PERCEPTION OF MUSIC BY PATIENTS WITH COCHLEAR IMPLANTS Jaan Ross (Tartu and Tallinn) Inna V. Koroleva and Jelena A. Ogorodnikova (St. Petersburg)

PERCEPTION OF MUSIC BY PATIENTS WITH COCHLEAR IMPLANTS

Jaan Ross (Tartu and Tallinn)

Inna V. Koroleva and Jelena A. Ogorodnikova (St. Petersburg)

Paper presented at the Institut für Musikwissenschaft, Universität Graz, 14 March 2006 2

Cochlear implantation (1)Cochlear implantation is one of the most perspective directions in

the rehabilitation of patients with significant hearing losses

Cochlear implant is a surgically implantable device that provides hearing sensation to individuals with severe-to-profound hearing loss who do not benefit from hearing aids

People with hearing losses in such range have absent or malfunctioning sensory cells in the cochlea


Cochlear implantation (2)In a normal ear, sound energy is converted to mechanical energy by the middle ear, which is then converted to mechanical fluid motion in the cochlea. Within the cochlea, the sensory cells (the inner and outer hair cells) are sensitive transducers that convert that mechanical fluid motion into electrical impulses in the auditory nerve.


Cochlear implantation (3)

Cochlear implants are designed to substitute for the function of the middle ear, cochlear mechanical motion, and sensory cells, transforming sound energy into electrical energy that will initiate impulses in the auditory nerve

Implant systems consist of both consist of both internal and external componentsinternal and external components


Cochlear implantation (4)

The external components (over or next to the ear) include (1) a microphone, which converts sound into an electrical signal, (2) a speech processor, which manipulates and converts the signal into a special code and (3) a transmitter, which sends the coded electrical signal to the internal components

The surgically implanted components include (A) a receiver, which decodes the signal from the speech processor, and (B) an electrode array, which stimulates the cochlea with electrical current

The systems are powered by batteries located in the speech processor


Rehabilitation (1)Rehabilitation is the very important post-surgical stage of

cochlear implantation

It is a complex and long process which essentially depends on individual characteristics of the patient (auditory experience, general abilities and the absence of mental defects)

It is accepted to distinguish between the two groups of patients with cochlear implants :

pre-lingual - the hearing loss occurred before the patient has learned to speak (in general, before the second year of life) and

post-lingual - when the hearing loss occurred in the age of four years or later (after the patient has learned to speak)


Rehabilitation (2)The main task of rehabilitation : for post-lingual patients - the regeneration of the ability to

perceive and to understand spoken language (the forming of connections between the distorted auditory information and previous internal patterns of speech and other sounds)

for pre-lingual patients - the development of the foundations of auditory perception from the beginning (includes the basic elementary operations - detection and discrimination of sounds) and building up the whole system of spoken language

So for all listeners with cochlea implants – a primary rehabilitation problem is the creation or correction of «new» auditory patterns


Rehabilitation and music cochlear implants have been designed primarily to enhance

speech perception many implant recipients anticipate enjoying music following

the implantation in fact, up to 38 per cent of implant recipients report they do

not enjoy listening to music with their device up to 86 per cent of post-lingual recipients report lower

scores of listening habits after implantation musically oriented rehabilitation programs should be used in

order to narrow the gap between pre-surgical expectancies of the implant recipients and their post-surgical experiences


Hypothesis pitch has been reported to be recognized with

more difficulty than rhythm or timbre by implant recipients (because frequency encoding is robust with an implant), therefore temporal and timbral aspects of music are expected to be perceived better than pitch


Method about 150 cochlear implant receivers in St.

Petersburg area by 2005 they are interviewed in order to study their

post-surgical adaptation to listening music interviews are conducted at the Institute of

Otolaryngology in St. Petersburg as a part of general rehabilitation program

selected interviews are videotaped


Training system for rehabilitation program The system has been developed in collaboration between the

Pavlov Institute of Physiology, and the Institute of Otolaryngology in St. Petersburg where the surgery and post-surgical rehabilitation of the patients is carried out

In practice, the system consists of the laptop, two loudspeakers, and a console for patients under school age

The software for the computerized training and rehabilitation system includes standardized available components as well as original modules developed for the tasks to be fulfilled in the framework of the project


Interview Did you listen to speech, music, or noise? If this was music, was it singing or playing an

instrument? If this was singing, was there just one performer or

many of them? Were the singers male or female? If this was playing an instrument, was there just one

instrument or many? String, wind, or percussion? Was this music joyful or sad? Fast or slow? Pleasant

or not? Simple or complicated? Did this music sound in high, medium or low

register?


Choice of music for the interviewFour excerpts from world music, with different sound

characteristics: Japanese bamboo flute shakuhachi: one voice, long

notes, timing plays little role Saami jojk (Mari Boine): female singing, one voice,

heterogeneous rhythm Lithuanian sutartine: polyphonic female singing

(facilitates harmonic dissonances), repetitive rhythm Tuvan overtone singing (xöömij): a low fundamental

of special timbre, with higher overtones made audible one-by-one


Long-term spectra of (1) Japanese bamboo flute shakuhachi (top left), (2) Saami jojk (top right), (3) Lithuanian dissonant polyphony (bottom left), and (4) Tuvan overtone singing (bottom right)

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Excerpts from an interview (1)- a post-lingual patient- has used the implant for

4 years- recognizes Lithuanian

polyphonic and Tuvan overtone singing

- confuses shakuhachi sound with Saami jojk

- claims to prefer the jojk to other excerpts


Excerpts from an interview (2) a post-lingual patient has used the implant for a couple

of weeks describes Tuvan overtone

singing as sound of a Jewish harp

describes shakuhachi sound as singing

confuses Saami jojk with Lithuanian polyphony

noticeable progress during the interview

admits using extramusical features (sound volume) to solve the task


Interview results for 10 CI-recipients (age 10 to 55 years, post-surgical experience from 2 weeks to 4 years)

flute jojk sutartine xöömijmusic 10 10 10 7singing 2 10 10 6female singing 1 7 7 2joyful 0 0 8 1fast 0 0 8 0pleasant 8 8 8 0low pitch 2 3 1 8medium pitch 3 1 1 4high pitch 2 0 6 1


Listening preference score for ten CI-recipients


General conclusion Post-lingual patients with cochlear implants

are strongly motivated to attend music even when its perceived acoustical characteristics only remotely resemble the patterns they are familiar with from the period preceding their hearing loss. This may be explained by an ecologically important function music fulfills in people’s everyday life.


A related study of intonation statements and

questions may be distinguished from each other on the basis of intonation

statements tend to have falling intonation while questions tend to have rising intonation


Thanks to Elvira I. Stoljarova of the Pavlov Institute of

Physiology, St. Petersburg, for video recording of the interviews

Wissenschaftskolleg zu Berlin for providing me with a three-month Mellon scholarship

Documents

PERCEPTION OF MUSIC BY PATIENTS WITH COCHLEAR IMPLANTS Jaan Ross (Tartu and Tallinn) Inna V. Koroleva and Jelena A. Ogorodnikova (St. Petersburg)