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Otolaryngology - Head & Neck Surgery
Hospital  >  Departments  >  Otolaryngology - Head & Neck Surgery  >  Patient Information  >  Interventions offered  >  Single-Sided Deafness

Single sided deafness

Single-sided deafness (SSD) is also known as profound unilateral hearing loss. It is a type of hearing impairment that occurs when one ear has no functional hearing ability.

Individuals with SSD have difficulty:

  • hearing conversations on their impaired side
  • understanding speech in the presence of background noise
  • localizing sound (determining the direction, distance and movement of sound)

Treatment options

CROS hearing aids

A CROS (Contralateral Routing Of Sound) hearing aid transmits sound from the poorer ear to the better ear. A microphone/transmitter is placed behind or inside the poorer ear, where it picks up sound and transmits it wirelessly to an amplifying system on or in the normal hearing ear. Hearing in the good ear is preserved and remains completely unaffected.


  • non-surgical
  • no long-term complications
  • least expensive option (systems starting at $2000)
  • partial ADP coverage


  • sound quality is not as good as the other alternatives
  • must wear 2 devices (one in each ear)


The Med-El BoneBridge is another type of bone-anchored auditory processing system. It is a semi-implantable hearing system, where the implant is positioned completely under the skin. The implant receives signals from an external audio processor worn under the hair.


  • sound quality may be as good as BAHA without feedback
  • internal component is concealed
  • hardware is implanted under the skin to avoid long term wound care
  • good cosmetic appearance
  • only a single device is worn
  • sophisticated internal implant (5-year warranty)
  • cost of the implantable portion is supported by OHIP


  • cost
  • surgery and related complications may ensue. For example, infection, implant failure, extrusion

Learn more about bonebridge »

Bone anchored hearing aid (BAHA)

Bone anchored hearing aid (BAHA) uses a surgically implanted titanium element to transmit sound to the inner ear via bone conduction. This bypasses the external auditory canal and middle ear

How it works

A sound processor picks up sound vibrations; a connecting abutment transfers sound into mechanical vibrations from the BAHA device to the implant; a small titanium implant – placed in the bone behind the ear – fuses with the living bone; this implant transfers the sound vibrations, via the skull, directly to the functioning cochlea.


  • excellent coupling to the skull with very good sound quality (the best among all options)
  • only one device must be worn
  • carrying cost of the BAHA is partially offset by OHIP


  • cost
  • surgery and related complications may ensue
  • ongoing care must be performed because of the titanium screw
  • poor cosmetic appearance
  • only replacement processor partially funded by ADP

Learn more about BAHA »

Location and contact

Department of Otolaryngology

Sunnybrook Health Sciences Centre
2075 Bayview Avenue,
M-wing, 1st floor, room M1 102
Toronto, ON M4N 3M5

Phone numbers »

Otolaryngology Clinic:


Hearing Aid:

Cochlear Implant:

Fax »


Hours »

Monday - Friday,
8:30 a.m. – 4:30 p.m.

Referral forms »