Auditory deprivation and recovery in adults with asymmetric sensorineural hearing impairment

The purpose of this investigation was to investigate (1) whether auditory deprivation effects are present in the poorer ears of adults with asymmetric sensorineural hearing impairment and (2) whether, if such effects are present, they can be reversed by amplification. Subjects were 16 males with asymmetric sensorineural hearing impairment, 8 of whom had never been aided, 6 of whom were aided monaurally at the initial test, and 2 of whom were unaided at the initial test but aided monaurally later on. Data were obtained from a retrospective review of records. The initial and retest (2-13 years post initial test) suprathreshold speech-recognition scores for 50-word, taped lists of the CID W-22 PB words were analyzed. The results revealed a significant difference between the initial and retest mean suprathreshold speech-recognition scores for the poorer ears of the unaided subjects. The results also revealed no significant change from the initial test to retest in six of the aided ears and significant improvement from the initial test to retest in the two of the aided ears. The findings are discussed with reference to the theory of auditory deprivation and recovery from auditory deprivation by amplification.     

Effects of prolonged lack of amplification on speech-recognition performance: preliminary findings

The purposes of this investigation were two-fold: 1) to prospectively investigate the effect of prolonged lack of binaural amplification in the unaided ears of adults with bilaterally symmetrical sensorineural hearing impairment (BSSHI) fitted monaurally; and, 2) to prospectively investigate the effects of amplification on speech-recognition performance in the aided ears of monaurally and binaurally fitted subjects. Subjects consisted of 19 monaurally aided adults, 28 binaurally aided adults, and 19 control adults. Both ears of the experimental subjects (binaurally and monaurally aided adults) had BSSHI. The speech measures included the W-22 CID suprathreshold speech-recognition test, nonsense syllable test, and speech-perception-in-noise test. Initial testing was done between 6 and 12 weeks following hearing-aid fitting. Retests were performed approximately 1 year following the initial test. The results revealed that the mean aided minus unaided ear score for the nonsense syllable and W-22 tests increased significantly from the initial test to retest, reflecting a slight improvement in speech performance in the aided ear and a slightly greater decrement in the unaided ear. The findings were interpreted with respect to the theories of auditory deprivation and acclimatization.     

Chromium–protein complexation studies by adsorptive cathodic stripping voltammetry and MALDI-TOF–MS

A methodology using stripping voltammetry has been elaborated to enable sensitive and reliable protein–chromium complexation measurements. Disturbing effects caused by adsorption of proteins on the mercury electrode were addressed. At low concentrations of proteins (<60–85 nM), chromium–protein complexation measurements were possible. Chromium(VI) complexation was quantitatively determined using differently sized, charged, and structured proteins: serum albumin (human and bovine), lysozyme, and mucin. Generated results showed a strong relation between complexation and protein size, concentration, and the number of amino acids per protein mass. Complexation increased nonlinearly with increasing protein concentrations. The nature of this complexation was based on weak interactions judged from combined results with MALDI-TOF–MS and adsorptive cathodic stripping voltammetry.