Identical twins affected by congenital cytomegalovirus infections showed different audio-vestibular profiles

Abstract

This study explored whether there were long-term hearing and vestibular outcome differences between five pairs of identical twins who had been infected with the congenital cytomegalovirus (CMV) infection before birth. Data were collected from the medical records at the Audiological Clinic, Karolinska University Hospital, Stockholm. The congenital CMV infection resulted in high variations in vestibular and hearing function within, and between, the genetically identical twin pairs. Clinicians need to be aware that treatment and interventions may need to differ substantially when identical twins have hearing issues related to the congenital CMV infection.

Keywords: congenital cytomegalovirus infection; hearing impairment; identical twins; vestibular disorders.

FIGURE 1

Audio‐vestibular testing of Pair 3. In twin 1, an audio‐vestibular failure on the right and a left partial audiovestibular loss, with preserved hearing especially in middle and low frequencies and with reproducible cVEMP (evidenced area). In twin 2, a severe hearing impairment associated with normal canal function on the right, and a left deafness with canal failure. In twin 2, the reproducibility of cVEMP was poor on both sides. The two subjects were tested at the age of 15 months, and twin 2 carried a cochlear implant on the left side. The poor reproducibility of cVEMP may be partially attributed to the use of prudential reduced stimulation levels (mastoid BC 500 Hz, at 119 dB FL), according to the cVEMP infantile protocol in use at our department (Karolinska university hospital). vHIT was conducted with the Synapsys (Marseilles, France) VHIT Ulmer system, and cVEMP was recorded with signal averager Eclipse EP 25 with the VEMP module (Interacoustic A/S, Middelfart, Denmark) and evoked by mastoid BC 500 Hz, 6 ms tone burst stimuli at 119 dB FL under controlled neck muscles activity

FIGURE 2

Audio‐vestibular testing of Case 5. Normal audio‐vestibular function on the right and an isolated vestibular failure on the left in twin 1. CVEMP was depressed on both sides. Twin 2 presented bilateral deafness with preserved canal function bilaterally, but poor CVEMP reproducibility. These two children were tested at the age of 6 and twin 2 carried bilateral cochlear implants. The poor reproducibility of cVEMP may be partially attributed to the use of prudential reduced stimulation levels (mastoid BC 500 Hz, at 119 dB FL), according to the cVEMP infantile protocol in use at our department (Karolinska university hospital). vHIT was conducted with ICS Impulse vHIT Otometrics Natus (Taastrup, Denmark), and cVEMP was recorded with signal averager Eclipse EP 25 with the VEMP module (Interacoustic A/S, Middelfart, Denmark) and evoked by mastoid BC 500 Hz, 6 ms tone burst stimuli at 119 dB FL under controlled neck muscles activity