All Phenotypes Eps8l2<tm1Wma> MGI Mouse

abnormal cochlear hair cell morphology ( J:200669 )

• at P240 cuticular plate thickness is reduced and in some cases the cuticular hair plate is partially fragmented in hair cells

abnormal cochlear hair cell stereociliary bundle morphology ( J:200669 )

• at 1 month of age a few abnormally long stereocilia are visible in the middle row and some stereocilia are shorter or missing

• at 3 and 8 months of age, progressive deterioration of bundles with loss of the staircase structure is seen in both the inner and outer hair cells

• at 3 and 8 months of age, the most obvious abnormalities include larger number of shorter or missing stereocilia and a shallower hair bundle staircase architecture that is more pronounced in inner hair cells

• defects are more pronounced in higher frequency regions of the cochlea

decreased inner hair cell stereocilia number ( J:200669 )

• at P90 in apical IHCs

• at P90 tall stereocilia are shorter and fewer than in controls and intermediate stereocilia are narrower and tend to be irregular in shape

• abnormalities are accentuated at P240

short cochlear hair cell stereocilia ( J:200669 )

• at 1 month of age some stereocilia are shorter or missing

• at P90 tall stereocilia are shorter and fewer than in controls

• at 3 and 8 months of age a larger number of shorter or missing stereocilia are seen

abnormal hearing electrophysiology ( J:200669 )

abnormal auditory brainstem response ( J:200669 )

• reduced ABR-wave amplitudes for all waves in the average ABR and latencies for all peaks are prolonged at 2 months of age

increased or absent threshold for auditory brainstem response ( J:200669 )

• increased thresholds for click, noise burst, and pure tone stimuli above 4 kHz at 2 months of age

• thresholds are further increased at 5 and 7 months of age and are absent for pure tone stimuli at frequencies greater than 22 kHz at 5 months of age

abnormal auditory summating potential ( J:200669 )

• summating potentials thresholds are elevated at all frequencies tested

decreased cochlear nerve compound action potential ( J:200669 )

• thresholds for click evoked CAPS are about 32 dB higher compared to wild-type littermates

• for pure tone stimulation thresholds for tones above 4kHz are increased and no responses are seen above 8 kHz

abnormal distortion product otoacoustic emission ( J:200669 )

• increased thresholds at 22.6 and 32 kHz stimulus frequencies at 2 months of age

• amplitudes are lower at nearly all stimulus levels and thresholds are increased for stimulus frequencies at and above 11.3 kHz at 5 months of age

impaired hearing ( J:200669 )

• progressive hearing loss

abnormal vestibular system physiology ( J:200669 )

• in vestibular-evoked potential waveforms, P1 latencies are prolonged