[Aphasia and facial paralysis after peribulbar anesthesia].
Explore the source record for details and available documents.
Aged↗
Biomedical subjects
M Cheour
Publications and source records attributed to M Cheour.
[Retrospective study on 100 cases of infective endocarditis, Rabta University Hospital, Tunis, from 1980 to 2004].
This retrospective study describes 100 cases of infective endocarditis (IE), collected between 1980 and 2004. Patients were subdivided into 2 groups, according to the use of trans-esophageal echocardiography (TOE) in the institution where the study was performed: group A (GA=55 patients, between 1980 and 1991) and group B (GB=45 patients, between 1992 and 2004). The IE cases of 59 men and 41 women were analyzed. Patients had a mean age of 33 years (range 15-75 years). An underlying heart disease was involved in all cases, mainly rheumatic heart disease (93% of cases). Native valve endocarditis (NVE) was seen in a majority of cases (93%), and the localization of IE was aortic in 36 cases, mitral in 36 cases, mitro-aortic in 26 cases and mitro-aortic-tricuspid in 2 cases. Prosthetic valve endocarditis (PVE) occurred in 12 cases. Blood cultures were positive in 31 cases, with 14 staphylococcal infections (3 in GA and 11 in GB) (p < 0.05), of which 6 were coagulase-negative; 13 were streptococci and 4 were Gram negative bacilli. All patients had a transthoracic echocardiography (TTE), and patients in group B also had a TOE. Seventeen patients had a favorable outcome without need of a surgical intervention. Early surgery was necessary in 71 cases (85.5%), and elective surgery in 12 cases (14.5%). Mortality while awaiting surgery was 27%, and has been decreasing for the past decade (41.8% in GA and 8.9% in GB) [p < 0.05]. Postoperative mortality after early surgery intervention was 13.6% (6 among 44 patients), and it was 8.3% (1 among 12 patients) after elective surgery intervention. Overall mortality was 34%: 27 deaths with NVE (30.7% [27/88]), and 7 deaths with PVE (58.3% [7/12]) [NS]. Predictors of mortality in this observational study were positive blood cultures involving staphylococci, the presence of valve mutilations, unstable prostheses, and heart failure.
Adolescent↗
Speech sounds learned by sleeping newborns.
It is not yet clear whether humans are able to learn while they are sleeping. Here we show that full-term human newborns can be taught to discriminate between similar vowel sounds when they are fast asleep. It is possible that such sleep training soon after birth could find application in clinical or educational situations.
Humans↗
Central auditory processing of durational changes in complex speech patterns by newborns: an event-related brain potential study.
In this study, newborns' ability to discriminate durational changes in the fricative /s/ within a nonsense word was investigated. The results showed that infrequent increments and decrements of a speech sound duration elicit a mismatch negativity kind of response in sleeping human newborns. In the auditory event-related potential to these deviant stimuli two negative waves of this response were revealed. The first negative wave peaked at about 150 msec and the second at about 350 msec after the change onset. At least one negative deflection, which was interpreted as evidence for stimulus change-detection, was observed in every infant.
Adult↗
Increased distractibility in closed head injury as revealed by event-related potentials.
The present study demonstrates that event-related potentials (ERPs) may be used to reveal increased distractibility as a physiologically measurable condition after chronic closed head injury (CHI). ERPs were recorded from 17 chronic CHI subjects and from 17 healthy age-matched controls. Auditory stimuli consisted of variants of vowel /o/ (standards) occasionally replaced by an /e/ vowel (deviant). Subjects were instructed to ignore auditory stimuli while watching a silent movie. In the constant-standard condition, the vowel /o/ served as the standard and vowel /e/ as the deviant. In the roving-standard condition, four variants of the vowel /o/ were randomly used as standards in the same stimulus block. None of the stimuli were prototypes in the subjects' mother tongues. Deviant stimuli elicited significant MMNs in both groups in both conditions, which were significantly smaller in the roving-standard than in the constant-standard condition. CHI victims showed significantly larger P3a amplitudes than controls in both conditions, apparently reflecting their enhanced involuntary sifting of attention and thus their increased distractibility.
Acoustic Stimulation↗
Mismatch negativity (MMN) as a tool for investigating auditory discrimination and sensory memory in infants and children.
For decades behavioral methods, such as the head-turning or sucking paradigms, have been the primary methods to investigate auditory discrimination, learning and the function of sensory memory in infancy and early childhood. During recent years, however, a new method for investigating these issues in children has emerged. This method makes use of the mismatch negativity (MMN), the brain's automatic change-detection response, which has been used intensively in both basic and clinical studies in adults for twenty years. This review demonstrates that, unlike many other components of event-related potentials, the MMN is developmentally quite stable and can be obtained even from pre-term infants. Further, MMN amplitude is only slightly smaller in infants than is usually reported in school-age children and it does not seem to differ much from that obtained in adults. MMN latency has been reported to be slightly longer in infants than in adults but reaches adult values by the early school-age years. Child MMN does not seem to be analogous to adult MMN, however. For example, contrary to the results of adult studies, a prominent MMN can be obtained from in all waking- and sleep states in infants. Moreover, MMN scalp distribution seems to be broader and more central in children than in adults.
Adult↗
Dysfunction of the auditory cortex persists in infants with certain cleft types.
Language and learning disabilities occur in almost half of individuals with oral clefts. The characteristics of these cognitive dysfunctions vary according to the cleft type, and the mechanisms underlying the relation between cleft type, cognitive dysfunction, and cleft-caused middle-ear disease are unknown. This study investigates preattentive auditory discrimination, which plays a significant role in language acquisition and usage, in infants with different cleft types. A mismatch negativity (MMN) component of brain evoked potentials, which indexes preconscious sound discrimination, and brain responses to rare sine-wave tones were recorded in 12 healthy infants and 32 infants with oral clefts at the ages of 0 and 6 months. Infants with clefts were subdivided into two categories: those with cleft lip and palate (CLP) (n=11 at birth, n=6 at the age of 6 months) and those with cleft palate only (CPO) (n=17 at birth, n=8 at the age of 6 months). At both ages, brain responses to rare sounds tended to be smaller in both cleft subgroups than in healthy peers. However, in the latency range of 300 to 500 ms, the MMN was significantly smaller in infants with CPO. In infants with CLP, the MMN was comparable to that of healthy infants. Differences in auditory discrimination between infants with CLP and CPO, as reflected by MMN, were detectable at birth and persisted into later infancy. This pattern parallels known behavioural differences between children with these cleft types. Brain responses to rare sounds, in contrast, had no differentiative power with respect to the cleft type.
Auditory Cortex↗
[Auditory event related brain potentials in the research of brain development and its disorders].
Explore the source record for details and available documents.
Acoustic Stimulation↗
Cortical responses of infants with and without a genetic risk for dyslexia: I. Age effects.
We studied auditory event-related potentials (ERP) in newborns and 6-month-old infants, about half of whom had a familial risk for dyslexia. Syllables varying in vowel duration were presented in an oddball paradigm, in which ERPs to deviating stimuli are assumed to reflect automatic change detection in the brain. The ERPs of newborns had slow positive deflections typical of their age, but significant stimulus and group effects were found only by the age of 6 months. In both groups, the responses to the deviant /ka/ were more positive than those to the standard /kaa/ stimuli, contrary to the findings of adult ERPs to duration changes. The results also suggested differences in brain activation pattern between the groups.
Acoustic Stimulation↗
Brain dysfunction in neonates with cleft palate revealed by the mismatch negativity.
OBJECTIVES: Our recent studies have demonstrated that the brain's automatic change-detection response, the mismatch negativity (MMN) of the event-related brain potential (ERP), is significantly attenuated in school-age children with CATCH syndrome and in children of the same age with cleft palate but without the CATCH syndrome. Among other problems, various kinds of learning difficulties are commonly reported in these patient groups. The present study aimed at investigating whether the MMN is attenuated already in newborns with cleft palate compared with healthy controls. METHODS: Stimuli of 1000 Hz were presented frequently and 1100 Hz infrequently to 9 neonates with cleft palate and to 8 healthy controls. Infrequent 1100 Hz stimuli elicited a prominent MMN in all of the healthy children, but only in 3 of the 9 infants with cleft palate. RESULTS: A significant difference in the mean amplitudes of responses to deviant tones between the healthy and cleft palate neonates was found. CONCLUSIONS: MMN may indicate brain dysfunctions long before they have manifested themselves in cognitive disabilities, which would enable one to identify the infants with an elevated risk and to start their rehabilitation much earlier than before.
Acoustic Stimulation↗
Cortical auditory dysfunction in children with oral clefts: relation with cleft type.
OBJECTIVE: Up to 46% of individuals with oral clefts suffer from language-learning disabilities. The degree of these disabilities varies according to cleft type. The pathogenesis of cognitive malfunctioning or its relationship with cleft type is not known. We investigated persistence of auditory short-term memory (STM) that is implicitly involved in language-specific perception in children with clefts, grouped using fine-graded cleft classification. METHODS: Cortical evoked potentials were recorded in 78 children with non-syndromic oral clefts and in 32 healthy peers. A mismatch negativity (MMN) potential that indexes preattentive detection of change in auditory input was obtained in response to tone sounds. In order to test durability of short-term memory traces, sounds were presented with three stimulation rates. RESULTS: With slowest stimulation, MMN amplitudes were reduced in cleft children as compared to the healthy peers (P < 0.00065). Only cleft-lip children did not significantly differ from controls. Among isolated palatal clefts, the more posteriorly delimited the cleft was, the smaller was the amplitude of MMN. MMNs of smallest amplitudes were obtained in the subgroup of complete unilateral cleft of lip and palate. CONCLUSIONS: Reduced MMN amplitudes, found in cleft children, imply deficiency in auditory STM trace maintenance. This dysfunction is likely to contribute to their language and learning disabilities. The MMN diminution with shorter/more posterior clefts suggests that differences in auditory cortex function are one of the underlying mechanisms of the cleft type-malcogniton association.
Acoustic Stimulation↗
Children's performance on pseudoword repetition depends on auditory trace quality: evidence from event-related potentials.
This study explored the relation between phonological short-term memory and auditory-sensory processing in 7-9-year-old children. Twenty-four participants performed a pseudoword repetition test. The mismatch-negativity (MMN) component of auditory event-related brain potentials was obtained from 9 participants with the highest and 9 participants with the lowest scores on the test. The MMN indexes short-term auditory-sensory memory, including auditory-sensory representations for speech. It was recorded to just perceptible /baga/-/baka/ bisyllabic and easily discriminable 1000/1100-Hz tone contrasts with interstimulus intervals of 350 and 2,000 ms. The high and low repeaters differed significantly in MMN amplitude to speech stimuli at the shorter interstimulus interval. Thus, the accuracy of auditory-sensory processing seems to affect phonological short-term representations in school-age children and therefore may play a role in vocabulary development.
Child↗
[Retinal artery occlusion during disseminated lupus erythematosus].
Retinal vascular disease in lupus is the most common ophthalmic manifestation, but retinal neovascularization is rare. We report a patient with sytemic lupus erythematosus and retinal neovascularization caused by branch retinal artery occlusion.
Adult↗
[Therapeutic strategies in the first psychotic episode].
A first psychotic episode includes a wide range of disorders with different outcomes: schizophrenia, bipolar disorder, schizophreniform disorder, schizoaffective disorder, drug-induced psychosis, brief reactive psychosis, organic psychoses and delusional disorder. The course and outcome of a first psychotic episode is greatly dependent on its initial management. Major clinical, etiopathogenic and therapeutic advances have been achieved in this field and have allowed specific management strategies to be adopted. The primary task of therapists involved in the management of patients who have experienced a first episode of psychosis is promotion of recovery and prevention of secondary morbidity, relapse and persistent disability. The main guidelines of an early psychosis management are:--to keep in mind that early psychosis is not early schizophrenia. Thus, clinicians and therapists should avoid an early diagnosis of schizophrenia. Diagnosis in early psychosis can be highly unstable. A diagnosis of schizophrenia, with its implications of pessimism, relapse and disability, does not contribute anything positive in terms of guiding treatment. On the contrary, such a diagnosis may damage the patient and family by stigmatizing them and affecting the way they are viewed and managed by healthcare professionals.--To integrate biological, psychological and social interventions: effective medications is useful in reducing the risk of relapse, but is not a guarantee against it. Psychological and social interventions can greatly help promote recovery.--To tailor the various strategies to met the needs of an individual: as an example, it is important to formulate appropriate strategies for the different stages of the illness (prodromal phase, acute phase, early recovery phase and late recovery phase) because patients have different therapeutic needs at each stage.--In the acute treatment, not to concentrate on short-term goals in indicating antipsychotic treatment: prescribing principles for first-episode psychosis are to maximise benefit and minimise side effects because the first experience of medication may influence a patient's future attitudes of therapy of all types. Effective strategies which may reduce long-term morbidity and improve recovery are currently available but their implementation is too often delayed. The time lag between the onset of symptoms and the start of treatment can be many months or years and this delay can have serious consequences. The critical period of the first 2-5 years after the first psychotic episode is a time of maximum vulnerability and of maximum opportunity. Consequently, actions should be undertaken to promote early recognition and assistance in psychotic disorders: understanding of the factors that may cause delay in treatment can help minimise this problem and lead to the initiation of appropriate treatment at the earliest opportunity. Training the general practitioners who have an important part to play in the early recognition is also of crucial importance.
Acute Disease↗
Hemispheric lateralization in preattentive processing of speech sounds.
Event-related magnetoencephalographic (MEG) responses to infrequently presented spoken deviant syllables [di] and [ba] among repetitive standard [da)]syllables were recorded in subjects who either attended to these stimuli in order to discriminate the [ba] syllables or ignored them while attending a silent movie. In both conditions, the deviant syllables elicited a mismatch response (MMNm, the magnetic counterpart of mismatch negativity), which was stronger in the left than in the right auditory cortex, indicating left-hemispheric dominance in speech processing already at a preattentive processing level.
Acoustic Stimulation↗
Mismatch negativity (MMN) as an index of auditory sensory memory deficit in cleft-palate and CATCH syndrome children.
Our recent study demonstrated with the brain's automatic change-detection response, the mismatch negativity (MMN) of the event-related potentials (ERPs), that the duration of auditory sensory memory is significantly shorter in school-age children with CATCH syndrome than in healthy age-matched controls. One of the characteristic symptoms of this syndrome, caused by a microdelection in chromosome 22, is cleft palate. The most common problems in these children, however, are learning difficulties and, according to our results, it is likely that these problems are not due to the dysmorphology of peripheral speech mechanisms only but are also caused by CNS dysfunctions. In the present study we show with MMN that auditory sensory memory is also shortened in school-age children with cleft palate but without the CATCH syndrome. It has been shown in previous studies with neuropsychological tests that although children with cleft palate have language and learning-related problems these difficulties are usually less severe than those of CATCH children. Likewise the present study demonstrates that the auditory sensory memory trace seems to decay more rapidly in CATCH children than in children with cleft palate.
Abnormalities, Multiple↗
Maturation of mismatch negativity in infants.
The mismatch negativity (MMN) is a pre-attentive change-specific component of the event-related brain potentials (ERPs). During the last decade this response has been intensively studied in adults, but investigations in children and especially in infants are still rare. Recent studies, however, have shown that MMN is also elicited in infants in response to changes in pure tones as well as in phonemes. The present study compared MMN in pre-term infants (conceptional age at the time of recording, 30-35 weeks), full-term newborns and full-term 3-month-old infants. Stimuli were Klatt-synthesized Finnish vowels /y/ and /i/. Previous studies have reported larger MMN amplitudes in school-age children compared with those obtained in adults. According to the results, however, the infant MMN amplitude seems to resemble that of adults. No significant differences in MMN amplitudes were found between the three age groups either. The mean MMN latency, however, decreased significantly with age, although in 3-month-old infants it was not much longer than in a previous study conducted in adults with the same stimuli.
Acoustic Stimulation↗
Interstimulus interval and auditory event-related potentials in children: evidence for multiple generators.
In the present study, the component structure of auditory event-related potentials (ERP) was studied in children of 7-9 years old by presenting stimuli with different interstimulus intervals (ISI). A short-term auditory sensory memory, as reflected by ISI effects on ERPs, was also studied. Auditory ERPs were recorded to brief unattended 1000 Hz frequent, 'standard' and 1100 Hz rare, 'deviant' (probability 0.1) tone stimuli with ISIs of 350, 700 and 1400 ms (in separate blocks). With the 350 ms-ISI, the ERP waveform to the standard stimulus consisted of P100-N250 peaks. With the two longer ISIs, in addition, the frontocentral N160 and N460 peaks were observed. Results suggested that N160, found with the longer ISIs, is a correlate of the adult auditory N1. In difference waves, obtained by subtracting ERP to standard stimuli from ERP to deviant stimuli, two negativities were revealed. The first was the mismatch negativity (MMN), which is elicited by any discriminable change in repetitive auditory input. The MMN data suggested that neural traces of auditory sensory memory lasted for at least 1400 ms, probably considerably longer, as no MMN attenuation was found across the ISIs used. The second, later negativity was similar to MMN in all aspects, except for the scalp distribution, which was posterior to that of the MMN.
Acoustic Stimulation↗