Clinical Assessment of Pitch Perception *†Bart Vaerenberg, ‡Alexandru Pascu, §Luca Del Bo, *Karen Schauwers, *Geert De Ceulaer, *Kristin Daemers, *kMartine Coene, and *kPaul J. Govaerts *The Eargroup, Antwerp-Deurne; ÞLaboratory of Biomedical Physics, University of Antwerp, Antwerp, Belgium; þUniversity of Bucharest, Bucharest, Romania; §Fondazione Ascolta e Vivi, Milano, Italy; and kCentre for Computational Linguistics and Psycholinguistics, University of Antwerp, Antwerp, Belgium Objective: The perception of pitch has recently gained atten- tion. At present, clinical audiologic tests to assess this are hardly available. This article reports on the development of a clinical test using harmonic intonation (HI) and disharmonic intonation (DI). Study Design: Prospective collection of normative data and pilot study in hearing-impaired subjects. Setting: Tertiary referral center. Patients: Normative data were collected from 90 normal-hearing subjects recruited from 3 different language backgrounds. The pilot study was conducted on 18 hearing-impaired individuals who were selected into 3 pathologic groups: high-frequency hearing loss (HF), low-frequency hearing loss (LF), and cochlear implant users (CI). Intervention(s): Normative data collection and exploratory di- agnostics by means of the newly constructed HI/DI tests using intonation patterns to find the just noticeable difference (JND) for pitch discrimination in low-frequency harmonic complex sounds presented in a same-different task. Main Outcome Measure(s): JND for pitch discrimination using HI/DI tests in the hearing population and pathologic groups. Results: Normative data are presented in 5 parameter statistics and box-and-whisker plots showing median JNDs of 2 (HI) and 3 Hz (DI). The results on both tests are statistically abnormal in LF and CI subjects, whereas they are not significantly abnormal in the HF group. Conclusion: The HI and DI tests allow the clinical assessment of low-frequency pitch perception. The data obtained in this study define the normal zone for both tests. Preliminary results indicate possible abnormal TFS perception in some hearing- impaired subjects. Key Words: A§EVClinicalVPerceptionV PitchVTemporal fine structure. Otol Neurotol 32:736Y741, 2011. Pitch is an attribute of sound that has been shown to be important for both music perception and the quality of speech perception (1,2). By allowing us to order sounds on the low-high dimension, pitch carries essential infor- mation about the tonality and melody in music and about the linguistic context of words and sentences in spoken language (e.g., clause typing) (3,4). Like loudness relates to sound intensity, pitch relates to the frequency content of sounds. In daily life, the relevant cues for voicing, melody, intonation, and other musically and linguistically important percepts are conveyed by relatively low fre- quency pitch, relating mainly to the fundamental fre- quency or F0. The fundamental frequencies of several competing voices in a noisy environment, for example, allow us to distinguish between separate speakers (5). The way the cochlea codes spectral content of sound can be explained by 2 underlying mechanisms, place coding and phase locking. Both are complementary and overlapping. It is believed that for low-frequency signals, such as the fundamental frequencies of human voices, phase locking of the temporal pattern of nerve responses to the tempo- ral fine structure of the signal is the more dominant cue for conveying pitch. With increasing frequencies, this neural synchronicity becomes more difficult to be main- tained. Place coding then comes gradually into play and replaces the phase locking as mechanism for spectral dis- crimination (2). In the clinic, hearing assessment often is restricted to measures of detection (e.g., tone audiometry) or identi- fication (e.g., speech audiometry). Clinical tests allowing more fine-grained analysis of the coding of the differ- ent components of sound, like spectral discrimination, are rare, and to the best of our knowledge, no tests exist that focus on the capacity of the auditory system to dis- criminate pitch. The absence of such tests may not have been a problem so far. However, with the emergence of new therapeutic options for sensorineural hearing loss, like cochlear implants, electroacoustic stimulation, or even molecular or genetic therapies, the need for such tests may Address correspondence and reprint requests to Paul J. Govaerts, M.D., M.S., Ph.D., The Eargroup, Herentalsebaan 75, B-2100 Antwerp- Deurne, Belgium; E-mail: dr.govaerts@eargroup.net Support: The first author (B. V.) received a Ph.D. grant for this work from the IWT (Agentschap voor innovatie door Wetenschap en Tech- nologie, Baekeland-mandaat IWT090287). Otology & Neurotology 32:736Y741 Ó 2011, Otology & Neurotology, Inc. 736 Copyright © 2011 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.