The quadriceps is the knee extensor, but the rectus femoris additionally flexes the hip joint, and articular muscle of the knee protects the articular capsule of the knee joint from being nipped during extension. The sartorius runs superficially and obliquely down on the anterior side of the thigh, from the anterior superior iliac spine to the pes anserinus on the medial side of the knee, from where it is further extended into the crural fascia. The sartorius acts as a flexor on both the hip and knee, but, due to its oblique course, also contributes to medial rotation of the leg as one of the pes anserinus muscles (with the knee flexed), and to lateral rotation of the hip joint.There are four posterior thigh muscles. The biceps femoris has two heads: The long head has its origin on the ischial tuberosity together with the semitendinosus and acts on two joints. The short head originates from the middle third of the linea aspera on the shaft of the femur and the lateral intermuscular septum of thigh, and acts on only one joint. These two heads unite to form the biceps which inserts on the head of the fibula. The biceps flexes the knee joint and rotates the flexed leg laterally—it is the only lateral rotator of the knee and thus has to oppose all medial rotator. Additionally, the long head extends the hip joint.
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.