Riddoch syndrome (also known as the "Riddoch phenomenon") is an ocular affectation often caused by lesions in the occipital lobe which limit the sufferer's ability to distinguish objects. Only moving objects in a blind field are visible, static ones being invisible to the patient. The moving objects are not perceived to have color or detail. The subject may only have awareness of the movement without visual perception of it (gnosanopsia), or the general shape of a moving object may be perceivable as a shadow like outline.

At least one patient was able to use a rocking chair—putting non-moving surroundings in relative motion to her head—to improve her motion perception. She eventually was able to do the same with just voluntary movement of her head.

Musical ear syndrome (MES) describes a condition seen in people who have hearing loss and subsequently develop auditory hallucinations. "MES" has also been associated with musical hallucinations, which is a complex form of auditory hallucinations where an individual may experience music or sounds that are heard without an external source. It is comparable to Charles Bonnet syndrome (visual hallucinations in visually impaired people) and some have suggested this phenomenon could be included under this diagnosis.

Musical hallucinations and MES have only become widely recognizable in the last few decades of research, but there are indications throughout history that have described symptoms of musical hallucinations. The Romantic composer Robert Schumann was said to have heard entire symphonies in his head from which he drew as inspiration for his music, but later in his life this phenomenon had diminished to just a note that played ceaselessly within his head. An alternative explanation is that his symptoms were caused by syphilis or mercury poisoning used for its treatment. The Russian composer Dmitri Shostakovich was also recorded as experiencing music hallucinations after some shrapnel was removed from his skull.

The most common cause of cortical blindness is ischemia (oxygen deprivation) to the occipital lobes caused by blockage to one or both of the posterior cerebral arteries. However, other conditions have also been known to cause acquired and transient cortical blindness, including:

- Bilateral lesions of the primary visual cortex

- Side effect of some anti-epilepsy drugs (AEDs)

- Creutzfeldt–Jakob disease, in association with a rapid onset of dementia

- Infection

- Head trauma to the occipital lobe of the brain

- Congenital abnormalities of the occipital lobe

- Eclampsia and, rarely, pre-eclampsia

- Hyperammonemia

The most common causes of congenital cortical blindness are:

- Traumatic brain injury (TBI) to the occipital lobe of the brain

- Congenital abnormalities of the occipital lobe

- Perinatal ischemia

- Encephalitis

- Meningitis

The prognosis of a patient with acquired cortical blindness depends largely on the original cause of the blindness. For instance, patients with bilateral occipital lesions have a much lower chance of recovering vision than patients who suffered a transient ischemic attack or women who experienced complications associated with eclampsia. In patients with acquired cortical blindness, a permanent complete loss of vision is rare. The development of cortical blindness into the milder cortical visual impairment is a more likely outcome. Furthermore, some patients regain vision completely, as is the case with transient cortical blindness associated with eclampsia and the side effects of certain anti-epilepsy drugs.

Recent research by Krystel R. Huxlin and others on the relearning of complex visual motion following V1 damage has offered potentially promising treatments for individuals with acquired cortical blindness. These treatments focus on retraining and retuning certain intact pathways of the visual cortex which are more or less preserved in individuals who sustained damage to V1. Huxlin and others found that specific training focused on utilizing the "blind field" of individuals who had sustained V1 damage improved the patients' ability to perceive simple and complex visual motion. This sort of 'relearning' therapy may provide a good workaround for patients with acquired cortical blindness in order to better make sense of the visual environment.

Some of the causes of integrative agnosia include stroke, traumatic brain injury, Alzheimer's disease, an anoxic episode following myocardial infarction, and progressive multifocal leukoencephalopathy.

Integrative agnosia is a sub-disease of agnosia, meaning the lack of integrating perceptual wholes within

knowledge. Integrative agnosia can be assessed by several experimental tests such as the Efron shape test, which

determines the specificity of the disease being Integrative.

This disease is often caused by brain trauma, producing medial ventral lesions to the extrastriate cortex. Affecting this region of the brain produces learning impairments: the inability to

integrate parts such as spatial distances or producing visual images from short or long-term memory.

Aphantasia is the suggested name for a condition where one does not possess a functioning mind's eye and cannot visualize imagery. The phenomenon was first described by Francis Galton in 1880, but has remained largely unstudied since. Interest in the phenomenon renewed after the publication of a study conducted by a team led by Prof. Adam Zeman of the University of Exeter, which also coined the term "aphantasia". Research on the subject is still scarce, but further studies are planned.

Gestaltzerfall (German for "shape decomposition") refers to a type of visual agnosia and is a psychological phenomenon where delays in recognition are observed when a complex shape is stared at for a while as the shape seems to decompose into its constituting parts. With regards to kanji, a study has shown that delays are most significant when the characters are of the same size. When characters to recognize are of different sizes, delays are observed only when they are of different patterns.

The phenomenon was first described and named by C. Faust in 1947 as a symptom of the bilateral region of the parieto-occipital sulcus after a through and through bullet wound of this region. Afterwards, when the subject stared at a truck for a while the truck seemed to decompose into its motor, chassis, driver cab and the person could only focus on one of these parts until he briefly closed his eyes or looked away which reset the shape to the complete truck again.

The characteristic of orthographic satiation as opposed to semantic satiation is that meaning remains intact. It was suggested that this is different from semantic satiation and from the stimulus familiarization effect because orthographic satiation occurs after the perceivers have access to lexical meaning.

Tullio phenomenon, sound-induced vertigo, dizziness, nausea or eye movement (nystagmus) was first described in 1929 by the Italian biologist Prof. Pietro Tullio. (1881–1941) During his experiments on pigeons, Tullio discovered that by drilling tiny holes in the semicircular canals of his subjects, he could subsequently cause them balance problems when exposed to sound.

The cause is usually a fistula in the middle or inner ear, allowing abnormal sound-synchronized pressure changes in the balance organs. Such an opening may be caused by a barotrauma (e.g. incurred when diving or flying), or may be a side effect of fenestration surgery, syphilis or Lyme disease.

Patients with this disorder may also experience vertigo, imbalance and eye movement set off by changes in pressure, e.g. when nose-blowing, swallowing or when lifting heavy objects.

Tullio phenomenon is also one of the common symptoms of superior canal dehiscence syndrome (SCDS), first diagnosed in 1998 by Dr. Lloyd B. Minor, The Johns Hopkins University, Baltimore, United States.

Aphantasia is similar to invisible disabilities such as face blindness, word blindness, and tone deafness, though aphantasia itself has not been associated with any functional deficits.

In most studies, a majority of cell phone users report experiencing occasional phantom vibrations or ringing, with reported rates ranging from 27.4% to 89%. Once every two weeks is a typical frequency for the sensations, though a minority experience them daily. Most people are not seriously bothered by the sensations.

The cause of phantom vibrations is not known. Preliminary research suggests it is related to over-involvement with one's cell phone. Vibrations typically begin occurring after carrying a phone for between one month and one year. It has been suggested that, when anticipating a phone call, the cerebral cortex may misinterpret other sensory input (such as muscle contractions, pressure from clothing, or music) as a phone vibration or ring tone. This may be understood as a human signal detection issue, with potentially significant influences from psychological attributes. Factors such as experiences, expectations, and psychological states influence the threshold for signal detection. Some phantom vibration experiences may be a type of pareidolia and can therefore be examined as a psychological phenomenon influenced by individual variances in personality, condition, and context. Attachment anxiety can also be seen as a predictor for the frequency of phantom vibration experiences since it is associated with psychological attributes related to insecurity in interpersonal relationships.

Echophenomenon (also known as echo phenomenon) is "automatic imitative actions without explicit awareness" or pathological repetitions of external stimuli or activities, actions, sounds, or phrases, indicative of an underlying disorder.

The echophenomena include repetition:

- echolalia – of vocalizations (the most common of the echophenomena)

- echopraxia – of actions

- echomimia – of facial expressions

- echographia – of words that are written or typed

- echoplasia – physically or mentally, tracing contours of objects

- echolalioplasia – involving sign language, described in one individual with Tourette syndrome ().

- echologia – of words or sounds in thought

Inverse Marcus Gunn phenomenon is a rare condition that causes the eyelid to fall upon opening of the mouth. In this case, trigeminal innervation to the pterygoid muscles of the jaw is associated with an inhibition of the branch of the oculomotor nerve to the levator palpebrae superioris, as opposed to stimulation in Marcus Gunn jaw-winking.

Entoptic images have a physical basis in the image cast upon the retina. Hence, they are different from optical illusions, which are perceptual effects that arise from interpretations of the image by the brain. Because entoptic images are caused by phenomena within the observer's own eye, they share one feature with optical illusions and hallucinations: the observer cannot share a direct and specific view of the phenomenon with others.

Helmholtz comments on phenomena which could be seen easily by some observers, but could not be seen at all by others. This variance is not surprising because the specific aspects of the eye that produce these images are unique to each individual. Because of the variation between individuals, and the inability for two observers to share a nearly identical stimulus, these phenomena are unlike most visual sensations. They are also unlike most optical illusions which are produced by viewing a common stimulus. Yet, there is enough commonality between the main entoptic phenomena that their physical origin is now well understood.

Entoptic phenomena (from Greek ἐντός "within" and ὀπτικός "visual") are visual effects whose source is within the eye itself. (Occasionally, these are called entopic phenomena, which is probably a typographical mistake.)

In Helmholtz's words; "Under suitable conditions light falling on the eye may render visible certain objects within the eye itself. These perceptions are called "entoptical"."

Diplophonia, also known as diphthongia, is a phenomenon in which a voice is perceived as being produced with two concurrent pitches. Diplophonia is a result of vocal fold vibrations that are quasi-periodic in nature. It has been reported from old days, but there are no uniform interpretation of established mechanisms. It has been established that diplophonia can be caused by various vocal fold pathologies, such as vocal folds polyp, vocal fold nodule, recurrent laryngeal nerve paralysis or vestibular fold hypertrophy.

Although treatment may be unnecessary, there may be social implications, especially in young children when venturing from a supportive home environment to a public environment (e.g., starting school). Continued support, including monitoring behavior and educating the child about his or her appearance as seen by others, is encouraged. Gradual or sudden withdrawal from interaction with others is a sign that may or may not be related to such behavior. Studies are being conducted to elucidate these implications.

Coloboma of optic nerve, is a rare defect of the optic nerve that causes moderate to severe visual field defects.

Coloboma of the optic nerve is a congenital anomaly of the optic disc in which there is a defect of the inferior aspect of the optic nerve. The issue stems from incomplete closure of the embryonic fissure while in utero. A varying amount of glial tissue typically fills the defect, manifests as a white mass.

Thought blocking (also known as ), a phenomenon that occurs in people with psychiatric illnesses (usually schizophrenia), occurs when a person's speech is suddenly interrupted by silences that may last a few seconds to a minute or longer. When the person begins speaking again, after the block, they will often speak about a subject unrelated to what was being discussed when blocking occurred. It is described as being experienced as an unanticipated, quick and total emptying of the mind. People with schizophrenia commonly experience thought blocking and may comprehend the experience in peculiar ways. For example a person with schizophrenia might remark that another person has removed their thoughts from their brain.

When doctors diagnose thought blocking, it is important that they consider other causes of pauses in speech and expression, such as petit mal seizures, aphasia, hesitation brought on by anxiety, or slow thought processes. When looking for schizophrenia they may look for thought blocking. It is a common issue with schizophrenia patients.

Vision in the affected eye is impaired, the degree of which depends on the size of the defect, and typically affects the visual field more than visual acuity. Additionally, there is an increased risk of serous retinal detachment, manifesting in 1/3 of patients. If retinal detachment does occur, it is usually not correctable and all sight is lost in the affected area of the eye, which may or may not involve the macula.

Dissociated vertical deviation (DVD) is an eye condition which occurs in association with a squint, typically infantile esotropia. The exact cause is unknown, although it is logical to assume it is from faulty innervation of eye muscles.

Dissociation refers to the situation where the innervation of one eye causes it to move involuntarily and independently of the other eye. Usually both eyes work together as described by Hering's and Sherrington's laws of innervation. A DVD is a slow upward and sometimes temporal movement of one eye, with cortical suppression of the vision in that eye while it is deviated. On returning downward and possibly inward to take up fixation, the DVD slow movement will be reversed.

The dissociative movement seen 'objectively' should not be confused with the dissociation that occurs 'subjectively' - as when the brain begins to not visualise both images simultaneously (by ignoring or suppressing vision in that eye).

Auditory exclusion is a form of temporary loss of hearing occurring under high stress.

As such it is related to tunnel vision and "the slowing of time in the mind".

The phenomenon is discussed in the literature on law enforcement officers and soldiers.

In 2016, the attorney for Tulsa police officer Betty Shelby wanted to the jury to hear about how auditory exclusion could have played a role when the officer fatally shot Terence Crutcher, an unarmed 40-year-old black male.