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Biomedical subjects

D Van Lancker

Publications and source records attributed to D Van Lancker.

18 recordsLinked to original sources
PubMed2001

Impaired perception of vocal emotions in Parkinson's disease: influence of speech time processing and executive functioning.

Little is known about the underlying dimensions of impaired recognition of emotional prosody that is frequently observed in patients with Parkinson's disease (PD). Because patients with PD also suffer from working memory deficits and impaired time perception, the present study examined the contribution of (a) working memory (frontal executive functioning) and (b) processing of the acoustic parameter speech rate to the perception of emotional prosody in PD. Two acoustic parameters known to be important for emotional classifications (speech duration and pitch variability) were systematically varied in prosodic utterances. Twenty patients with PD and 16 healthy controls (matched for age, sex, and IQ) participated in the study. The findings imply that (1) working memory dysfunctions and perception of emotional prosody are not independent in PD, (2) PD and healthy control subjects perceived vocal emotions categorically along two acoustic manipulation continua, and (3) patients with PD show impairments in processing of speech rate information.

Affect↗
PubMed2001

Cerebral laterality for famous proper nouns: visual recognition by normal subjects.

Lexical processing has long been associated with left-hemisphere function, especially for infrequently occurring words. Recently, however, persons with severe aphasia, including word-recognition deficits, were observed to recognize familiar proper nouns. Further, some patients suffering right-hemisphere damage were poorer at identifying famous names than left-hemisphere-damaged subjects. These observations point to the possibility that some property of the right hemisphere provides an advantage for the processing of familiar or personally relevant stimuli. To investigate this possibility, we conducted split-visual-field studies in which we manipulated stimulus sets, recognition task, and exposure duration. Greater accuracy in the right visual field was found for common nouns and unknown proper nouns, and famous proper nouns were overall more accurately recognized. Performance for famous nouns in the two visual fields was not significantly different when the task required categorization into famous or nonfamous and when stimuli most highly rated as familiar were used. These findings support our proposals that (1) both hemispheres can process famous proper nouns and (2) the right hemisphere is specialized for personal relevance.

Adolescent↗
PubMed2000

A crosslinguistic PET study of tone perception.

In studies of pitch processing, a fundamental question is whether shared neural mechanisms at higher cortical levels are engaged for pitch perception of linguistic and nonlinguistic auditory stimuli. Positron emission tomography (PET) was used in a crosslinguistic study to compare pitch processing in native speakers of two tone languages (that is, languages in which variations in pitch patterns are used to distinguish lexical meaning), Chinese and Thai, with those of English, a nontone language. Five subjects from each language group were scanned under three active tasks (tone, pitch, and consonant) that required focused-attention, speeded-response, auditory discrimination judgments, and one passive baseline as silence. Subjects were instructed to judge pitch patterns of Thai lexical tones in the tone condition; pitch patterns of nonspeech stimuli in the pitch condition; syllable-initial consonants in the consonant condition. Analysis was carried out by paired-image subtraction. When comparing the tone to the pitch task, only the Thai group showed significant activation in the left frontal operculum. Activation of the left frontal operculum in the Thai group suggests that phonological processing of suprasegmental as well as segmental units occurs in the vicinity of Broca's area. Baseline subtractions showed significant activation in the anterior insular region for the English and Chinese groups, but not Thai, providing further support for the existence of possibly two parallel, separate pathways projecting from the temporo-parietal to the frontal language area. More generally, these differential patterns of brain activation across language groups and tasks support the view that pitch patterns are processed at higher cortical levels in a top-down manner according to their linguistic function in a particular language.

Adult↗
PubMed1999

Expletives: neurolinguistic and neurobehavioral perspectives on swearing.

Severe aphasia, adult left hemispherectomy, Gilles de la Tourette syndrome (GTS), and other neurological disorders have in common an increased use of swearwords. There are shared linguistic features in common across these language behaviors, as well as important differences. We explore the nature of swearing in normal human communication, and then compare the clinical presentations of selectively preserved, impaired and augmented swearing. These neurolinguistic observations, considered along with related neuroanatomical and neurochemical information, provide the basis for considering the neurobiological foundation of various types of swearing behaviors.

Behavior↗
PubMed1997

Rags to riches: our increasing appreciation of cognitive and communicative abilities of the human right cerebral hemisphere.

Studies of right hemisphere abilities have grown from focusing on visuospatial and facial recognition in the 1950s to covering a broad spectrum of human behavior. The emergence of better understanding of auditory specializations, affective/emotional functions, personal relevance, idiosyncratic lexical organization, and the various aspects of language use--communicative pragmatics--is briefly reviewed.

Brain↗
PubMed1994

Influence of language structure on brain-behavior development.

Lack of exposure to specific sensory patterns during critical periods of development can result in a lack of responsiveness to those stimuli in adulthood. The present study extends these observations to native speakers of Japanese, a language which does not contain the contrastive /r/ and /l/ sounds present in English. Both electrophysiological (P3 event-related evoked potential) and behavioral results indicate deficient or absent discrimination of /r/ versus /l/ sounds in Japanese adults compared to native speakers of English. Thus, language structure appears to provide a subtle yet measurable effect on specific aspects of brain development and function.

Adult↗
PubMed1992

The identification of affective-prosodic stimuli by left- and right-hemisphere-damaged subjects: all errors are not created equal.

Impairments in listening tasks that require subjects to match affective-prosodic speech utterances with appropriate facial expressions have been reported after both left- and right-hemisphere damage. In the present study, both left- and right-hemisphere-damaged patients were found to perform poorly compared to a nondamaged control group on a typical affective-prosodic listening task using four emotional types (happy, sad, angry, surprised). To determine if the two brain-damaged groups were exhibiting a similar pattern of performance with respect to their use of acoustic cues, the 16 stimulus utterances were analyzed acoustically, and the results were incorporated into an analysis of the errors made by the patients. A discriminant function analysis using acoustic cues alone indicated that fundamental frequency (FO) variability, mean FO, and syllable durations most successfully distinguished the four emotional sentence types. A similar analysis that incorporated the misclassifications made by the patients revealed that the left-hemisphere-damaged and right-hemisphere-damaged groups were utilizing these acoustic cues differently. The results of this and other studies suggest that rather than being lateralized to a single cerebral hemisphere in a fashion analogous to language, prosodic processes are made up of multiple skills and functions distributed across cerebral systems.

Adult↗
PubMed1991

Personal relevance and the human right hemisphere.

Brain damage can selectively disrupt or distort information and ability across the range of human behaviors. One domain that has not been considered as an independent attribute consists of acquisition and maintenance of personal relevant entities such as "familiar" faces, persons, voices, names, linguistic expressions, handwriting, topography, and so on. In experimental studies of normal mentation, personal relevance is revealed in studies of emotion, arousal, affect, preference and familiarity judgments, and memory. Following focal brain damage, deficits and distortions in the experience of personal relevance, as well as in recognizing formerly personally relevant phenomena, are well known to occur. A review and interpretation of these data lead to a proposal that the right hemisphere has a special role in establishing, maintaining, and processing personally relevant aspects of the individual's world.

Agnosia↗
PubMed1990

Preserved recognition of familiar personal names in global aphasia.

Recognition of proper and common nouns was compared in four patients diagnosed with global aphasia secondary to ischemic left-hemisphere infarction. For proper noun recognition, subjects matched the spoken or written name of a famous person to a photograph, and for common nouns, subjects were tested on standardized and special word recognition tests. As expected, common noun recognition was severely compromised in the aphasic patients. In contrast, familiar personal names, despite their greater length and complexity, were recognized equally well by aphasic and normal control subjects. The right hemisphere may mediate the ability to recognize personally familiar names, as it may be specialized for establishing personally relevant environmental stimuli.

Aged↗
PubMed1988

Hemispheric specialization for voice recognition: evidence from dichotic listening.

To measure lateralization of voice recognition abilities in normal subjects, listeners identified both the speaker (a famous male) and the word spoken on each trial in a dichotic listening paradigm. The voice identification task resulted in a zero ear advantage, which differed significantly from the significant right ear advantage found for word identification. This suggests that voice and word information, although carried in the same auditory signal, engage different cerebral mechanisms.

Attention↗
PubMed1988

Proverb and idiom comprehension in Alzheimer disease.

Twenty-nine patients diagnosed with Probable Alzheimer Disease were administered tests of word, familiar phrases (idioms and proverbs), and novel phrase comprehension. From the early stage of the disease, patients performed worse at understanding familiar phrases than single words or novel phrases. The results uphold common observations that AD patients have difficulty interpreting abstract meanings. Cognitive variables responsible for poor idiom/proverb comprehension and the clinical implications of this new protocol are discussed.

Aged↗
PubMed1987

Voice discrimination and recognition are separate abilities.

Studies of brain-damaged subjects indicate that recognizing a familiar voice and discriminating among unfamiliar voices may be selectively impaired, and thus that the two are separate functions. Familiar voice recognition was impaired in cases of damage to the right (but not the left) hemisphere, while impaired unfamiliar voice discrimination was observed in cases with damage to either hemisphere.

Adult↗
PubMed1981

Idiomatic versus literal interpretations of ditropically ambiguous sentences.

"Ditropically" ambiguous sentences (each having both a literal and an idiomatic interpretation) were prepared for listener's discrimination judgments, and for silent readers' rankings on an "idiomaticity" scale. Listeners were unable to discriminate the literal from the idiomatic versions when presented with randomized single sentences excised from paragraph contexts. There was a bias toward interpreting the sentences as idioms, which correlated with rankings of each sentence for its likelihood of idiomatic use. Listeners were easily able to identify the literal and the idiomatic versions of the same ditropic sentences presented in pairs or singularly, when speakers sought purposively to convey the contrasting meanings.

Humans↗
PubMed1981

Disambiguation of ditropic sentences: acoustic and phonetic cues.

In a previous study, we demonstrated that listeners were highly successful in identifying the intended meaning of spoken ditropic sentences (those which may carry either a literal or an idiomatic meaning) when speakers were instructed to convey the distinction. The present communication reports on acoustic and phonetic analyses carried out with the goal of identifying cues that distinguished the literal and idiomatic utterances. Certain prosodic differences were observed. Literal utterances were systematically longer than idioms. This was partly due to increased use of pauses, as well as to increased duration of major lexical items. Moreover, literal sentences were typically characterized by greater numbers of pitch contours (discernible rise-fall excursions of fundamental frequency) and open junctures than were idiomatic utterances. In addition to suprasegmental contrasts, articulatory distinctions--corresponding to lento-allegro phonological rules--were also observed. These distinctions directly reflect the structural differences intrinsic to the two types of utterances. A literal sentence is formulated by the organization of constituent words and phrases. Idioms, on the other hand, are holistic units, largely nontransparent to syntactic structure or the usual meaning of the lexical members.

Humans↗
PubMedDate not supplied

Midlatency auditory evoked responses: differential abnormality of P1 in Alzheimer's disease.

The human 'P1' middle latency evoked potential is postulated to be generated in the thalamus by a cholinergic component of the ascending reticular activating system. To test the hypothesis that P1 and its generator substrate are abnormal in Alzheimer's disease (AD), a disorder of marked cholinergic deficiency, recordings of middle latency responses to click stimuli were carried out. Comparisons between the AD and age-matched control groups indicated normal auditory brain-stem and Pa responses but a significant decrease in P1 amplitude. This P1 abnormality suggests that the midbrain cholinergic cells in AD may be dysfunctional.

Adult↗
PubMedDate not supplied

P3 responses to prosodic stimuli in adult autistic subjects.

Autistic persons are known to have serious abnormalities in speech prosody. The present study attempted to ascertain whether autistic persons could discriminate and/or recognize prosodic contrasts in auditory stimuli. A group of 11 adult autistic subjects with normal IQ and an age-matched group of normal subjects were studied electrophysiologically and behaviorally during presentations of prosodic and phonemic stimuli. The cognitive P3 potential was recorded in response to rare (20%)/frequent (80%) presentations of phonemic stimuli, 'ba/pa,' linguistic-prosodic stimuli, 'Bob.' (statement)/'Bob?' (question), and emotional-prosodic stimuli, 'Bob' (happy)/'Bob' (angry). Behaviorally, auditory discrimination was tested by requiring a button-press response to each presentation of the rare target stimulus and cognitive association was tested by requiring a match between the verbalized stimulus and an appropriate picture/word. Contrary to our hypothesis, the autistic subjects generally showed normal P3 responses to all stimuli and performed at a normal level in all behavioral tests. However, a significant autistic P3 response to the phoneme 'pa' was not demonstrated. This surprising result was reexamined and shown to reflect an unusually large autistic response to 'pa' as the frequent stimulus in the first recording block, this initial hyper-reactivity prevented a 'frequent/rare' differential when 'pa' was presented as the rare stimulus in a later recording block. In the P3 latency window, both the autistic and control groups showed the largest amplitude responses to emotional-prosodic stimuli; neither the N1 nor P2 showed these stimulus effects. Thus, 'emotional sounds' appear to be particularly effective in activating the neural substrate of the P3 generator system. Overall, these data indicate remarkably normal P3 and behavioral processing of prosodic stimuli by the high-functioning autistic subjects of this study.

Acoustic Stimulation↗
PubMedDate not supplied

Midlatency auditory evoked responses: P1 abnormalities in adult autistic subjects.

MLR recordings from a group of 11 high-functioning adult autistic subjects were compared with those from a control group of 11 normal subjects. Components selected for analysis were "Pa", the maximum positivity in the 25-40 msec latency range following stimulus onset, "P1", the maximum positivity within the 50-65 msec latency range, and "Nb," the maximum negative deflection in the 40-50 msec latency range. Statistical analyses of amplitude and latency data were conducted using repeated measures analysis of variance and t test group comparisons. The Pa component showed no significant difference between autistic and control groups. However, 2 types of abnormality were noted in the P1 component: (1) the P1 component was significantly smaller in the autistic subjects at slow rates of stimulation, and (2) the autistic P1 did not change as rates of click stimulation increased from 0.5 to 10/sec, in contrast to the normally produced P1 decrement. Data from the P1 model in the cat, and complementary data from the human, closely link the generator substrate of the P1 potential to cholinergic components of the ascending reticular activating system (RAS) and their thalamic target cells. This is the first report of abnormal P1 responses in autism and strongly suggests that the RAS and/or its post-synaptic thalamic targets may be dysfunctional in this syndrome.

Acoustic Stimulation↗