Table 3

Suggested protocol for the aetiological investigation of childhood deafness

Audiology
• Age appropriate, reliable audiological assessment, including tympanometry
→child/proband
→parents & sibs (if any clinical suspicion of hearing loss)
Urine analysis
• CMV (first 2–3 weeks only)
• Glucose
• Microscopy
• Organic and amino acids
Blood
• Viral serology
 ⇒rubella (first six months only)
 ⇒toxoplasma
 ⇒syphilis
• DNA storage
• Cytogenetic analysis
• T4 & TSH
ECG
Ophthalmological assessment
• ERG
CT/MRI
Vestibular function testing
Perchlorate discharge test
Renal ultrasound scan