Because there is a decline in sound stimuli and sensory deprivation, hearing loss can lead to structural and functional changes in the brain. These structural and functional changes can affect the brain's capacity to process and perceive sounds and may contribute to cognitive decline.
The brain is forced to compensate for these losses by activating alternative circuits. It enlists accessory neuron networks and that means increased cognitive effort is needed to weed out irrelevant sounds, like background noise, and more concentration is needed for hearing.
A high cognitive effort reduces the amount of brain resources available to process everything else. There's less of a cognitive reserve to tap into. So, things like concentration, memory and planning capacity may be affected. It's easier to get distracted. And constantly decoding and processing sounds can take up a lot of mental resources which can be tiring, eventually leading to potential withdrawal from social interactions.