Simultanagnosia - When Brain Lesions Suddenly Destroy Perception
What is simultanagnosia?
This is a disorder of a neurological nature that is considered rare. "It is produced by bilateral posterior parietal lobe injury and contains three components of simultanagnosia (failure to concurrently detect more than just one fragment of an object). It is also composed of optic ataxia (diminished visual direction of mobility of the limbs and the body itself), and apraxia of gaze (weakness to volitionally direct gaze notwithstanding the requisite motor substrate) regularly linked with homonymous lower visual field loss." (Philip, 2016) It is characterized by an individuals inability to perceive more than one single item at one time. It is considered a visual attention issue. Simultanagnosia is one of the three segments of a syndrome known as Balint's. It severely affects a person's visuospatial processing, or data processing when it comes to the representation of space.
How it's Diagnosed and Symptoms
It is known that simultanagnosia happens due to lesions that are bilateral between the occipital lobe and the parietal lobe. The lesions could happen due to a stroke or some other kind of traumatic injury to the brain. Symptoms could also occur over time as part of a degenerative disorder. Since simultagnosia is part of Balint's syndrome, it's essential to investigate the signs of the syndrome itself. We can imagine an individual arising from bed in the morning, but they can not distinguish where the clothes drawers are that hold the clothes. At first, the individual may believe that they are perhaps a bit tired, but then they realize that they can't seem to find where the wall ends, and where the room's entrance door begins. The individual wants to find their phone to get help, but can't find their cell phone. Another family may tell that individual that the phone was right in front of them the whole time. What could be wrong with the person? Is the individual going blind? How could that be, if the eye doctor mentioned that the eyes are in perfect shape, and that vision is better than 20/20? In this frightening scenario, an ophthalmologist may end up giving a referral to a neurologist. This is because Balint's syndrome, and simultagnosia, are neurological conditions. Two of the other conditions that make up Balint's is oculomotor apraxia, which is where a person can't move their eyes toward a single object. Then there's optic ataxia, which happens when an individual cannot reach for something in front of them that they are directly looking at. Finally, there's our primary focus: visual simultagnosia. This is a complete inability for the individual to see the 'whole picture.' The individual will only be able to see an object, or a part, out of the whole field of vision. If someone were to show this afflicted individual a picture of a house, they may only see a door, or a window, but never the entire image of a house. A person may be shown a wreath with a bow on it, and then when asked, "What is this?" The individual may reply "bow" when they should have said 'wreath.' A patient may complain of blurry vision or being clumsy as they persistently bump into things. They may also complain of tunnel vision and issues with reading.
Neurological Basis (CNS STructures Involved)
It was discovered that "bilateral gray matter injury amidst the central frontal area (BA 46), cuneus, calcarine, and parieto-occipital fissure, in addition to right hemisphere parietal lesions in intraparietal and postcentral gyri, were correlated with simultanagnosia. More extensive research of the white matter focused on tractography showed relationships with bilateral injury to important pathways inside of the visuospatial recognition passageways. This included the superior longitudinal fasciculus, the inferior frontal-occipital fasciculus, and the inferior longitudinal fasciculus. It was concluded that damage was done to the parieto-occipital sections and the intraparietal sulcus, in unison, with bilateral white matter discontinuities in the visuospatial attention network, have to do with the feeble visual processing of many objects and the decline and absence of processing velocity characteristic of simultanagnosia."(Chechlacz, 2012) Ultimately, damage to the parietal cortex may cause simultanagnosia.
Functional Deficits and Effects on ADLs (Activities of daily living)
What are functional deficits? "Practical decline in more complicated activities – generally known as instrumental activities of daily living - regularly happens first; this constitutes housework, recreation activities, preparation and economic transactions. Succeeding functional deterioration attacks self-care activities, known as Activities of Daily Living, including bathing, dressing, eating, and even transferring." (Weston, 2011) A person with simultanagnosia will have to depend and heighten their other senses to navigate their world. They may have to have one hand on the bathroom sink in other to have an idea of where it is while they are in the bathroom. The individual may have to put toothpaste directly in the mouse, instead of initially on a toothbrush. The affected individual may have a difficult or impossible time using table eating utensils, as they will not be able to use their vision to direct their hand to pick up the handle of any spoon, knife or fork.
Those who suffer from simultanagnosia have a difficult time, as they are not genuinely blind through vision, but more through neurological processes. These individuals may be helped with occupational therapy, which can help their recover a semblance of independence. A therapist may suggest audio books instead of actual books or a high-quality radio instead of having a television. It's important to note that it's harder to diagnose this condition in children, as parents will often say that the child is careless or clumsy during their everyday living activities. The child may also have issues with reading and writing letters and may be inadequate performers at school. Crowded places may be uncomfortable to the individual, and the child may have problems dressing themselves as well. This led me to think of a research question:
Would a Balint's syndrome and simultanagnosia education program change patient diagnosis and treatment in children that have difficulties with clumsiness, reading, and activities of daily living?
Such an education program would be worth investigating, as a child may immediately be diagnosed with an over-hyped or 'popular' diagnosis, and treated with medication that is entirely unnecessary, and unhelpful, with a lack of understanding and absence of much needed occupational therapy.
© 2018 Charlotte Doyle