A new method for Partial Deafness treatment ( PDT)

1    Partial Deafness

In recent years, there has been a change of attitude towards cochlear implant candidacy criteria, resulting from the development of implant technology and growing expertise in surgery and rehabilitation. Today, not only individuals with the bilateral profound hearing loss are considered likely to receive a cochlear implant; also these with considerable residual hearing, or even normal hearing at low frequencies up to 1,5 kHz, are considered as candidates for cochlear implantation (Skarzynski et al., 2010). There is a large group of patients whose hearing impairment is characterized by normal or slightly elevated thresholds in the low-frequency band with nearly total deafness in higher frequencies. We proposed to describe this type of hearing impairment as partial deafness. Patients with good hearing only in the low frequencies are able to detect all the vowels, but probably few, if any, consonants. Low frequency perception can foster speech reading, speech production, and environmental sound awareness can contribute to the recognition of intended emotions. Notwithstanding, such hearing still does not allow patients the ability to communicate efficiently in everyday life, particularly in noisy listening situations. Often these patients remain beyond the scope of effective treatment with hearing aids only, since amplification at frequencies above the region of substantial residual hearing provides little or no benefit for individuals with partial deafness.

2    Cochlear Implantation in the partially deafened case

In 2002 our centre decided to implant a partially deafened young woman [Skarżyński, Lorens, Piotrowska; 2003]. The patient’s left ear was implanted with a Med-El Combi 40+ system, using the standard electrode array. To avoid loss of low-frequency hearing, a partial electrode insertion was performed, with an approach to the scala tympani directly through the round-window membrane. The approximated depth of insertion was 20 mm. Eight of the 12 electric contacts were inserted. The low frequency hearing was preserved to the large extend as proved by audiometric and ABR evaluation. The audiometric thresholds measured at 125 Hz and 250 Hz were the same as those measured preoperatively. After a short period following activation of the cochlear implant, a quite large and highly significant improvement in the recognition of monosyllabic words was observed. 
Results from the first case supported further applications of cochlear implants for people with partial deafness [Skarżyński, Lorens, Piotrowska; 2003]. 

3    Partial Deafness Cochlear Implantation (PDCI)

Obtained results from the first partially deafened case were considered to be the first step towards the application of a partial deafness cochlear implantation (PDCI). To implement the method, a 3-step procedure was proposed, with pre-, intra- and post-operative parts [Skarżyński, Lorens, Piotrowska; 2003].
PDCI essentially involves 3 challenging aspects. 1) Careful selection of the right candidates most likely to gain substantial benefit from the procedure; 2) Surgical techniques allowing hearing preservation; and 3) transferring the maximum amount of sound information to the patient using an optimized configuration of electrical pulses to the electrodes combined with acoustic information.
The preoperative part of PDCI method includes clinical and audiological assessment to confirm fulfillment of qualification criteria, i.e., thresholds of 55 dB HL at 125, 250 and 500 Hz, and thresholds of 70 dB HL or higher at all higher audiometric frequencies. The subject should obtain limited benefit from the most-optimally fitted hearing amplification, with monosyllable scores in quiet of  55% correct or lower in both ears in the best-aided condition, at 60 dB SPL [Skarżyński, Lorens, Piotrowska; 2003].

The surgical procedure of PDCI proposed by Skarzynski consists of the following steps [Skarzynski et al. 2003, 2007a]:

1.    Antrotomy
2.    Posterior tympanotomy to allow for visualisation of the round window niche
3.    Puncture the round window membrane
4.    Approach the scala tympani directly through the round window membrane (with partial insertion of the electrode array)
5.    Electrode fixation in the round window niche with fibrin glue (membrane must be partially uncovered to preserve its mobility)
6.    Fixation of the device in the well created in the temporal bone

The postoperative part of PDCI method includes audiological assessment of preserved  hearing sensitivity at low frequencies and cochlear implant system fitting, with the latter focused on selection of appropriate parameters of electrical stimulation. [Skarżyński, Lorens, Piotrowska; 2003]. We demonstrated that PDCI subjects were able to use their natural low-frequency hearing without amplification together with their cochlear implant (CI) to obtain outstanding results in speech tests. As there is only partial insertion of the electrode, careful consideration of programming the device is required. Only those electrodes inserted in the cochlea are activated and this is determined based on telemetry and reported hearing sensation. Frequency of electrodes is determined by the audiogram. The aim is to programm the cochlear implant without any overlap with acoustic perception, so as to not interfere with this perception. This is usually between 500Hz and 1000Hz. Electrode frequency modification can be adjusted on the cochlear implant fitting software [Lorens et al., 2008].

Encouraged by outstanding results achieved by application of electric and acoustic stimulation in adults the decision was made to perform partial deafness cochlear implantation in children in 2004 (Skarzynski et al. 2007). Our pediatric study results showed that hearing could be preserved partially in all cases. Speech perception tests showed improvement in quiet and noise over time. We demonstrated that children with partial deafness perform better than their pre-operative hearing aid conditions, even in instances where hearing could not be preserved completely.

4.    Partial Deafness Treatment

The criteria for application of acoustic and electric amplification provided by the range of hearing aids, middle ear implants, and cochlear implants may complement one another.
The classification of partial deafness treatment (PDT) was first suggested by Skarzynski et al. 2010. The model is important for evaluating the post-implantation performance in homogeneous groups of patients with various levels of preoperative hearing. Results obtained in distinct groups of patients by authors using various assessment methods can provide valuable data for further widening PDT selection criteria and helping to establish it as a common intervention. All these advancements have resulted in the development and more widespread use of new technologies in postoperative care such as telemedical networks and other health services.


Lorens A, Geremek A, Walkowiak A, Skarżyński H: Residual acoustic hearing in the ear before and after cochlear implantation; in Jahnke K, Fischer M, editors. 4th European Congress of Oto-Rhino-Laryngology Head and Neck Surgery. Bologna, Monduzzi, 2000; 1:135-138

Lorens A, Polak M, Piotrowska A, Skarzynski H. Outcomes of Treatment of Partial Deafness With Cochlear Implantation: A DUET Study. Laryngoscope. 2008

Lorens A, Zgoda M, Skarzynski H. A new audio processor for combined electric and acoustic stimulation for the treatment of partial deafness. Acta Otolaryngol. 2012 Jul;132(7):739-50.

Skarżyński H, Lorens A, D’Haese P et al.: Preservation of residual hearing in children and post-lingually deafened adults after cochlear implantation: An initial study. ORL J. Otorhinolaryngol. Relat. Spec., 2002; 64(4):247-53

Skarzynski H, Lorens A, Piotrowska A: A new method of partial deafness treatment. Med Sci Monit. 2003;9(4):CS20-24.

Skarzynski H, Lorens A, Piotrowska A, Anderson I: Partial Deafness Cochlear Implantation Provides Benefit to a New Population of Individuals with Hearing Loss. Acta OtoLaryngol. 2006;126:934-940.

Skarzynski H, Lorens A, Piotrowska A, Anderson I: Preservation of low frequency hearing in partial deafness cochlear implantation (PDCI) using the round window surgical approach. Acta OtoLaryngol. 2007;127:41-48.

Skarzynski H, Lorens A, Piotrowska A, Anderson I: Partial deafness cochlear implantation in children. J Pediatr Otorhinolaryngol. 2007 Sep;71(9):1407-13.

Skarzynski H, Lorens A, Piotrowska A, Skarzynski PH: Hearing preservation in partial deafness treatment. Med Sci Monit, 2010; 16(11)

Skarzynski H, Lorens A: Partial deafness treatment. Cochlear Implants Int, 2010; 11

Skarzynski H, Podskarbi-Fayette R: A new cochlear implant electrode design for preservation of residual hearing: a temporal bone study. Acta Otolaryngol, 2010; 130: 435–42

Skarzynski H, Lorens A, Matusiak M et al: Partial deafness treatment with the Nucleus Straight Research Array Cochlear Implant. Audiol Neurootol, 2012; 17: 82–91

Skarzynski H, Lorens A, Zgoda M et al: Atraumatic round window deep insertion of cochlear electrodes. Acta Otolaryngol, 2011; 131: 740–49

Skarzynski H, Lorens A, Matusiak M, Porowski M, Skarzynski PH, James CJ. Partial deafness treatment with the nucleus straight research array cochlear implant. Audiol Neurootol. 2012;17(2):82-91.

Skarzynski H, van de Heyning P, Agrawal S, Arauz SL, Atlas M, Baumgartner W, Caversaccio M, de Bodt M, Gavilan J, Godey B, Green K, Gstoettner W, Hagen R, Han D, Kameswaran M, Karltorp E, Kompis M, Kuzovkov V, Lassaletta L, Levevre F, Li Y, Manikoth M, Martin J, Mlynski R, Mueller J, O'Driscoll M, Parnes L, Prentiss S, Pulibalathingal S, Raine CH, Rajan G, Rajeswaran R, Rivas JA, Rivas A, Skarzynski PH, Sprinzl G, Staecker H, Stephan K, Usami S, Yanov Y, Zernotti ME, Zimmermann K, Lorens A, Mertens G. Towards a consensus on a hearing preservation classification system. Acta Otolaryngol Suppl. 2013 Dec;(564):3-13

Skarzynski H, Olszewski L, Skarzynski PH, Lorens A, Piotrowska A, Porowski M, Mrowka M, Pilka A. Direct round window stimulation with the Med-El Vibrant Soundbridge: 5 years of experience using a technique without interposed fascia.Eur Arch Otorhinolaryngol. 2013 Mar 20.

Skarzynski H, Lorens A, Matusiak M, Porowski M, Skarzynski PH, James CJ. Cochlear Implantation With the Nucleus Slim Straight Electrode in Subjects With Residual Low-Frequency Hearing. Ear Hear. 2014 Jan 16.