Dysexecutive syndrome (DES) consists of a group of symptoms,Halligan, P.W., Kischka, U., & Marshall, J.C. (2004). Handbook of clinical neuropsychology. Oxford University Press. usually resulting from brain damage, that fall into cognitive, behavioural and emotional categories and tend to occur together. The term was introduced by Alan BaddeleyWilson, B.A., Evans, J.J., Emslie, H., Alderman, N., & Burgess, P. (1998). "The development of an ecologically valid test for assessing patients with a dysexecutive syndrome." Neuropsychological Rehabilitation, 8, 213–228.Baddeley, A., & Wilson, B. (1988). "Frontal amnesia and the dysexecutive syndrome." Brain and Cognition, 7, 212–230. to describe a common pattern of dysfunction in executive functions, such as planning, abstract thinking, flexibility and behavioural control. It is thought to be Baddeley's hypothesized working memory system and the central executive that are the hypothetical systems impaired in DES. The syndrome was once known as frontal lobe syndrome; however 'dysexecutive syndrome' is preferred because it emphasizes the functional pattern of deficits (the symptoms) over the location of the syndrome in the frontal lobe, which is often not the only area affected.Katz, N., Tadmor, I., Felzen, B., & Hartman-Maeir, A. (2007). "The behavioural assessment of the dysexecutive syndrome (BADS) in schizophrenia and its relation to functional outcomes." Neuropsychological Rehabilitation, 17, 192–205.
Signs and symptoms Symptoms of DES fall into three broad categories: cognitive, emotional and behavioural. Many of the symptoms can be seen as a direct result of impairment to the central executive component of working memory, which is responsible for attentional control and inhibition. Although many of the symptoms regularly co-occur, it is common to encounter patients who have several, but not all symptoms. The accumulated effects of the symptoms have a large impact on daily life.
Cognitive symptoms Cognitive symptoms refer to a person's ability to process thoughts. Cognition primarily refers to memory, the ability to learn new information, speech, and reading comprehension. Deficits within this area cause many problems with everyday life decisions.
One of the main difficulties for an individual with DES is planning and reasoning. Impaired planning and reasoning affect the individual's ability to realistically assess and manage the problems of everyday living. New problems and situations may be especially poorly handled because of the inability to transfer previous knowledge to the new event. An individual that has DES may have a short attention span due to impairment in attentional control. This may alter the individual's ability to focus, and as such have difficulty with reading and following a storyline or conversation. For instance, they can easily lose track of conversations which can make it difficult to hold a meaningful conversation and may result in avoiding social interactions.Tina Thornton, Ed. (2008) Dysexecutive syndrome: dealing with day-to-day decision-making., Aged Services, Royal Hobart Hospital, Tasmanian Department of Health and Human Services, Australia. Retrieved March 11, 2011 from
Individuals with DES will have very poor working memory and short term memory due to executive dysfunction. The dysfunction can range from mild and subtle to severe and obvious. There is a tremendous variability in the manifestations of executive dysfunction with strong influences often apparent from the affected person's personality, life experiences and intellect. Individuals with DES may experience confabulation, which is the spontaneous reporting of events that never happened. This can affect their autobiographical memory. It is thought that patients may not be able to assess the accuracy of memory retrieval and therefore elaborate on implausible memories.
Individuals with dementia, delirium or other severe psychiatric illnesses combined with DES often have disturbed sleep patterns. Some will not recognize that it is night-time and may become upset when someone tries to correct them.
Emotional symptoms The emotional symptoms that individuals with DES experience may be quite extreme and can cause extensive problems. They may have difficulty inhibiting many types of emotions such as anger, excitement, sadness, or frustration. Due to multiple impairments of cognitive functioning, there can be much more frustration when expressing certain feelings and understanding how to interpret everyday situations. Individuals with DES may have higher levels of aggression or anger because they lack abilities that are related to behavioural control. They can also have difficulty understanding others' points of view, which can lead to anger and frustration.
Behavioural symptoms Behavioural symptoms are evident through an individual's actions. People with DES often lose their social skills because their judgments and insights into what others may be thinking are impaired. They may have trouble knowing how to behave in group situations and may not know how to follow social norms. The central executive helps control impulses; therefore when impaired, patients have poor impulse control. This can lead to higher levels of aggression and anger. DES can also cause patients to appear self-centered and stubborn.
Utilization behaviour is when a patient automatically uses an object in the appropriate manner, but at an inappropriate time.Baxter, Doreen, M., Burgess, Paul, W., Schon, Frederick, & Shallice, Tim. (1989). "The origins of utilization behaviour." Brain, 112, 1587–1598. For example, if a pen and paper are placed in front of an individual with DES they will start to write or if there is a deck of cards they will deal them out. Patients showing this symptom will begin the behaviour in the middle of conversations or during auditory tests. Utilization behaviour is thought to occur because an action is initiated when an object is seen, but patients with DES lack the central executive control to inhibit acting it out at inappropriate times.
Perseveration is also often seen in patients with DES. Perseveration is the repetition of thoughts, behaviours, or actions after they have already been completed.Albert, Martin L. & Sandson, Jennifer. (1984). "Varieties of perseveration." Neuropsychologia, 22(6), 715–732. For instance, continually blowing out a match, after it is no longer lit is an example of perseveration behaviour. There are three types of perseveration: continuous perseveration, stuck-in-set perseveration, and recurrent perseveration. Stuck-in-set perseveration is most often seen in dysexecutive syndrome. This type of perseveration refers to when a patient cannot get out of a specific frame of mind, such as when asked to name animals they can only name one. If you ask them to then name colours, they may still give you animals. Perseveration may explain why some patients appear to have obsessive–compulsive disorder.
Comorbid disorders DES often occurs with other disorders, which is known as comorbidity. Many studies have examined the presence of DES in patients with schizophrenia. Results of schizophrenic patients on the Behavioural Assessment of the Dysexecutive Syndrome (BADS) test (discussed below) are comparable to brain injured patients.Evans, J.J., Chua, S.E., McKenna, P.J., & Wilson, B.A. (1997). "Assessment of the dysexecutive syndrome in schizophrenia." Psychological Medicine, 27, 635–646. Further, results of BADS have been shown to correlate with phases of schizophrenia. Patients in the chronic phase of the disorder have significantly lower scores than those who are acute. This is logical due to the similarities in executive disruptions that make everyday life difficult for those with schizophrenia and symptoms that form DES.
Patients with Alzheimer's disease and other forms of dementia have been shown to exhibit impairment in executive functioning as well. The effects of DES symptoms on the executive functions and working memory, such as attentiveness, planning and remembering recently learned things, are some of the earliest indicators of Alzheimer's disease and dementia with Lewy bodies.
Studies have also indicated that chronic alcoholism (see Korsakoff syndrome) can lead to a mild form of DES according to results of BADS.Ihara, H., Berrios, G.E., & London, M. (2000). "Group and case study of the dysexecutive syndrome in alcoholism without amnesia." Journal of Neurology, Neurosurgery, and Psychiatry, 68, 731–737.
Causes
The most frequent cause of the syndrome is brain damage to the frontal lobe. Brain damage leading to the dysexecutive pattern of symptoms can result from physical trauma such as a blow to the head or a stroke Papagno, C., & Baddeley, A. (1997). "Confabulation in dysexecutive patient: implication for models of retrieval." Cortex, 33, 743–752. or other internal trauma.
Frontal lobe damage is not the only cause of the syndrome. It has been shown that damage, such as lesions, in other areas of the brain may indirectly affect executive functions and lead to similar symptoms (e.g., ventral tegmental area, basal ganglia and thalamus).Manchester, D., Priestley, N., & Jackson, H. (2004). "The assessment of executive functions: coming out of the office." Brain injury, 18, 1067–1081. There is not one specific pattern of damage that leads to DES, as multiple affected brain structures and locations have led to the symptoms. This is one reason why the term frontal lobe syndrome is not preferred.
Diagnosis Assessment of patients with DES can be difficult because traditional tests generally focus on one specific problem for a short period of time. People with DES can do fairly well on these tests because their problems are related to integrating individual skills into everyday tasks. The lack of everyday application of traditional tests is known as low ecological validity.
Behavioural The Behavioural Assessment of the Dysexecutive Syndrome (BADS) was designed to address the problems of traditional tests and evaluate the everyday problems arising from DES.Alderman, N., Burgess, P., Emslie, H., Evans, J., & Wilson, B. (2003). "Behavioural assessment of the dysexecutive syndrome (BADS)." Journal of Occupational Psychology, Employment and Disability, 5, 33–37. BADS is designed around six subtests and ends with the Dysexecutive Questionnaire (DEX). These tests assess executive functioning in more complex, real-life situations, which improves their ability to predict day-to-day difficulties of DES. The six tests are as follows: Rule Shift Cards – Assesses the subject's ability to ignore a prior rule after being given a new rule to follow. Action Program – This test requires the use of problem solving to accomplish a new, practical task. Key Search – This test reflects the real-life situation of needing to find something that has been lost. It assesses the patient's ability to plan how to accomplish the task and monitor their own progress. Temporal Judgment – Patients are asked to make estimated guesses to a series of questions such as, "how fast do racehorses gallop?". It tests the ability to make sensible guesses. Zoo Map – Tests the ability to plan while following a set of rules. Modified Six Elements – This test assesses the subject's ability to plan, organize and monitor behaviour.