Table 1.
Summary appraisal of the case-control included studies.
| Study Design | Population Studied (n) |
Case Group Definition | Control Group Definition | Hearing results | Diagnosis of cytomegalovirus (CMV) infection | Relationship CMV- Sensorineural Hearing Loss (SNHL) | |||
|---|---|---|---|---|---|---|---|---|---|
| Pure Tone Audiometry | Neurophysiological Testing | Ascertainment Method | Determinant | ||||||
| Jim et al., 2015 [22] |
Prospective case-control | Children <35 weeks (55) | Postnatal CMV infection through breast feeding (14) | Negative CMV infection (41) | Two infants with mild peripheral hearing impairment in both groups |
No permanent delayed speech | Polymerase Chain Reaction (PCR) CMV isolation enzyme-linked immunosorbent assay (ELISA) |
PCR-positive viral DNA in urine Culture positive urine (viruria) Antiviral IgM (serum) |
None of the infants had CMV-related death or permanent SNHL |
| Turner et al., 2013 [23] |
Retrospective case-control (from 1993 to 2008) | Infants with birth weights <1500 g (176) |
Acquired CMV infection (16) | Negative CMV infection (160) | Suspected SNHL in 20% of infants with acquired CMV and 14% controls |
Acquired CMV was not associated with neurologic sequelae | CMV isolation | Culture positive urine | Congenital CMV in infants is associated with high rates of neurologic injury and hearing loss comparing with acquired CMV infants |
| Kikidis et al., 2010 [24] |
Prospective case-control | Adults patients with sudden SNHL (84) | CMV, herpes simplex virus, toxoplasma and Epstein-Barr infection (8) |
Negative virus/toxoplasma infection (76) | Hearing level was 86.5 dB HL in the case group and 60.7 dB HL in the control group. |
ELISA | Antiviral IgM (serum) | Recent subclinical viral or toxoplasmosis infections may be involved in the pathogenesis of sudden SNHL (in approx. 10% of cases), suggesting that sudden SNHL is not a single disease | |
| Verbeeck et al., 2008 [25] |
Retrospective case-control (from 2002 to 2004) | Babies born between April 2002 and April 2004 (526) |
194 babies with indicative hearing impairment (22 positive CMV; 172 negative CMV) |
332 matched controls without hearing impairment (15 positive CMV; 317 negative CMV) |
Hearing impairment at birth was confirmed by an audiological center in 136 out of the 526 tested babies while 390 tested babies proved to have normal hearing. | None of the children had developed delayed-onset hearing loss at the end of the study |
PCR CMV isolation |
PCR-positive viral DNA in urine Culture positive urine | Significantly more babies with confirmed hearing impairment were CMV positive after birth Babies with CMV viral loads above 4.5 log copies/mL urine seem to be 1.4 times more likely to have confirmed hearing impairment. |
| Samileh et al., 2008 [26] |
Case-control study (from 2002–2003) | Children <14 years (158) |
Children with SNHL (95) Acute infection (CMV-IgM) in 33/95, previous immunity (IgG) in 69/95 |
Children without SNHL (63) Acute infection (CMV-IgM) in 2/57, previous immunity (CMV-IgG) in 54/57 |
Severity of SNHL in cases included: 80% profound >95 db; 15% moderate; 5% mild. Unilateral SNHL 22% (20/95); bilateral SNHL 78% (75/95). |
ELISA | Antiviral IgG and IgM (serum) | CMV is one of the most common infectious agents in SNHL children compared to the healthy children. Probably both congenital and acquired CMV can induce progressive hearing loss. |
|
| Johnson et al., 1986 [27] |
Prospective case-control | Infants (80) | Premature or sick term infants with perinatally acquired CMV (40) |
Matched control subjects (40) |
One case group subject had a bilateral SNHL> 4000 Hz. Four control subjects had SNHL, 3 requiring binaural hearing aids. | There were 12 transient conductive hearing losses due to serous or suppurative otitis media. Five of these losses were in the case group and seven were in the control group |
CMV isolation | Culture positive Urine and/or saliva |
Perinatally acquired CMV infection is not associated with significant SNHL in premature or full term infants through age 3. |
| Paryani et al., 1985 [28] |
Prospective case-control | Infants (84) | Premature or sick term infants with perinatally acquired CMV (42) | Matched control subjects (42) |
SNHL in 4 of 42 CMV infected patients (all mild-moderate) and in 2 of 42 controls (one severe) | All of the CMV infected patients had SNHL >4000 Hz, and hearing aids were not required. | CMV isolation | Culture positive urine and saliva | Acquired CMV infections are not associated with a significant increase in SNHL |
| Paradowska et al., 2013 [29] |
Prospective case-control | Children (93) Adults (55) |
Postnatal CMV infection + SNHL | CMV infected adults | Hearing loss in 10 children (11%) | Nested PCR (nPCR) | Viral DNA from peripheral blood, urine, and/or cerebrospinal fluid samples | No association was found | |
| Wilson, 1986 [30] |
Prospective case-control | Adults and children (217) | SNHL | Healthy patients | Profound and mild, mid-frequency hearing losses | Complement fixation assay (CFA) | Antiviral IgG and IgM (serum) | No differences were found between the effects of herpes virus infection upon the degree of hearing loss in patients with or without herpes infection | |