Dysexecutive syndrome

The Dysexecutive Syndrome is a term for numerous cognitive, emotional & behavioural symptoms which tend to occur comorbidly following a brain injury to the frontal lobes, or more specifically to specific prefrontal cortex areas. Dysexecutive Syndrome is generally considered to be a dysfunction of the Executive system or Executive functions. The determined localisation of these cognitive functions within prefrontal cortex regions is due mainly to studies of patients with damage to these areas, although there is also increasing evidence from fMRI studies.

Definition

The Dysexecutive Syndrome consists of a number of symptoms [Halligan P.W, Kischka U. & Marshall J.C. (2004) Handbook of Clinical Neuropsychology. Oxford University Press, 2004.] which tend to occur together (hence it being described as a syndrome). Broadly speaking, these symptoms fall into three main categories; Cognitive, Emotional & Behavioural. Although many of these symptoms regularly co-occur, it is common to encounter patients who have several, but not all of these symptoms. This is one reason why some researchers are beginning to argue that the Dysexecutive Syndrome is not the best term to describe these various symptoms (see criticisms below).

Cognitive Symptoms

* Short attention span
* Poor working memory
* Poor short term memory
* Difficulty in planning & reasoning
* Environmental dependence syndrome

Emotional Symptoms

* Difficulty in inhibiting emotions, anger, excitement, sadness etc...
* Depression, possibly due to above.
* Occasionally, difficulty in understanding others' points of view, leading to anger & frustration.

Behavioural Symptoms

* Utilization behavior
* Perseveration behaviour
* Inappropriate aggression
* Inappropriate sexual behaviour
* Inappropriate humour & telling of pointless & boring stories (Witzelsucht)

Criticisms

The fact that many of the Dysexecutive Syndrome symptoms can occur alone has led some researchers [Stuss, D.T. & Alexander, M.P. (2007) Is there a Dysexecutive Syndrome? Philosophical transactions of the Royal Society of London. Series B, Biological Sciences, 362 (1481), 901-15.] to suggest that the symptoms should not be labelled as a "syndrome" as such. Some of the latest imaging research [ Gilbert, S.J. & Burgess, P.W. (2008). Executive Function. Current Biology, Vol.18, No. 3, 110 - 114.] on frontal cortex areas suggests that Executive Functions may be more discrete than was previously thought. The argument is that rather than damage to the frontal cortex areas causing Dysexecutive Function in general, that damage to multiple frontal cortex areas that are close together (but responsible for different cognitive functions) can cause the various symptoms of the Dysexecutive Syndrome.

The counterargument is that there is a Central Executive corresponding to areas within the frontal lobes which is responsible for much of the Executive system and Executive function in general, and that damage to this area causes the Dysexecutive syndrome.

Frequently-cited case(?)

Phineas Gage, who suffered a severe frontal lobe injury in 1848, has been called a case of Dysexecutive Syndrome. But Gage's psychological changes are typically grossly exaggerated: of the symptoms listed above, the only ones Gage can even "arguably" be said to have exhibited (based on primary sources) are "anger and frustration," slight memory impairment, and "difficulty in planning."

In particular, the primary sources do not report utilization behavior, depression, aggression, inappropriate sexual behavior, or "inappropriate humour and telling of pointless and boring stories" (in fact, his audience was said to have found his stories entertaining). The oft-quoted statement by friends -- that after the accident he was "no longer Gage" -- admits interpretation as any number of behavioral or personality changes, not even necessarily of organic etiology. After his initial recovery, he was socially functional and self-supporting for the remainder of his life.

ee also

* executive functions
* executive system
* attention
* cognitive neuropsychology
* frontal lobe
* working memory
* Phineas Gage

External links

* [http://www.neuro.spc.org/vaughan/ExecutiveFunctionLecture.pdf Notes on dysexecutive syndrome and the executive system]

References