So I really thought that I’d written a post about Unilateral Neglect before but apparently I’m just imagining that! Perhaps my confusion is because I did write an essay about it for the first course I took last year, and hence forth I’ve become all muddled and confuddled that I can no longer differentiate from the work I ‘have to do’ and the blog posts I enjoy doing…
Anyway, this is the most perfect time for me to write about unilateral (or hemispatial) neglect, as my dog appears to be displaying the symptoms! Brilliant isn’t it? I shouldn’t be this excited but I can’t help it.
She is a 16 year old Whippet x. Lurcher who used to spend her days chasing bunnies and sometimes catching them, but now just potters about the place and would rather just stare at a field of rabbits and keep walking than bother to do anything about them. A few months ago Barley had a stroke, she suffered severe left side weakness and although has gained a lot of mobility back still has a slightly wonkey head. I believe she is still having small strokes and that she must have had one about a fortnight ago that affected her posterior parietal cortex. My reasons for suspecting this are outlined below, after my brief explanation of unilateral neglect symptoms in humans.
Okay, so here goes the ‘science’. Hemispatial neglect can occur following damage to the right or left posterior parietal cortex, most commonly occurring however in the right and usually as a result of a stroke. The form of neglect can be both extrapersonal, representational and/or personal. In right hemispherical damage the effects tend to be longer lasting and more severe, though most patients do recover over time.
In cases of extrapersonal neglect patients fail to be aware of objects on the contralateral side of their lesion, in most cases this means that they neglect objects in the left side of space. For patients to be diagnosed with hemispatial neglect no other explanation such as a motor or sensory deficit can be present (Vallar, 1998). This form of neglect can involve near space (or peripersonal space) or far space, or both. Often patients will recover over time from hemispatial neglect syndrome. It’s common for these patients to fail to draw the left hand side of a picture, as illustrated below, or for them to even eat food only from the right hand side of their plate and not realise that there is still food on the left to be eaten.
Figure illustrates the left side neglect of a patient.
In these cases patients neglect the contralesional space in their memories and imagination of places, objects and people. Representational neglect is far more common to right hemispherical damage and is found in conjunction with the extrapersonal visuospatial neglect described above (Bartolomeo, D’Erme, & Gainotti, 1994).
Personal neglect differs in that the patient fails to recognise or use parts of their own body that are on contralateral side of their brain damage. Patients are reported to be unaware of their own limbs, claiming for example that the left leg attached to them belongs to somebody else and is not theirs. This form of neglect is less common than that of extrapersonal neglect, and may involve additional regions of damage. Right personal neglect following a left sided lesion is extremely rare although some cases have been reported (see Peru & Pinna, 1997).
Now of these three forms of neglect I believe it is quite likely that my dog Barley is suffering from extrapersonal neglect following some sort of damage to her Posterior Parietal Cortex in her right hemisphere. The photographs below show my reasons for thinking this is likely. (Thanks go to my Mom for taking these photographs and emailing them to me!)
Number One. Bowl still relatively full of food.
Number Two. Barley eating her food.
Number Three. Barley thinks she has finished eating.
It is pretty clear from these images that she’s really neglecting to ‘see’ the food that is in her left visual field! If mom turns the bowl around so that the food is then on the right hand side of the bowl she continues to eat, albeit a little confused as to where this food has magically appeared from but still.
I hope that these images and experiences of Barleymow have helped illustrate this neurological disorder well, and I will keep tracks on how Barley is doing over time and write about anything new or interesting that happens.