Deficits of non-verbal auditory perception in postlingually deaf humans using cochlear implants E. Szelag a, * , I. Kolodziejczyk a , M. Kanabus a , J. Szuchnik b , A. Senderski b a Laboratory of Neuropsychology, Department of Neurophysiology, Nencki Institute of Experimental Biology, 3 Pasteur Street, 02-093 Warsaw, Poland b Institute of Physiology and Pathology of Hearing, 1 Pstrowski Street, 01-943 Warsaw, Poland Received 27 June 2003; received in revised form 12 September 2003; accepted 15 October 2003 Abstract Temporal integration in the time domain of a few seconds was investigated with a subjective accentuation paradigm in 11 monochannel cochlear implant users, who showed auditory comprehension deficits. While listening to metronome beats generated at various frequencies, patients were asked to accentuate mentally every n-th beat and create an individual rhythmic pattern. The extent of temporal integration was defined as the duration of perceptual units consisting of subjectively grouped beats at particular metronome frequencies. The results indicate that there is reduced capacity for temporal integration in implant recipients, particularly for lower metronome frequencies, in comparison to normally hearing. These observations point to the coincidence of specific temporal processing disorders and deficits in auditory comprehension after cochlear implantation. q 2003 Elsevier Ireland Ltd. All rights reserved. Keywords: Cochlear implant; Timing; Temporal integration; Subjective rhythm Cochlear implant (CI) operation in post-lingually deafened adults restores hearing and allows recovery of speech comprehension. The operation involves the replacement of hair cells in the inner ear by electrodes, stimulating the auditory nerve directly. Although CI has a significant impact on auditory capacity, the restoration of speech comprehension in most of CI recipients develops over many months of implant use and only in conjunction with speech therapy [7,18]. The neuronal mechanisms underlying the restoration of comprehension are not explained in detail in the literature. Many research studies have now demonstrated the close relationship between temporal information processing (TIP) and language. At least two different temporal ranges appear to be crucial for language, namely a high-frequency level of ms range (related to single units of language-phonemes) and a low-frequency domain of a few seconds range (related to phrases). Whereas TIP impairment on the former level is documented in people with aphasia [16], language-impaired children [15] and CI users (see ref. [2] for a review), the latter level is still underrepresented. The present study focuses on this low-frequency level in CI recipients and addresses the temporal integration (TI), one of the hypothetical mechanisms occurring at the highest level in the taxonomy of time perception [9,10]. Accordingly, TI links individual successive events into a single perceptual unit, limited to approx. 2–3 s. Converging evidence suggests that TI defines a ‘working platform’ for human mental activities [9]. It can also play an important role in speech which is rhythmically programmed by hesitation pauses and fluent speech segments (phrases). The duration of such segments in several languages (i.e. German, Polish, Spanish, Chinese) is predominantly limited to ca. 2–3 s, probably as a result of this integration process [10,17]. The purpose of the present study was to test the limits of TI and to explore the possible relationships between TIP in the above time domain and comprehension in CI users. On the basis of our earlier papers [12–14], the extent of such integration was tested using the subjective rhythmisation paradigm. Eleven right-handed, postlingually deafened subjects (seven men, four women) after monochannel cochlear implantation (Med-El Comfort, five right and six left implants) and 2 years of speech therapy, participated in 0304-3940/03/$ - see front matter q 2003 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.neulet.2003.10.025 Neuroscience Letters 355 (2004) 49–52 www.elsevier.com/locate/neulet * Corresponding author. Tel.: þ48-22-659-8571 ext. 286; fax: þ 48-22- 822-5342. E-mail address: e.szelag@nencki.gov.pl (E. Szelag).