The relationship of head and brainstem size to main parameters of ABR in the developmental age and in adults.

In a previous investigation the relationship between head size and main parameters of ABR, i.e. waves absolute latencies and interwave delays, was studied in 55 subjects (1). Significant and positive correlation coefficients were found between I-V I.P.I. and the sum of head circumference, nasion-inion, and intertragal distances in the age range 7 to 11 years only and not in adult age. The purpose of the present study was to verify whether in 11 adults a correlation could be demonstrated between ABR parameters and two axial measures of brainstem length, calculated on MRI views. A positive and significant coefficient was found to exist between these measures and I-V I.P.I. and wave V absolute latency.