Posts Tagged Hemianopsia

[WEB PAGE] SeeDrivePro Visual Field Test – EyeLab – Accredited Online Sight Tests

EyeLab Visual Field Test

A simulated ‘Esterman Visual Field Test’

(EVFT) for commercial vehicle drivers

Please select one of the following two options:

First Time User Instructions Experienced EVFT User

EVFT enables drivers to test if they have the required field of vision as defined in the Regulations in the Appendix below.   This is a legal requirement for commercial vehicle drivers in the UK and many other countries.

EyeLab recommends that EVFT is checked every 12 months when taking the SeeDrivePro routine test.  This will conform to the DVLA  ‘Esterman Test’ which is described in the Regulations.

In addition to the vision test SeeDrivePro commercial vehicle drivers should have a minimum standard of visual field (peripheral vision) as tested with an Esterman Visual Field Test.

What you will need

A computer monitor or TV with a minimum horizontal width of 16 inches (41cms) or a laptop connected to the internet which has a HDMI output plus a HDMI cable to connect your laptop to the monitor.

This test should be supervised to ensure that you remain correctly positioned throughout the test.

Set-up instructions

To Continue visit Site —-> https://www.eyelab.co.uk/seedrivepro-visual-field-test/

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[VIDEO] Simple Test for Vision After Stroke (Visual Field Test) – YouTube

Famous Physical Therapists Bob Schrupp and Brad Heineck demonstrate an easy to perform visual test for someone who has had a stroke or cerebral vascular accident.

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[VIDEO] What is Hemianopsia, Causes,Types,Symptoms,Diagnosis,Treatment – YouTube

What is hemianopsia

Overview: Hemianopsia is a loss of vision in half of your visual field of one eye or both eyes. Common causes are:

  • stroke
  • brain tumor
  • trauma to the brain

Normally, the left half of your brain receives visual information from the right side of both eyes, and vice versa.

Some information from your optic nerves crosses to the other half of the brain using an X-shaped structure called the optic chiasm. When any part of this system is damaged, the result can be a partial or complete loss of vision in the visual field.

What causes hemianopsia?

Hemianopsia can occur when there’s damage to the:

  • optic nerves
  • optic chiasm
  • visual processing regions of the brain

The most common causes of brain damage that can result in hemianopsia are:

  • stroke
  • tumors
  • traumatic head injuries

Less commonly, brain damage can also be caused by:

  • aneurysm
  • infection
  • exposure to toxins
  • transient events, such as seizures or migraines

Types of hemianopsia

With hemianopsia, you can see only part of the visual field for each eye. Hemianopsia is classified by the part of your visual field that’s missing:

bitemporal: outer half of each visual field

homonymous: the same half of each visual field

right homonymous: right half of each visual field

left homonymous: left half of each visual field

superior: upper half of each visual field

inferior: lower half of each visual field

via What is Hemianopsia, Causes,Types,Symptoms,Diagnosis,Treatment – YouTube

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[ARTICLE] Visual processing speed in hemianopia patients secondary to acquired brain injury: a new assessment methodology – Full Text

Abstract

Background

There is a clinical need to identify diagnostic parameters that objectively quantify and monitor the effective visual ability of patients with homonymous visual field defects (HVFDs). Visual processing speed (VPS) is an objective measure of visual ability. It is the reaction time (RT) needed to correctly search and/or reach for a visual stimulus. VPS depends on six main brain processing systems: auditory-cognitive, attentional, working memory, visuocognitive, visuomotor, and executive. We designed a new assessment methodology capable of activating these six systems and measuring RTs to determine the VPS of patients with HVFDs.

Methods

New software was designed for assessing subject visual stimulus search and reach times (S-RT and R-RT respectively), measured in seconds. Thirty-two different everyday visual stimuli were divided in four complexity groups that were presented along 8 radial visual field positions at three different eccentricities (10o, 20o, and 30o). Thus, for each HVFD and control subject, 96 S- and R-RT measures related to VPS were registered. Three additional variables were measured to gather objective data on the validity of the test: eye-hand coordination mistakes (ehcM), eye-hand coordination accuracy (ehcA), and degrees of head movement (dHM, measured by a head-tracker system). HVFD patients and healthy controls (30 each) matched by age and gender were included. Each subject was assessed in a single visit. VPS measurements for HFVD patients and control subjects were compared for the complete test, for each stimulus complexity group, and for each eccentricity.

Results

VPS was significantly slower (p < 0.0001) in the HVFD group for the complete test, each stimulus complexity group, and each eccentricity. For the complete test, the VPS of the HVFD patients was 73.0% slower than controls. They also had 335.6% more ehcMs, 41.3% worse ehcA, and 189.0% more dHMs than the controls.

Conclusions

Measurement of VPS by this new assessment methodology could be an effective tool for objectively quantifying the visual ability of HVFD patients. Future research should evaluate the effectiveness of this novel method for measuring the impact that any specific neurovisual rehabilitation program has for these patients.

Background

Vision is the dominant sensory function in humans because visual search and reach tasks are crucial to efficient performance of the main activities of daily life [12]. The term visual processing speed (VPS), an important variable of visual sensory function, is the amount of time needed to make a correct interaction with a visual stimulus [34]. The term correct interaction is the effective realization of a complete executive action of visual search and reach [5], e.g., visualizing a glass of water placed on a table and then grasping it by precise eye-hand coordination (EHC). Accordingly, the VPS variable defines the global reaction time (RT) that is composed of two additive RT sub-variables: search reaction time (S-RT) and reach reaction time (R-RT) [6,7,8]. Furthermore, VPS is mainly interdependent on intrinsic visual cognitive processing mechanisms, the complexity of the determined stimulus to be recognized (defined principally in terms of size, contrast, semantic content, and number of traces or interior angles [910]), the number of distractor stimuli surrounding it, and the distance from the point of fixation to the particular stimulus that the person is tasked to identify (eccentricity) [411,12,13]. Thus, VPS is a quantifiable parameter that objectively reflects a subject’s global visual ability.

Recent findings in the field of visual psychophysics show that having adequate VPS is necessary and dependent upon the proper functioning of six main brain-processing systems: auditory-cognitive, attentional, working-memory, visuocognitive, visuomotor, and executive [14,15,16,17,18]. Consequently, an acquired brain injury (ABI) that affects any of these cerebral processing systems could decrease the VPS.

ABI is one of the most important and disabling public health problems of our era due to the high incidence and prevalence [19]. Following an ABI, between 30 and 85% of patients will experience some type of visual dysfunction [2021], especially homonymous visual field defects (HVFDs) secondary to lesions involving the visual afferent pathways posterior to the chiasm [22]. Eye tracking technology has shown that HVFDs prevent patients from having the appropriate control of their oculomotor systems [23,24,25,26]. This is especially apparent in the saccadic system, because it is interdependent with the covert attention mechanisms associated with peripheral vision [2728]. Thus, patients with HVFDs tend to perform search tasks using unconscious compensatory head movements [252930] and employ longer total search times, more frequent fixations, and shorter saccades than normal controls [2331,32,33,34,35,36,37]. Therefore, these patients experience a significant reduction in their quality of life and functional independence. They complain that the time they have to invest in carrying out their daily activities is much greater than before suffering from HVFDs [3338,39,40]. In this regard, in recent years the scientific community has joined efforts to develop increasingly effective neurovisual rehabilitation training programs (NVRTPs) for these patients [41]. Different forms of NVRTPs have been developed, including compensatory NVRTP (C-NVRTP), restitution NVRTP (R-NVRTP), and substitution NVRTP (S-NVRTP) [41,42,43,44].[…]

 

via Visual processing speed in hemianopia patients secondary to acquired brain injury: a new assessment methodology | SpringerLink

Fig. 2

Fig. 2 Head Tracker System incorporated in the new software to measure the number of degrees of absolute head movements (dHM) performed by the study subjects, along the coordinate axes “X” and “Y”, while they performed the test. It consisted of specific software capable of detecting human faces (a), a fluorescent light (b), and a web camera (c) that registered the specific movement of a green point placed on a human mask positioned on the back of the subject’s head and neck (d.1 and d.2). The subject had to remain seated in front of the digital resistive-touch whiteboard at a distance of 40 cm (15.7 in.) and at 70 cm (27.5 in.) from the webcam

 

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[ARTICLE] Reversing Hemianopia by Multisensory Training Under Anesthesia – Full Text

Hemianopia is characterized by blindness in one half of the visual field and is a common consequence of stroke and unilateral injury to the visual cortex. There are few effective rehabilitative strategies that can relieve it. Using the cat as an animal model of hemianopia, we found that blindness induced by lesions targeting all contiguous areas of the visual cortex could be rapidly reversed by a non-invasive, multisensory (auditory-visual) exposure procedure even while animals were anesthetized. Surprisingly few trials were required to reinstate vision in the previously blind hemisphere. That rehabilitation was possible under anesthesia indicates that the visuomotor behaviors commonly believed to be essential are not required for this recovery, nor are factors such as attention, motivation, reward, or the various other cognitive features that are generally thought to facilitate neuro-rehabilitative therapies.

Introduction

Extensive damage to the visual cortex on one side of the brain produces blindness in the opposite hemifield (hemianopia) despite the sparing of other visual centers far from the site of the physical insult (Sand et al., 2013Goodwin, 2014). Of special note is the superior colliculus (SC), a midbrain structure that plays a major role in detecting, localizing, and orienting to visual targets. Its multisensory neurons allow it to use non-visual cues to facilitate this process (Stein and Meredith, 1993), and its location in the midbrain ensures that it is not directly damaged by a hemianopia-inducing cortical insult. Yet, as shown in the cat model of hemianopia, the loss of visual responses in the multisensory layers of the SC and the total absence of visual detection and orientation responses to contralateral visual stimuli following lesions of visual cortex reveal that it too is compromised, presumably via secondary excitotoxic injuries that may alter other input structures such as the basal ganglia (Jiang et al., 20092015). Interestingly, the dysfunction of SC appeared to be limited to its visual role. Its other sensory representations and sensorimotor roles remained intact: SC-mediated auditory and tactile detection and orientation responses were readily elicited (see also Sprague and Meikle, 1965).

Previously it was shown that hemianopia could be reversed using a non-invasive multisensory training paradigm (Jiang et al., 2015). The procedure consisted of presenting cross-modal combinations of spatiotemporally congruent auditory-visual cues in the blind hemifield of alert animals engaged in a sensory localization task. Because the animals were not deafened by the cortical lesion, they readily responded to the auditory-visual stimulus complex. After only a few weeks of daily multisensory training sessions, a striking change occurred: not only could the animals now detect and localize a visual stimulus throughout the previously blind hemifield, but they could also discriminate elementary visual patterns there. Visual responses that had been lost in the multisensory layers of the ipsilesional SC also returned, and cortico-SC circuits normally engaged in multisensory integration (i.e., projections from the anterior ectosylvian sulcus, AES) were found to be crucial for the recovery. The recovery could not be induced by training with visual or auditory cues alone. In an important series of studies in human patients, Làdavas and colleagues (Bolognini et al., 2005Leo et al., 2008Passamonti et al., 2009Dundon et al., 2015a,b) used a similar training paradigm and also met with success in evoking contralesional visual responses.

It is commonly believed that the success of this rehabilitative paradigm is a retraining of the visuomotor targeting behavior itself (see, review in Dundon et al., 2015a). In this case, the key factor would be the orienting action (initially elicited by the auditory stimulus) in the presence of the visual stimulus. Also, if true, it is reasonable to hypothesize that the effectiveness of this paradigm would be facilitated by other factors such as motivation, attention, arousal, and reinforcement, as these are commonly believed to enhance most neuro-rehabilitative therapies. An alternative explanation, however, is that the paradigm operates via the brain’s inherent mechanisms for multisensory plasticity, which operate independent of these factors and can be engaged under anesthesia (Yu et al., 2013). In this case, the requirement would only be repeated, reliable exposure to the visual-auditory stimulus complex in the blinded hemifield. The present study examined this possibility directly.

Materials and Methods

Adult mongrel cats (four male, three female) were obtained from a USDA-licensed commercial animal breeding facility (Liberty Labs, Waverly, NY, USA). The experimental procedures used were in compliance with the National Institutes of Health “Guide for the Care and Use of Laboratory Animals” (8th edition, NRC 2011) and approved by the Institutional Animal Care and Use Committee at Wake Forest School of Medicine. Each animal was first screened to ensure that it was tractable and responded to visual and auditory stimuli in both hemifields. All efforts were made to minimize the number of animals used.

Visual Detection and Orientation Testing

Visual orientation capabilities were quantitatively evaluated in a semicircular perimetry arena using previously described methods (see Jiang et al., 2015, see also Figure 1A). Animals were maintained at 80%–85% of body weight and obtained most of their daily food intake during, or immediately after, each behavioral session. Each animal was first trained to fixate directly ahead at a food reward held in forceps by one experimenter and protruded through a hole in the front wall of the apparatus 58 cm ahead at the 0° fixation point. Trial initiation was always contingent upon the animal establishing fixation. Once released by the animal handler (a second experimenter), the animal was required to move directly ahead to obtain the food reward. It was then trained to respond to the test stimulus (a white ping-pong ball at the end of a stick) presented at any 15° interval from 105° left to 105° right. This required little training as animals responded to the stimulus almost reflexively. Stimuli were presented manually and introduced suddenly from behind a black curtain while the animal was fixating. Additionally, on some trials, the ball remained hidden behind the opaque curtain and was tapped on the side of the apparatus to produce an auditory stimulus. If the animal oriented to and approached any test stimulus it was rewarded there, but could also move directly ahead to obtain a similar reward at the fixation point. The animal handler did not know the location of the upcoming test stimulus. This was determined by the experimenter holding the food reward, who also ensured that the trial did not begin if the animal had broken fixation. The verbal command “Go” triggered the release of the animal. “Catch trials” in which no stimulus was presented were interleaved with test trials at different locations to encourage the animal to minimize breaks in fixation, scanning movements, and “false” responses. Generally, in a given session, each of the 15° locations was tested at least 4–5 times. With few exceptions, the total number of trials/location was at least 100. The training criterion was an average of 95% correct responses. All animals reached criterion readily, had normal visual fields, and their weekly weight records revealed stable weight profiles.

Figure 1. The testing, training, and multisensory exposure paradigms. (A) Visual and auditory detection/localization capabilities were first assessed on both sides of space using a simple behavioral task. Cats were trained to fixate forward at 0° then orient to, and directly approach, a visual or auditory stimulus at any location in space. Visual stimuli were produced by lowering a ping pong ball below an obscuring curtain, and auditory stimuli were produced by tapping the ball against the apparatus wall while still obscured by the curtain. (B) Following surgery, a rehabilitation paradigm consisted of weekly sessions in which animals were exposed to cross-modal cues while anesthetized. As shown by the schematic at the lower left, the central LED (at 0°) of the display was briefly illuminated to signal the onset of the trial. It was followed by the combined LED-broadband noise burst at 45° in the contralesional hemifield. Traces illustrate the onset and duration of the stimuli. Panel (A) adapted from Jiang et al. (2015).

Continue —->  Frontiers | Reversing Hemianopia by Multisensory Training Under Anesthesia | Frontiers in Systems Neuroscience

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[VIDEO] Hemianopia conversation technique – YouTube

Left Homonymous hemianopia ways of meeting and talking to people

 

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[Abstract] Computer-Based Cognitive Rehabilitation in Patients with Visuospatial Neglect or Homonymous Hemianopia after Stroke

Abstract

Objectives: The purpose of this pilot study was to investigate the feasibility and effects of computer-based cognitive rehabilitation (CBCR) in patients with symptoms of visuospatial neglect or homonymous hemianopia in the subacute phase following stroke.

Method: A randomized, controlled, unblinded cross-over design was completed with early versus late CBCR including 7 patients in the early intervention group (EI) and 7 patients in the late intervention group (LI). EI received CBCR training immediately after inclusion (m = 19 days after stroke onset) for 3 weeks and LI waited for 3 weeks after inclusion before receiving CBCR training for 3 weeks (m = 44 days after stroke onset).

Results: CBCR improved visuospatial symptoms after stroke significantly when administered early in the subacute phase after stroke. The same significant effect was not found when CBCR was administered later in the rehabilitation. The difference in the development of the EI and LI groups during the first 3 weeks was not significant, which could be due to a lack of statistical power. CBCR did not impact mental well-being negatively in any of the groups. In the LI group, the anticipation of CBCR seemed to have a positive impact of mental well-being.

Conclusion: CBCR is feasible and has a positive effect on symptoms in patients with visuospatial symptoms in the subacute phase after stroke. The study was small and confirmation in larger samples with blinded outcome assessors is needed.

via Computer-Based Cognitive Rehabilitation in Patients with Visuospatial Neglect or Homonymous Hemianopia after Stroke – ScienceDirect

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[VIDEO] Hemianopia – Half blind – YouTube

This is an attempt to show people how I see the world since my brain injury 8 years ago. This is what I see when I’m going shopping… I hate going shopping… I rarely go full shopping….. My left side of vision is missing, it’s not really black, it’s just not there, but I can’t explain it… and what I have left, is what you see here… My camera caught it all perfectly, sun glare as well… So if I don’t recognise you in the street, it’s really because I can’t see your face. If I need to see your face, I look for the right side edge of your face and look above you… that helps me see more of your features. But to be honest, I’ve kind of got used to not seeing people’s faces. I look at the floor a lot so I can see people’s feet, so I can sort of work out where they are if they are too close to me. Gradually, over 8 years I have adapted to doing things, walking, etc on the right. I stop in mid walking sometimes because I saw a person in front of me, then they vanished to my left and I wasn’t sure how close to me they were and I didn’t want to bump into them…. I cope better in wider spaces. Narrow corridors look even more narrow. I discreetly use my hands to touch anything that might be too close, so that I know to move myself away. I still walk into things and get hurt. If I turn my head too quickly, then I go off balance and sometimes fall over. It is very frightening when you can’t see properly, but look normal to everyone else. I’m not too bad if I’m with someone else. I constantly rely on touch… Hence doing Papiér Maché instead of drawing or painting. Also, I still get lost and wonder where I am, even sometimes going past my own house… I haven’t read a book in years, and I used to like reading… I couldn’t work out why I couldn’t see the words properly, and they kept vanishing, and the bits that I could see were double vision – then I had prisms fitted in my glasses lenses, which helped with the double vision, but I still couldn’t work out why I couldn’t see properly. I was officially diagnosed in January 2017. The Neurologist said despite all that, I had made some very good ways of trying to cope… It still is a struggle, but I do my best.

via Hemianopia – Half blind – YouTube

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[VIDEO] SYMPTOMS OF HEMIANOPSIA – YouTube

 

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[BLOG POST] Management hemianopia

Hemianopia, partial loss of the field of vision, is a condition usually the result of a stroke although other neurological disorders such as tumours can be responsible.

From the Greek; hemi – half, an – without, opia – sight.

Damage to an individual’s brain in the area responsible for interpreting visual input is the most common cause;

Paris with full visual fields.png

Normal field of vision

Paris with hemianopia.png

Hemianopia

The thing about hemianopia is that often the person experiencing the condition is unaware. Imagine the entire right side of your world stops existing; your brain, just as with your physiological blind-spot very quickly recovers and compensates.

People who have experienced strokes will not uncommonly eat a meal and leave half the plate, not because they can’t see it (which they can’t), but because for that person there is no right or left side of the plate.

leftfood.png

We call this situation neglect. I guess that is apposite.

I first encountered this in Oliver Sack’s case histories. I can remember the story of a man waking-up in bed to find a strange object beside him; inert, disconnected – it was his own leg. (This might have been Alien Hand Syndrome, that is for another day.)

(For this reason, medical students, if you ever talk with someone who has experienced a major stroke, always make sure you are in their field of vision and not presenting as a disembodied voice.)

Once understanding this concept, I thought I would stretch the idea to include the way that certain branches of management operate.

It is all too easy for me to pick hospital management, but, what the heck.

Imagine you are running an organisation – it is perhaps doing OK, books balanced, care, treatment, production all at levels you anticipated at the start of the year; the plan is on plan. Beautiful; you can even go on holiday and chill-out.

If back home things go wrong; I don’t know, perhaps, the money that was thought to be in the bank is actually a deficit or, the equipment you have been using to undertake operations is in some way faulty, you have two options.

One, investigate, get as much information as possible, conclude and communicate.

The other, is to do the above, but pretend all is OK; assume that everything will be well – this, the ostrich strategy you might call it is more common within organisations than at first might seem logical; we have the 2007/8 Global Financial Crisis as a case study.

breugel the fight between carnival and lent 1559.jpg

Much analysis has happened since that time and is ongoing; in healthcare, our equivalent is the Mid Staffordshire Hospitals – is disaster the wrong word*? People running so fast on a treadmill that if they get off the uncertainty is more frightening than their high-speed collapse.

Good, clever, insightful people become blinded to what is obvious; hemianopia. It is there, it is clear to everyone else, but in the case of the afflicted it doesn’t exist.

Other words are lacuna, scotoma, absence.

Through careful therapy, a person can recover from hemianopia – utilising mirror-neurones, physical and psychological treatments, that which was lost can return.

How do we support those caught in management hemianopia to recover? Is there a treatment or a means of defence?

Be open, honest, vulnerable and candid.

Don’t hide behind false prophets or slogans.

Acknowledge that the world is never entirely knowable; accept dissonance. Ask for help.

And, if the humility isn’t there? If the situation is extreme and the walls falling-down?

What would you do?

head in the sand.jpg

*Officially it was a ‘scandal’

via Management hemianopia – almondemotion

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