18 months ago Rosie had to have a benign tumour removed from her ear canal. Unfortunately this left her deaf in that ear, what we didn't realise that she was totally deaf in the other ear and had never realised.
Looking back, she would always jump and bark if a person or dog came up behind her and she was intently sniffing at something. I had always put it down to being startled as she has always been quite a nervous dog. Her nervousness was probably down to them coming up on her deaf side.
Her hearing in general wasn't impaired and could hear the dishwasher door being opened from the garden
She is completely deaf now and in fact is less nervous when out. TBH she's just got on with it and you'd never know. Her eyesight is still good and so I just wave my arms about to "call" her. Fortunately she is food obsessed so doesn't stray far from the biscuits in my pocket.
She is 14 and could possibly have had hearing in only one ear from birth.