LABORATORY OF NEUROPSYCHOLOGY

| Head: Elżbieta SZELĄG, Ph.D., D.Sc. E-mail: e.szelag@nencki.gov.pl Staff: Joanna KOWALSKA, M.Sc. Ph.D. students: Magdalena KANABUS, M.Sc., Iwona KOŁODZIEJCZYK, M.Sc.

Research profiles concern neuropsychology of cognitive functions, including perception, language, emotions and movements. The studies are focused both on temporal aspects of information processing and hemispheric asymmetry. Research involves normal subjects (children and adults, including Polish centenarians), patients with focal brain damage, aphasics, cochlear implant users, and children who show various speech and/or language disorders, e.g. deafness, stuttering, infantile autism. Experiments on time and timing have focussed the scientific interests with respect to possibilities for practical applications in creating new methods of speech therapy.

The following research activities are currently represented in the Laboratory: time perception in patients with focal brain damage; temporal information processing in aphasic patients as a basis of language therapy; speech therapy in different language disorders; neuropsychology of language restitution in patients with cochlear implants; the effect of congenital deafness on temporal constraints of cognition; cognitive deficits in infantile autism; neuropsychology of normal chronological aging and longevity; temporal information processing in normal child development.

One of our main findings is an association between language deficits following brain damage and impairments in time perception. The results suggest that anterior and posterior lesions of the speech hemisphere are differently involved in temporal processing. The prolongation of information processing in the time domain of ca. 30-40 milliseconds (Fig.1), but normal processing on 2-3 second level, was characteristic for fluent aphasia (Wernicke). Patients with non-fluent aphasia (Broca) had impaired the range of seconds, whereas the millisecond level was comparable to controls. Thus, the selective temporal impairments were associated with the specific language deficits, characteristic for fluent and non-fluent aphasia.

The temporal processing deficits on these two levels were also observed in monochannel cochlear implant users who demonstrated severe auditory comprehension deficits. These patients showed the prolongation of information processing in the time domain of ca. 30-40 milliseconds (Fig.2), accompanied by deficits on 2-3 second level.

These findings indicate that language deficits of different etiology are associated with disorders in temporal information processing. The temporal impairments may constitute the basis for the modern method of speech therapy, rooted not only in the verbal level but also in the pre- linguistic one, related to time perception.

Fig.1. Auditory order thresholds for five patient groups with focal brain injuries and for an orthopaedic control group (controls): LH.pre - anterior left hemisphere with non-fluent aphasia; LH.post - posterior left hemisphere with fluent aphasia; L.noAph - left-sided subcortical lesions without aphasia, RH.pre - anterior right hemisphere; RH.post- posterior right hemisphere ( v. Steinbüchel N., Wittmann M., Strasburger H., Szelag E.; Auditory temporal-order judgement is impaired in patients with cortical lesions in posterior regions of the left hemisphere. Neurosci. Lett. 264:1999, 168-171)
Fig.2. The level of correct responses for identification of the order of two tones (300 and 3000 Hz) presented with different inter-stimulus-intervals in monochannel cochlear implant recipients and in normal- hearing subjects (Kanabus M., Szelag E., Szuchnik J., Kolodziejczyk I.; Auditory order threshold in cochlear implant recipients, in preparation)

Selected publications:

1. Szelag E., Kowalska J., Galkowski T., Pöppel E., (in preparation). Autism – a case of temporal neglect?

2. Wittman M., Szelag E., (2003). Sex differences in perception of temporal order. Perceptual and Motor Skills 96, 105-112;

3. Kanabus M., Szelag E., Rojek E., Pöppel E., (2002). Temporal order judgement for auditory and visual stimuli. Acta Neurobiologiae Experimentalis 62, 263-270

4. Szelag E., Kowalska J., Rymarczyk K., Pöppel E., (2002). Duration processing in children as determined by time reproduction: implications for a few seconds temporal window. Acta Psychologica 110, 1-19;

5. Szelag E., v.Steibüchel N., Pöppel E., (1997). Temporal processing disorders in patients with Broca’s aphasia. Neuroscience Letters 235, 33-36.