Neglect is the one most fascinating neuropsychological syndrome that is both hard to define and very easy to recognize. To clarify some of the points made in the recent literature and reject some myths we discuss the theory, examination, localization and therapy of Neglect.
Here are some take home messages:
- Extinction and Neglect are different. They often occur together and extinction can but need not be a part of Neglect – i.e. there are cases of one without the other.
- Extinction and Anosognosia are different. Ditto.
- Like language on the left the bermuda triangle of Neglect is situated around the Sylvian fissure and comprises some frontal, parietal and temporal regions that are highly interconnected and also project to deeper structures such as the basal ganglia.
- The more parietal regions are probably responsible for the more externally oriented part of Neglect, the more temporal have to do with interoceptive and auditive functions and the frontal has to do with motor neglect, roughly similar to the respective regions on the left side for language [this is debated, but – what the heck – this is what I concluded].
- The line bisection tool might not be good for a screening instrument, being neither sensitive nor specific – hemianopia can completely obscur the result. There are also other situations in which line bisection is pathological without neglect. Still this is a much researched subject.
So how do you recognize Neglect? Watch your patient, speak with him, have him perform some basic tasks, describe objects. It is essential that cueing can temporarily remedy Neglect-driven defects – e.g. reminding a patient to look on the left side might help him recognize stimuli on the left for some seconds.
- Karnath. The anatomy of spatial neglect. Neuropsychologia 2011
- Vossel. Neurobiology of Neglect: Implications for New Therapeutic Strategies. Fortschr Neurol Psychiatr 2010