DC Fitzgerald, AS Mark (Washington Hosp, Ctr., Washington DC)
Sudden Hearing Loss: Frequency of abnormal Findings on Contrast – Enhanced MR studies.
AJNR 19: 1433-1436, 1998.
The utility of contrast enhanced, high resolution MRI in patients with sudden hearing loss (SHL) was investigated. It is important to establish a specific diagnosis in the first two weeks, when treatment is most useful.
Contrast enhanced MR images of the temporal bone, cerebellopontine angle, and brain were obtained in 78 patients with SHL.
38% of the patients had abnormal findings on MR images early in the course of their assessment.
A Pitkarana, I Julkunen (Helsinki Univ; Natl Public Health Inst, Helsinki)
Sudden Deafness: Lack of Evidence for Systemic Viral Infection.
Otolaryngol Head Neck Surg 118:397-399, 1998.
Evidence suggests viral infection as a cause of sudden deafness. Interferons (IFNs) are induced by viral infection – they have relatively short half-lives. Some interferon inducible proteins, such as MxA protein, have longer half-lives and can be used as markers for interferon activation. In this study, IFN and MxA were assayed in blood samples from 20 patients affected with sudden deafness.
Neither IFN nor MxA protein levels were elevated in any of the patients with deafness of unknown cause.
Though the results rule out systemic viral infection as a cause of sudden deafness, they do not exclude a LOCALIZED viral infection as a possible cause.
RJ Stokroos, FWJ Albers, J Schirm (Univ Hosp Groningen, The Netherlands; Regional Public Health Lab, Groningen, The Netherlands).
The Etiology of Idiopathic Sudden Sensorineural Hearing Loss: Experimental Herpes Simplex Virus Infection of the Inner Ear. Am
J Otol 19:447-452, 1998.
Experimental herpes simplex virus type-1 (HSV-1) labyrinthitis provides a useful animal model for studying the pathophysiology of idiopathic sudden sensorineural hearing loss (ISSHL).
The histopathologic characteristics induced by HSV-1 infections were similar to those seen in ISSHL. The striae vascularis had degnerated, the organ of Corti had atrophied, the tectorial membrane had loosened and neural structures showed inflammatory changes.
Though the causative virus of ISSHL has not been identified, the use of viral models in experimental animals may help to identify the virus.
T Lamberg, MT Pitkanen, T Marttila, et al (Toolo Hosp. Helsinki; Helsinki Univ)
Hearing Loss after Continuous or Single-shot Spinal Anesthesia.
Reg Anesth 22: 539-542, 1997.
Transient hearing loss may occur (as high as 93% reported) after spinal anaesthesia that used a 22 gauge needle. This is probably due to decrease in CSF pressure which is transmitted to endocochlear lymph. The intercommunication between perilymph and spinal fluid may occur both at the level of the modiolus and at the level of the cochlear aqueduct.
DD Morrissey, JM Talbot, AJ II Schleuning (Oregon Health Sciences Univ, Portland)
Fibrous Dysplasia of the Temporal Bone: Reversal of Sensorineural Hearing Loss after Decompression of the Internal Auditory
Canal. Laryngoscope 107:1336-1340, 1997.
Fibrous dysplasia affecting the temporal bone is associated with conductive hearing loss resulting from compression of the external auditory canal. The authors have reported one case of bilateral involvement of the temporal bone (rare, since most cases are unilateral).
The literature contains 76 cases of fibrous dysplasia affecting the temporal bone.
In 9 cases, sensorineural hearing loss occurred secondary to fibrous dysplasia – none of these patients recovered their hearing. The case described in the article is the only known case where surgical decompression led to recovery of sensorineural hearing.
WPL Hellier, G Watters, RJ Corbridge, et al (Frimely Park Hosp, Surrey, England; Northampton Gen Hosp, England; Radcliffe Infirmary, Oxford, England)
Grommets and Patient Satisfaction: An Audit.
Ann R Coll Surg Engl 79:428-431, 1997.
Parents of 175 children, 15 years or younger who had had grommets inserted between 3 to 12 months earlier, completed a questionnaire, regarding parents’ or patients’ satisfaction with the results of the procedure.
92% patients noticed improvement in hearing. Reduced frequency of ear infections occurred in 74%. About 70% noticed less time missed from school. 97% of parents were satisfied with the procedure.