High-Resolution Computed Tomographic Evaluation of the Cochlear Capsule in Otosclerosis: Relationship between Densitometry and Sensorineural Hearing Loss

Abstract

Otosclerotic cochlear involvement is a rather frequent disease that has not been clearly understood in terms of diagnosis and management. Objective evaluation methods are needed to confirm the clinical diagnosis, investigate the relationship with hearing impairment, and validate the results of treatment. In this study two ear groups with bone conduction hearing loss (BCHL) were investigated with audiometry and high-resolution computed tomography (HRCT). In the first group (n = 22) the diagnosis of fenestral otosclerosis was confirmed at operation; the second group (n = 9) was composed of ears clinically suspicious for purely cochlear involvement. Additionally, a control group (n = 14) of otologically normal ears was also studied. Foci of demineralization were demonstrated in 58% of the ears in the two groups; the sensorineural hearing loss (SNHL) in those ears was significantly worse than in those with normal radiologic findings. Three methods of HRCT densitometry were used to determine the abnormal regions in the cochlear capsule; the results suggested that hypodense regions were consistent with a greater degree of SNHL, in contrast to the hyperdense ones in ears with better cochlear reserves. Agreement was found between the location of the density change and the frequency topography of the SNHL; densitometric values were correlated with the bone conduction thresholds for certain frequencies. It is concluded that the spongiotic foci are responsible for the SNHL, since there was a correlation between their location and the SNHL frequency. The determination of better hearing in those ears with sclerotic foci supports the hypothesis that the sclerotic phase may not be a healing process following the spongiotic phase, and that it can be the first stage of the disease.

Relationship between CT densitometry with a slice thickness of 0.5 mm and audiometry in otosclerosis

“…Swartz et al [19] have shown a correlation between decalcification of the otic capsule and SNHL at high, middle, and low frequencies, although quantitative evaluation, such as densitometry, was not performed. In other reports using a 1.5-mm slice thickness, it has been shown that the highest correlation is seen in the middle cochlear turn or the basal cochlear turn [18,19]. In the present study, although the highest negative correlation was observed in ROIs 2, 5, and 6, corresponding to the middle turn, no clear correlations were found between the position of decalcification and the hearing loss frequency.…”

“…Although the CT densitometry of fenestral otosclerosis and the correlation between CT densitometry and audiometry have been reported [16][17][18][19][20][21][22], there have been few reports concerning CT densitometry or the cutoff value for the diagnosis of otosclerosis using CT images with a slice thickness of 0.5 mm.…”

Speech Perception after Cochlear Implantation in 53 Patients with Otosclerosis: Multicentre Results

“…In the active phase, socalled osteospongiosis, the normal lamellar bone is resorbed and through a vascular stage is replaced by thick, irregular bone in the normal middle layer of the otic capsule [Guneri et al, 1996]. The subsequent hearing loss can be conductive, which is most commonly caused by stapes fixation due to plaque formation around the oval window, or sensorineural in the case of cochlear involvement.…”

Environmental Exposures to Low Level of Cadmium and Lead and Hearing Impairment in Iraqi Patients

“…This suggestion is supported by many bone disease study that has stated a relationship concerning BMD in cochlear capsule beside sensorineural auditory impairment [41,42], and previous studies about the renal system that indicated an association between decreased glomerular filtration rate and neurosensory hearing impairment [43].…”