC), with an injury to the left posterior parietal cortex (PPC) and with a section of the left half of the splenium. The kinematic analysis of AC's grasping movements in direct and perturbed conditions was compared to that of Wve control subjects. A novel eVect in prehension was revealed-a hemispace eVect-in healthy controls only. Movements to the left hemispace were faster, longer, and with a smaller grasp aperture; perturbation of both object position and distance resulted in the attenuation of the direction eVect on movement time and the time to velocity peak, with a reverse pattern in the time to maximum grip aperture. Nevertheless, the correlation between transport velocity amplitude and grasp aperture remained stable in both perturbed and non-perturbed movements, reXecting the coordination between reaching and grasping in control subjects. In contrast, transport and grasp, as well as their coordination in both direct and perturbed conditions, were negatively aVected by the PPC and splenium lesion in AC, suggesting that transport and grasp rely on two functionally identiWable subsystems.
The SOC framework does not take into account the fact that the oral modality consists of purely t... more The SOC framework does not take into account the fact that the oral modality consists of purely transient data, which is not the case for the other modalities. This, however, has important consequences on the nature of oral and written language, on language consciousness, on child language development, and on the history of linguistics.
This research was supported, in part, by scholarships from the National Sciences and Engineering ... more This research was supported, in part, by scholarships from the National Sciences and Engineering Council of Canada, the Fonds québécois de la recherche sur la nature et les technologies, and grants from the Social Sciences and Humanities Research Council. We thank Jenny Staab, Sara Bélanger, and Valérie Bédirian for helping with data collection and François Labelle for drawing the pictures. We also thank Patrick Bonin and an anonymous reviewer for their comments on an earlier version of this article. Correspondence concerning this article should be addressed to H. Cohen,
The role of the frontal lobe in cross-modal visual-auditory processing has been documented in exp... more The role of the frontal lobe in cross-modal visual-auditory processing has been documented in experiments using incongruent/ congruent paradigms. In this study, 4 patients with left frontal World Health Organization Grade II glioma were assessed during pre-, intra-, and postoperative sessions with picture-naming and verbal-visual task requiring judgment of congruence between pictures and words. During awake brain surgery, the naming and crossmodal tasks were coupled with electrical stimulation inactivating restricted specific regions. For all patients, focal brain stimulation in the dorsolateral prefrontal cortex elicited picture-word matching disturbances but no naming impairment, and the elicited errors exclusively appeared in incongruent and not congruent conditions. The dissociation observed between correct picture naming and disturbed cross-modal judgment shows that electrical stimulation of a discrete cortical area within the left dorsolateral prefrontal cortex can inhibit the simultaneous processing of visual-verbal information without disturbing larger networks involved in the naming process.
The discussion of whether emotions are categorical in nature has loomed large ever since Darwin (... more The discussion of whether emotions are categorical in nature has loomed large ever since Darwin (1872) posited an evolutionary base for human emotion expressions. This discussion has traditionally conflated two issues. First, is emotion elicitation categorical, such that different emotions are associated with qualitatively different neural substrates, expressive reactions, action tendencies, and feeling states resulting in discrete emotional states? And second, is the perception of emotion expressions categorical, resulting in the use of discrete emotion labels? These questions have been traditionally conflated because research on the universal use of emotion labels for facial expressions became a cornerstone for the assumption of discrete emotions. In this chapter I present an overview of this discussion that concludes a middle stance in which some processes are dimensional and others categorical. Importantly, from a functional perspective the use of emotion categories by perceiver...
Changes in speech and voice are characteristic of both neurodegenerative and psychiatric disorder... more Changes in speech and voice are characteristic of both neurodegenerative and psychiatric disorders. The acoustic analysis of speech production of several common disorders related to central nervous system dysfunction is summarized here. A brief introduction to the neurobiology of speech production illustrates how the cerebral structures and neurotransmitters involved in neurologic (e.g., Parkinson disease) and psychiatric (e.g., depression) disturbances contribute to specific speech alterations. A succinct overview of voice recording and data processing equipment is also provided.
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