**Author details**

Similarly, the relationship with hearing loss is not clear. Nevertheless, a prompt recognition of the hearing difficulties, which can be among the first manifestations of the disease, might

Inner ear and retrocochlear involvement in MPS patients is more frequent than initially suspected. Observation of seromucinous effusion in the middle ear does not exclude the presence of a sensorineural hearing loss. An otological and audiological investigation should be warranted to all defined or suspected MPS patients. Inner ear or central auditory lesions detected by the audiological tests should be further investigated by specific MR imaging processing

Early identification of hearing loss not only enables proper acoustic rehabilitation, but also

The authors wish to thank Dr. Paolo Remida, M.D. for the Neuroradiological workup; Prof. Werner Garavello, M.D. for clinical advice; and Dr. Serena Costanzo, Ph.D., for audiological

The authors report no financial interest in the subject matter, no actual/potential conflict of

ABR auditory brainstem responses (acoustically evoked potentials)

COR conditioned oriented responses (test of hearing for babies)

AC air conduction (pure tone audiometry)

BC bone conduction (pure tone audiometry)

CPAP continuous positive airways pressure

supports the diagnosis of MPS, especially in its milder forms and/or initial stages.

help assessing an earlier diagnosis and, therefore, provide a timely treatment.

**5. Conclusions**

66 An Excursus into Hearing Loss

algorithms.

**Acknowledgements**

**Conflicts of interest**

interest.

**Abbreviations**

avg. average

CNS central nervous system

testing. No funding sources supported research.

Diego Zanetti<sup>1</sup> \*, Margherita Vezzani2,3, Federica Di Berardino<sup>1</sup> , Serena Gasperini<sup>4</sup> and Rossella Parini4

\*Address all correspondence to: diego.zanetti.bs@gmail.com

1 Audiology Unit, Department of Community Health and Clinical Sciences, Università degli Studi di Milano; Fondazione IRCCS Cà Granda, Ospedale Maggiore Policlinico Milano, Italy

2 Otorhinolaryngology Department, University of Milano-Bicocca, San Gerardo Hospital, Monza, Italy

3 Pediatric Otorhinolaryngology Department, Children's Hospital, Cincinnati, USA

4 Rare Metabolic Diseases Unit, Department of Pediatrics, University of Milano-Bicocca, San Gerardo Hospital, Monza, Italy
