Head bumps and guilt....

The news that Lily's hearing loss is due to a genetic reason has really been a big surprise. Chris and I have had very different reactions. He has been relieved to find out what caused her loss, since 50% of cases of childhood deafness are never explained. I have had a strange (and admittedly illogical) sense of guilt about it that is hard to articulate- maybe just that some defective part of me caused her to be deaf. And equally illogical is my guilt that I was not able to prevent her from bumping her head as often as she did (and continues to do) in her everyday activities. The enlarged vestibular aqueducts (EVA) that cause hearing loss appear to be worsened in some cases by head trauma, sometimes even minor trauma. I cannot even tell you how many times Lily has clunked her head- I often threatened to get her a helmet when she was a new walker.

Another important characteristic is that, most people with LVAS experience sudden hearing loss following a minor head injury or other activity which causes increased intra-cranial pressure (increased cerebrospinal fluid pressure). In one study the figure was 85.7% while another study reported 61%. A mild bump on the head, tripping or falling down or even jumping can jar the head enough to result in more hearing loss. Also, sudden hearing loss can follow a minor illness such as a common cold, strenuous exercise or a sudden change in barometric pressure.

In one study of 12 children with LVAS, five had sudden hearing losses. Three of the episodes followed relatively minor head injuries. The fourth occurred while forcefully playing a trumpet, and the fifth occurred immediately after an airplane flight.

In another case, a six-year-old child ran into a goal post while playing soccer and hit his head on the left side. This resulted in sudden hearing loss in the left ear. Three years later, after mild head injury while on the school playground, the child again reported an immediate hearing loss, this time in the right ear. An audiogram done that same day revealed severe to profound hearing loss in the right ear and profound hearing loss in the left. A CT scan revealed bilateral large vestibular aqueducts with no other inner ear abnormalities. Over the next month, hearing fluctuated between moderate and severe.

After episodes of sudden hearing loss, hearing may recover to the previous level, or much more commonly, it may recover partially to a new "normal." One girl with LVAS had characteristic attacks of sudden hearing loss following minor head trauma, common colds or exercise. Her high frequency hearing is now almost non-existent but her low-frequency hearing tends to recover shortly after each episode.

Hearing loss in LVAS generally follows a step-wise pattern. Each incident causes the hearing to drop another step. The hearing loss will follow one of two patterns. One is a gradual progressive stepwise hearing loss, but with fluctuations. The other is sudden bouts of hearing loss of at least 15 dB that may fluctuate to profound levels following minor head injuries or fluctuations in the pressure of cerebrospinal fluid (CSF). Usually these acute drops in hearing do not recover to previous levels. The end of this downward progression typically is profound hearing loss.