Browsing by Author "Marques-Teixeira, João"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
- Abnormal habituation of the auditory event-related potential P2 component in patients with schizophreniaPublication . Mazer, Prune; Macedo, Inês; Paiva, Tiago O.; Ferreira-Santos, Fernando; Paison, Rita; Barbosa, Fernando; Almeida, Pedro; Silveira, Celeste; Cunha-Reis, Cassilda; Marques-Teixeira, JoãoAuditory event-related potentials (ERP) may serve as diagnostic tools for schizophrenia and inform on the susceptibility for this condition.Particularly, the examination of N1 and P2 components of the auditory ERP may shed light on the impairments of information processing streams in schizophrenia. However, the habituation properties (i.e., decreasing amplitude with the repeated presentation of an auditory stimulus) of these components remain poorly studied compared to other auditory ERPs.
- Auditory event-related potentials in autism with generalized epilepsy and family members: case reportPublication . Coutinho, Susana; Tomé, David; Lopes, Paula; Marques-Teixeira, JoãoLast fifteen years revealed an exponential growth in endophenotype and biomarkers research field in autism and epilepsy. The main goal seems to establish the relationship between neurobiological processes underlying pathological mechanisms and clinical expression, to define better treatment strategies but also accurate diagnosis. Comorbidity of autism with epilepsy occurs in 30% of cases. However, little is known on the common neurophysiopathological mechanisms and possible biomarkers. Very scarcely is known concerning auditory event-related potentials (AERPs) as possible biomarkers of autism associated with epilepsy. Our aim is to explore putative neuropsychophysiological trait markers in a case study of autism with generalized epilepsy, and its unaffected family members compared to a control group.
- Differences in Mismatch Negativity (MMN) response to Pure-tone and Speech sounds in normal subjects: an additional explanationPublication . Tomé, David; Barbosa, Fernando; Marques-Teixeira, JoãoThe relation of automatic auditory discrimination, measured with MMN, with the type of stimuli has not been well established in the literature, despite its importance as an electrophysiological measure of central sound representation. In this study, MMN response was elicited by pure-tone and speech binaurally passive auditory oddball paradigm in a group of 8 normal young adult subjects at the same intensity level (75 dB SPL). The frequency difference in pure-tone oddball was 100 Hz (standard = 1 000 Hz; deviant = 1 100 Hz; same duration = 100 ms), in speech oddball (standard /ba/; deviant /pa/; same duration = 175 ms) the Portuguese phonemes are both plosive bi-labial in order to maintain a narrow frequency band. Differences were found across electrode location between speech and pure-tone stimuli. Larger MMN amplitude, duration and higher latency to speech were verified compared to pure-tone in Cz and Fz as well as significance differences in latency and amplitude between mastoids. Results suggest that speech may be processed differently than non-speech; also it may occur in a later stage due to overlapping processes since more neural resources are required to speech processing.
- Mismatch negativity in childhood temporal lobe epilepsy: a proposed paradigm for testing central auditory processingPublication . Tomé, David; Moreira, Pedro; Marques-Teixeira, João; Barbosa, Fernando; Jääskeläinen, SatuBackground: Temporal lobe epilepsy (TLE) is a neurological disorder that directly affects cortical areas responsible for auditory processing. The resulting abnormalities can be assessed using event-related potentials (ERP), which have high temporal resolution. However, little is known about TLE in terms of dysfunction of early sensory memory encoding or possible correlations between EEGs, linguistic deficits, and seizures. Mismatch negativity (MMN) is an ERP component – elicited by introducing a deviant stimulus while the subject is attending to a repetitive behavioural task – which reflects pre-attentive sensory memory function and reflects neuronal auditory discrimination and perceptional accuracy. Hypothesis: We propose an MMN protocol for future clinical application and research based on the hypothesis that children with TLE may have abnormal MMN for speech and non-speech stimuli. The MMN can be elicited with a passive auditory oddball paradigm, and the abnormalities might be associated with the location and frequency of epileptic seizures. Significance: The suggested protocol might contribute to a better understanding of the neuropsychophysiological basis of MMN. We suggest that in TLE central sound representation may be decreased for speech and non-speech stimuli. Discussion: MMN arises from a difference to speech and non-speech stimuli across electrode sites. TLE in childhood might be a good model for studying topographic and functional auditory processing and its neurodevelopment, pointing to MMN as a possible clinical tool for prognosis, evaluation, follow-up, and rehabilitation for TLE.
- Temporal lobe epilepsy in childhood – a study model of auditory processingPublication . Tomé, David; Marques-Teixeira, João; Barbosa, FernandoTLE in infancy has been the subject of varied research. Topographical and structural evidence is coincident with the neuronal systems responsible for auditory processing of the highest specialization and complexity. Recent studies have been showing the need of a hemispheric asymmetry for an optimization in central auditory processing (CAP) and acquisition and learning of a language system. A new functional research paradigm is required to study mental processes that require methods of cognitive-sensory information analysis processed in very short periods of time (msec), such as the ERPs. Thus, in this article, we hypothesize that the TLE in infancy could be a good model for topographic and functional study of CAP and its development process, contributing to a better understanding of the learning difficulties that children with this neurological disorder have.