Neuropsychology
Visual Neglect Laboratory
Three classic tasks, five fictional profiles, and one question worth getting right: is this person not attending to the left, or not seeing it?
Simulated — invented profiles, generated performance, original graphics
Learning objective
By the end you should be able to say why neglect is not blindness on one side, and what task signature distinguishes them.
About 30 minutes. Nothing you do here is saved or sent anywhere.
Not a test, and not for you
You are not being assessed and nothing here can assess anybody. Every result is generated from a rule for that fictional profile, and the tasks are simplified originals rather than clinical instruments. Real assessment of neglect uses a battery of tasks, observation of everyday behaviour, and a clinician.
- Answer the opening question.
- Pick a profile and run each of the three tasks. Learn what each profile's handwriting looks like.
- Turn the prompt on and off. Watch which profiles it rescues and which it only helps.
- Then take the blinded case in the challenge.
First, a judgement
Two fictional people both leave food on the left of the plate and both bump into door frames on their left.
The laboratory
Key terms
- Neglect
- Not attending to one side of space, or of an object. It is defined by what the person does, not by where the damage is.
- Line bisection
- Marking the midpoint of a line. One of the three tasks here.
- Cancellation
- Crossing out every instance of a target scattered across a page. Another of the three.
- Frame of reference
- What the neglected side is to the left of: the viewer, the page, or an individual object. The profiles here differ on this.
- Examiner prompt
- A cue drawing the person's attention towards the neglected side. Here it is something you switch on and off to see what it changes.
Line bisection
What this person produced
Reading this performance
The same performance in numbers
| Item | Result | Reading |
|---|
All five profiles on this task, side by side
| Profile | Unprompted | Prompted |
|---|
Challenge - one blinded case
What this demonstrates
Neglect is not blindness on one side
Someone with left field loss has a hole in the visual input and knows it. They move their eyes into the missing region, they can tell you what they have not seen, and given time and a prompt they find everything. Someone with neglect has the input and does not attend to it. They do not report anything missing, they do not spontaneously search the neglected side, and a prompt helps only while it lasts. The two can occur together, which is one of several reasons a single task is not enough.
The bisection error runs in opposite directions
Asked to mark the middle of a line, neglect produces a mark to the right of centre - the left of the line is under-weighted, so the perceived middle shifts towards the attended side. Field loss without neglect tends to produce a small error in the other direction, towards the blind side. Two people who both "miss things on the left" therefore err in opposite directions on the same task, which is a good demonstration that the surface description was hiding two different problems.
Neglect is organised in more than one frame
The copying task separates two patterns that look similar in casual description. One person leaves out everything on the left of the page: the space around them is what is neglected. Another draws every object but leaves the left half off each of them, including objects sitting on the right-hand side of the page. That second pattern is hard to explain as a failure to look far enough left, because the omitted parts are not on the left of anything except the object they belong to. Both frames occur, often together and to different degrees.
Prompting is not a cure and is not a test
A prompt rescues field loss completely: the strategy was already available and only needed the time. It improves neglect and does not abolish it, and for object-centred neglect an instruction about the page does nothing at all, because the page is not the frame that is failing. Improvement with cueing is therefore informative about mechanism, and is not a measure of severity.
The lesions behind it are heterogeneous
Neglect is not one thing with one location. It follows damage in several right-hemisphere sites, and the argument about which matters most has run for decades: inferior parietal cortex, the temporo-parietal junction, superior temporal cortex, frontal regions, and - on the evidence that most changed the debate - the white matter connecting them. Neglect after damage confined to a tract is precisely the disconnection case, and it is one of the reasons "the neglect area" is not a useful phrase.
For teaching elsewhere: take this activity as one self-contained block of HTML, on the clipboard or as a file. Either way it is styled so that it will not disturb the page you put it into.