difficulty understanding speech in the presence of background noise (cocktail party effect)
sounds or speech sounding dull, muffled or attenuated
need for increased volume on television, radio, music and other audio sourcesHearing loss is sensory, but may have accompanying symptoms:

pain or pressure in the ears
a blocked feelingThere may also be accompanying secondary symptoms:

hyperacusis, heightened sensitivity with accompanying auditory pain to certain intensities and frequencies of sound, sometimes defined as "auditory recruitment"
tinnitus, ringing, buzzing, hissing or other sounds in the ear when no external sound is present
vertigo and disequilibrium
tympanophonia, also known as autophonia, abnormal hearing of ones own voice and respiratory sounds, usually as a result of a patulous (a constantly open) eustachian tube or dehiscent superior semicircular canals
disturbances of facial movement (indicating a possible tumour or stroke) or in persons with Bells palsy

Complications
Hearing loss is associated with Alzheimers disease and dementia. The risk increases with the hearing loss degree. There are several hypotheses including cognitive resources being redistributed to hearing and social isolation from hearing loss having a negative effect. According to preliminary data, hearing aid usage can slow down the decline in cognitive functions.Hearing loss is responsible for causing thalamocortical dysrthymia in the brain which is a cause for several neurological disorders including tinnitus and visual snow syndrome. Cognitive decline
Hearing loss is an increasing concern especially in aging populations. The prevalence of hearing loss increases about two-fold for each decade increase in age after age 40.
When used as a label for the audiological condition, it is written with a lower case d.There also multiple educational institutions for both deaf and Deaf people, that usually use sign language as the main language of instruction. Famous institutions include Gallaudet University and the National Technical Institute for the Deaf in the US, and the National University Corporation of Tsukuba University of Technology in Japan. Research
Stem cell transplant and gene therapy
A 2005 study achieved successful regrowth of cochlea cells in guinea pigs. However, the regrowth of cochlear hair cells does not imply the restoration of hearing sensitivity, as the sensory cells may or may not make connections with neurons that carry the signals from hair cells to the brain. A 2008 study has shown that gene therapy targeting Atoh1 can cause hair cell growth and attract neuronal processes in embryonic mice. Some hope that a similar treatment will one day ameliorate hearing loss in humans.Recent research, reported in 2012 achieved growth of cochlear nerve cells resulting in hearing improvements in gerbils, using stem cells. Also reported in 2013 was regrowth of hair cells in deaf adult mice using a drug intervention resulting in hearing improvement. The Hearing Health Foundation in the US has embarked on a project called the Hearing Restoration Project. Also Action on Hearing Loss in the UK is also aiming to restore hearing.Researchers reported in 2015 that genetically deaf mice which were treated with TMC1 gene therapy recovered some of their hearing.