Better in Noise, Worse in Noise!

Hearing loss has been reported since early documentation of medical knowledge, and several categorization exist based on etiology, severity, laterality, pathology, degree of handicap, and time of onset. 

Of interest to hearing care physician is the phenomena of hearing in noise, of which there were 2 types:

1. Hard-of-hearing patients hear conversations better in noise

2. Hard-of-hearing patients hear conversations worse in noise

While the latter is seen commonly with one ear hearing situation (unilateral hearing loss) and can be easily explained based on our understanding of the auditory pathway, the first phenomenon was not easy to explain (ever heard or read about the legend of the deaf woman who can only hear when someone is beating the drum?). 

The first phenomenon was first described by Willis in 1672, and together With the observation that such hard-of-hearing patients also perceive constant signals better in noise, is referred to as paracusis willisii. The explanation for the phenomenon of paracusis willisii was to occupy physicians for another 3 centuries until Politzer  (1901), Lombard (1911) and Jenkins (1938), Lowenberg and Urbantschitsch, Siebenmann and Von Tröltsch  made interesting attempts. 

Various explanations put forward for this phenomena include:

1. General vibration of the loose ossicular chain (Politzer)

2. Production of increased irritability of the acoustic nerve (Jenkins, Lowenberg and Urbantschitsch)

3. Background noise is low pitched, not well heard by patient, while normal observer in conversation with patient raises his voice (Lombard, Sibenmann & Von Tröltsch). 

Variations of Paracusis willisii was reported by Hastings & Scarf in 1928 (relative paracusis, absolute paracusis) and this interesting observation continue to form important diagnostic indicator for otosclerosis. 

References:

1. Proc R Soc Med. 1928 February; 21(4):611-616

2. Laryngoscope 1952 vol. 62(7) pp. 678-703