Egisto Molini, Ruggero Lapenna*, Laura Cipriani, Maria Rita Del Zompo, Giorgia Giommetti and Giampietro Ricci
Section of Otolaryngology-Head and Neck Surgery, Department of Surgical and Biomedical Sciences, University of Perugia, Perugia, Italy
Received: 25 May, 2017; Accepted: 14 July, 2017; Published: 20 July, 2017
Ruggero Lapenna, Otorhinolaryngology Clinic, S.M. della Misericordia Hospital, Via G. Dottori 1, S. Andrea delle Fratte, 06100, Perugia (PG), Italy; E-mail:
Molini E, Lapenna R, Cipriani L, Del Zompo MR, Giommetti G, et al. (2017) Disturbed auditory perceptions: An Update. Arch Otolaryngol Rhinol 3(3): 071-077. DOI: 10.17352/2455-1759.000050
© 2017 Lapenna R, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Tonsillectomy; Magnification devices; Microscope; Magnifying glasses; Ergonomics; Heart rate; Heart rate variability, Effort to engage; Situation awareness
The search for tinnitus mechanisms is a speculative endeavour; a broad number of mechanisms may cause the tinnitus symptom and numerous tinnitus models have been proposed in recent years. There is no objective methods for detecting or evaluating the severity of tinnitus and severe tinnitus is usually defined as a tinnitus that interferes with sleep, work and social life. Patients, who exhibit a strong emotional reaction to tinnitus, a high level of anxiety, and psychosomatic problems, indicate that the limbic and autonomic nervous systems are crucial in clinically relevant tinnitus cases. Tinnitus is only one of the possible clinical aspects concerning disturbed auditory perceptions. The objective of this review was to organize all described disturbed auditory perceptions, with particular reference to the definition and the pathogenesis of a chronic bothersome tinnitus.
Definitions and classification
Non-pulsatile tinnitus , is an auditory perception that occurs in the absence of any external stimulus , Namely it is the conscious perception of an unorganized acoustic impressions of various kinds , heard in the absence of external or internal physical sound sources . From ecological point of view, we can consider tinnitus as the perception of an auditory object in the absence of an acoustic event: true sounds have an identiﬁable physical source, while tinnitus does not .
Sound perceived from physical sources internal to the body are “true sounds”, such as blood flow, that could be a referred to stenosis in the carotid or vertebrobasilar arteries, and abnormal muscular contraction of the nasopharynx or middle ear, as can occur in palatal myoclonus. They are called “objective tinnitus” because they are generated within the body, transmitted to the ear and generally they audible to the examiner . Somatic tinnitus or somatosound instead not always is detectable by the examiner and in this sense differ from an objective tinnitus .
Pulsatile tinnitus is an example of somatosound generated by an acoustic source from the body described as having a rhythm synchronous with the heartbeat . Known causes of pulsatile tinnitus are: high cardiac output states (anemia, hyperthyroidism); raised intracranial pressure (pseudotumor cerebri, brain tumor), vascular anomalies (dural arteriovenous malformations, dehiscent jugular bulb, sigmoid sinus diverticulum, emissary vein, persistent stapedial artery, carotid-cavernous fistula, aberrant internal carotid artery, carotid artery dissection, stenosis, or fibromuscular dysplasia); increased vascularity of the middle ear and temporal bone (e.g., glomus jugulare tumor, Paget's disease, otosclerosis); superior semicircular canal dehiscence; vascular compression of the auditory nerve.  Pulsatile tinnitus could also result from the blowing flow of the spiral capillary in the basilar membrane .
Somatic tinnitus may also have a modulation of its pitch and loudness by a somatic stimulation , such as voluntary or external manipulations of the jaw, movements of the eyes, or pressure applied to head and neck regions [11 12]. Somatic tinnitus is associated with upper cranio-cervical imbalances , and with mandibular disorders such as temporo-mandibular joint dysfunction [14,15].
The perception of sounds in organized form, such as music or speech in the absence of physical sound sources, is a phantom phenomenon called acoustic hallucination that particularly occurs in patients with schizophrenia or after consumption of hallucinogenic substances . Acoustic hallucinations have been described also in conjunction with various diseases, injury, trauma, bereavement, sensory deprivation, religious experiences, near-death experiences, drugs and in people born profoundly deaf [16,17]. Musical hallucinations tend to occur in people with advanced age and with marked hearing loss without mental illnesses.
Auditory imagery is a normal phenomenon that occurs for all people. It generally refers to perceptions of voices without understandable speech, music or other auditory perceptions in the absence of an appropriate stimulation . It is a central type of tinnitus involving reverberator activity within neural loops at a high level of processing in the auditory cortex [19,20].
Summarizing, the origin of tinnitus can be within the auditory nervous system, in case of neurophysiologic or sensorineural tinnitus, or outside the auditory nervous system, in case of somatic tinnitus or somatosound . However, the isolated term “tinnitus” conventionally refers to the neurophysiologic tinnitus.
Hyperacusis, in an unusual intolerance to ordinary environmental sounds . It be conceived as a “pathology” of the loudness, the subjective perception of sound level . Hyperacusis is an auditory disorder with or without hearing loss  where sounds of normal volume are perceived to be too loud or painful . Hyperacusis arises in the auditory system, either peripheral (myasthenia gravis, Bell’s palsy, Ramsay Hunt syndrome, Meniere syndrome, noise-induced hearing loss and other sensorineural auditory disorders) or central (migraine headaches, depression, head injury, William’s syndrome, multiple sclerosis, transient ischaemic attack, Lyme disease, Addison’s disease and stimulant drug dependency) [26,27].
Decreased sound tolerance (DST) consists not only of hyperacusis; it also consists of a fear of sound known as phonophobia or a strong dislike of sound called misophonia . Patients with misophonia or phonophobia have abnormally strong reactions of the limbic and autonomic nervous systems, but do not have a significant activation of the auditory system, as observed in hyperacusis . Patient’s reactions are correlated with the spectrum and intensity of sounds in hyperacusis while patients with misophonia react only to the sound’s meaning and to the context in which it occurs, whether or not it is loud for the individual. Furthermore, the subject may react to a given sound in a particular setting, but not in another one .
A Flow chart reporting the classification of various aspect of an altered auditory perception is showed in the figure 1.
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