Dysexecutive syndrome

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Dysexecutive syndrome (DES) consists of a group of symptoms, [1] usually resulting from brain damage, that fall into cognitive, behavioural and emotional categories and tend to occur together. The term was introduced by Alan Baddeley [2] [3] 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. [2] 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. [2] [3] [4]

Contents

Symptoms and signs

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. [2] 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.[ citation needed ]

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.[ citation needed ]

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. [5] An individual that has DES may have a short attention span due to impairment in attentional control. [2] This may alter the individual's ability to focus, and as such have difficulty with reading and following a storyline or conversation. [5] 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. [5]

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. [5] Individuals with DES may experience confabulation, which is the spontaneous reporting of events that never happened. This can affect their autobiographical memory. [3] It is thought that patients may not be able to assess the accuracy of memory retrieval and therefore elaborate on implausible memories. [6]

Individuals with dementia, delirium or other severe psychiatric illnesses combined with DES often have disturbed sleep patterns. [5] Some will not recognize that it is night-time and may become upset when someone tries to correct them. [5]

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. [5]

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. [5] 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. [5] This can lead to higher levels of aggression and anger. DES can also cause patients to appear self-centered and stubborn. [5]

Utilization behaviour is when a patient automatically uses an object in the appropriate manner, but at an inappropriate time. [7] 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. [7]

Perseveration is also often seen in patients with DES. Perseveration is the repetition of thoughts, behaviours, or actions after they have already been completed. [8] 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. [8] 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.[ citation needed ]

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. [4] [9] 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. [4] 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. [2] 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's syndrome) can lead to a mild form of DES according to results of BADS. [10]

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 [6] or other internal trauma.

It is important to note that 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 (such as ventral tegmental area, basal ganglia and thalamus). [11] There is not one specific pattern of damage that leads to DES, as multiple affected brain structures and locations have led to the symptoms. [2] 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. [2] 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. [12] 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: [2]
  • 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.

The Dysexecutive Questionnaire (DEX) is a 20-item questionnaire designed to sample emotional, motivational, behavioural and cognitive changes in a subject with DES. [2] One version is designed for the subject to complete and another version is designed for someone who is close to the individual, such as a relative or caregiver. [2] [13] Instructions are given to the participant to read 20 statements describing common problems of everyday life and to rate them according to their personal experience. Each item is scored on a 5-point scale according to its frequency from never (0 point) to very often (4 points). [14]

Treatment

There is no cure for individuals with DES, but there are therapies to help them cope with their symptoms. DES can affect a number of functions in the brain and vary from person to person. Because of this variance, it is suggested that the most successful therapy would include multiple methods. [15] Researchers suggest that a number of factors in the executive functioning need to be improved, including self-awareness, goal setting, planning, self-initiation, self-monitoring, self-inhibition, flexibility, and strategic behaviour.

One method for individuals to improve in these areas is to help them plan and carry out actions and intentions through a series of goals and sub-goals. To accomplish this, therapists teach patients a three-step model called the General Planning Approach. [15] The first step is Information and Awareness, in which the patients are taught about their own problems and shown how this affects their lives. The patients are then taught to monitor their executive functions and begin to evaluate them. The second stage, Goal Setting and Planning, consists of patients making specific goals, as well as devising a plan to accomplish them. For example, patients may decide they will have lunch with a friend (their goal). They are taught to write down which friend it may be, where they are going for lunch, what time they are going, how they will get there, etc. (sub-goals). They are also taught to make sure the steps go in the correct order. The final stage, named Initiation, Execution, and Regulation, requires patients to implement their goals in their everyday lives. [15] Initiation can be taught through normal routines. The first step can cue the patient to go to the next step in their plan. Execution and regulation are put into action with reminders of how to proceed if something goes wrong in the behavioural script. This treatment method has resulted in improved daily executive functioning, however no improvements were seen on formal executive functioning tests.

Since planning is needed in many activities, different techniques have been used to improve this deficit in patients with DES. Autobiographical memories can be used to help direct future behaviour. [16] You can draw on past experiences to know what to do in the future. For example, when you want to take a bus, you know from past experience that you have to walk to the bus stop, have the exact amount of change, put the change in the slot, and then you can go find a seat. Patients with DES seem to not be able to use this autobiographical memory as well as a normal person. Training for DES patients asks them to think of a specific time when they did an activity previously. They are then instructed to think about how they accomplished this activity. An example includes "how would you plan a holiday". Patients are taught to think of specific times they went on a holiday and then to think how they may have planned these holidays. [16] By drawing on past experiences patients were better able to make good decisions and plans.

Cognitive Analytic Therapy (CAT) has also been used to help those with DES. Because individuals with this syndrome have trouble integrating information into their actions it is often suggested that they have programmed reminders delivered to a cell phone or pager. [17] This helps them remember how they should behave and discontinue inappropriate actions. Another method of reminding is to have patients write a letter to themselves. They can then read the letter whenever they need to. To help patients remember how to behave, they may also create a diagram. The diagram helps organize their thoughts and shows the patient how they can change their behaviour in everyday situations. [17]

The use of auditory stimuli has been examined in the treatment of DES. The presentation of auditory stimuli causes an interruption in current activity, which appears to aid in preventing "goal neglect" by increasing the patients' ability to monitor time and focus on goals. Given such stimuli, subjects no longer performed below their age group average IQ. [18]

Controversy

Some researchers have suggested that DES is mislabelled as a syndrome because it is possible for the symptoms to exist on their own. [19] Also, there is not a distinct pattern of damage that leads to the syndrome. Not all patients with frontal lobe damage have DES and some patients with no damage at all to the frontal lobe exhibit the necessary pattern of symptoms. [11] This has led research to investigate the possibility that executive functioning is broken down into multiple processes that are spread throughout the frontal lobe. [6] Further disagreement comes from the syndrome being based on Baddeley and Hitch's model of working memory and the central executive, which is a hypothetical construct. [2]

The vagueness of some aspects of the syndrome has led researchers to test for it in a non-clinical sample. The results show that some dysexecutive behaviours are part of everyday life, and the symptoms exist to varying degrees in everyone. [20] For example, absent-mindedness and lapses in attention are common everyday occurrences for most people. However, for the majority of the population such inattentiveness is manageable, whereas patients with DES experience it to such a degree that daily tasks become difficult.

See also

Related Research Articles

Source amnesia is the inability to remember where, when or how previously learned information has been acquired, while retaining the factual knowledge. This branch of amnesia is associated with the malfunctioning of one's explicit memory. It is likely that the disconnect between having the knowledge and remembering the context in which the knowledge was acquired is due to a dissociation between semantic and episodic memory – an individual retains the semantic knowledge, but lacks the episodic knowledge to indicate the context in which the knowledge was gained.

The Fregoli delusion is a rare disorder in which a person holds a delusional belief that different people are in fact a single person who changes appearance or is in disguise. The syndrome may be related to a brain lesion and is often of a paranoid nature, with the delusional person believing themselves persecuted by the person they believe is in disguise.

<span class="mw-page-title-main">Temporal lobe</span> One of the four lobes of the mammalian brain

The temporal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain.

<span class="mw-page-title-main">Frontal lobe</span> Part of the brain

The frontal lobe is the largest of the four major lobes of the brain in mammals, and is located at the front of each cerebral hemisphere. It is parted from the parietal lobe by a groove between tissues called the central sulcus and from the temporal lobe by a deeper groove called the lateral sulcus. The most anterior rounded part of the frontal lobe is known as the frontal pole, one of the three poles of the cerebrum.

Amotivational syndrome is a chronic psychiatric disorder characterized by signs that are linked to cognitive and emotional states such as detachment, blunted emotion and drives, executive functions like memory and attention, disinterest, passivity, apathy, and a general lack of motivation. This syndrome can be branched into two subtypes - marijuana amotivational syndrome, interchangeably known as cannabis induced amotivational syndrome which is caused by usage and/or dependency of the substance and is primarily associated with long-term effects of cannabis use, and SSRI-induced amotivational syndrome or SSRI-induced apathy caused by the intake of SSRI medication dosage. According to the Handbook of Clinical Psychopharmacology for Therapists, amotivational syndrome is listed as a possible side effect of SSRIs in the treatment of clinical depression.

The mental status examination (MSE) is an important part of the clinical assessment process in neurological and psychiatric practice. It is a structured way of observing and describing a patient's psychological functioning at a given point in time, under the domains of appearance, attitude, behavior, mood and affect, speech, thought process, thought content, perception, cognition, insight, and judgment. There are some minor variations in the subdivision of the MSE and the sequence and names of MSE domains.

Acalculia is an acquired impairment in which people have difficulty performing simple mathematical tasks, such as adding, subtracting, multiplying, and even simply stating which of two numbers is larger. Acalculia is distinguished from dyscalculia in that acalculia is acquired late in life due to neurological injury such as stroke, while dyscalculia is a specific developmental disorder first observed during the acquisition of mathematical knowledge. The name comes from the Greek a- meaning "not" and Latin calculare, which means "to count".

Memory disorders are the result of damage to neuroanatomical structures that hinders the storage, retention and recollection of memories. Memory disorders can be progressive, including Alzheimer's disease, or they can be immediate including disorders resulting from head injury.

<span class="mw-page-title-main">Frontal lobe disorder</span> Brain disorder

Frontal lobe disorder, also frontal lobe syndrome, is an impairment of the frontal lobe of the brain due to disease or frontal lobe injury. The frontal lobe plays a key role in executive functions such as motivation, planning, social behaviour, and speech production. Frontal lobe syndrome can be caused by a range of conditions including head trauma, tumours, neurodegenerative diseases, neurodevelopmental disorders, neurosurgery and cerebrovascular disease. Frontal lobe impairment can be detected by recognition of typical signs and symptoms, use of simple screening tests, and specialist neurological testing.

Perseveration, in the fields of psychology, psychiatry, and speech-language pathology, is the repetition of a particular response regardless of the absence or cessation of a stimulus. It is usually caused by a brain injury or other organic disorder. Symptoms include "lacking ability to transition or switch ideas appropriately with the social context, as evidenced by the repetition of words or gestures after they have ceased to be socially relevant or appropriate", or the "act or task of doing so", and are not better described as stereotypy.

Alcohol-related dementia (ARD) is a form of dementia caused by long-term, excessive consumption of alcoholic beverages, resulting in neurological damage and impaired cognitive function.

<span class="mw-page-title-main">Frontal lobe injury</span> Type of brain injury

The frontal lobe of the human brain is both relatively large in mass and less restricted in movement than the posterior portion of the brain. It is a component of the cerebral system, which supports goal directed behavior. This lobe is often cited as the part of the brain responsible for the ability to decide between good and bad choices, as well as recognize the consequences of different actions. Because of its location in the anterior part of the head, the frontal lobe is arguably more susceptible to injuries. Following a frontal lobe injury, an individual's abilities to make good choices and recognize consequences are often impaired. Memory impairment is another common effect associated with frontal lobe injuries, but this effect is less documented and may or may not be the result of flawed testing. Damage to the frontal lobe can cause increased irritability, which may include a change in mood and an inability to regulate behavior. Particularly, an injury of the frontal lobe could lead to deficits in executive function, such as anticipation, goal selection, planning, initiation, sequencing, monitoring, and self-correction. A widely reported case of frontal lobe injury was that of Phineas Gage, a railroad worker whose left frontal lobe was damaged by a large iron rod in 1848.

Retrospective memory is the memory of people, words, and events encountered or experienced in the past. It includes all other types of memory including episodic, semantic and procedural. It can be either implicit or explicit. In contrast, prospective memory involves remembering something or remembering to do something after a delay, such as buying groceries on the way home from work. However, it is very closely linked to retrospective memory, since certain aspects of retrospective memory are required for prospective memory.

In psychology and neuroscience, executive dysfunction, or executive function deficit, is a disruption to the efficacy of the executive functions, which is a group of cognitive processes that regulate, control, and manage other cognitive processes. Executive dysfunction can refer to both neurocognitive deficits and behavioural symptoms. It is implicated in numerous psychopathologies and mental disorders, as well as short-term and long-term changes in non-clinical executive control.

In psychology, confabulation is a memory error consisting of the production of fabricated, distorted, or misinterpreted memories about oneself or the world. It is generally associated with certain types of brain damage or a specific subset of dementias. While still an area of ongoing research, the basal forebrain is implicated in the phenomenon of confabulation. People who confabulate present with incorrect memories ranging from subtle inaccuracies to surreal fabrications, and may include confusion or distortion in the temporal framing of memories. In general, they are very confident about their recollections, even when challenged with contradictory evidence.

<span class="mw-page-title-main">Attentional control</span> Individuals capacity to choose what they pay attention to and what they ignore

Attentional control, colloquially referred to as concentration, refers to an individual's capacity to choose what they pay attention to and what they ignore. It is also known as endogenous attention or executive attention. In lay terms, attentional control can be described as an individual's ability to concentrate. Primarily mediated by the frontal areas of the brain including the anterior cingulate cortex, attentional control is thought to be closely related to other executive functions such as working memory.

Cerebellar cognitive affective syndrome (CCAS), also called Schmahmann's syndrome is a condition that follows from lesions (damage) to the cerebellum of the brain. It refers to a constellation of deficits in the cognitive domains of executive function, spatial cognition, language, and affect resulting from damage to the cerebellum. Impairments of executive function include problems with planning, set-shifting, abstract reasoning, verbal fluency, and working memory, and there is often perseveration, distractibility and inattention. Language problems include dysprosodia, agrammatism and mild anomia. Deficits in spatial cognition produce visual–spatial disorganization and impaired visual–spatial memory. Personality changes manifest as blunting of affect or disinhibited and inappropriate behavior. These cognitive impairments result in an overall lowering of intellectual function. CCAS challenges the traditional view of the cerebellum being responsible solely for regulation of motor functions. It is now thought that the cerebellum is responsible for monitoring both motor and nonmotor functions. The nonmotor deficits described in CCAS are believed to be caused by dysfunction in cerebellar connections to the cerebral cortex and limbic system.

Executive functions are a cognitive apparatus that controls and manages cognitive processes. Norman and Shallice (1980) proposed a model on executive functioning of attentional control that specifies how thought and action schemata become activated or suppressed for routine and non-routine circumstances. Schemas, or scripts, specify an individual's series of actions or thoughts under the influence of environmental conditions. Every stimulus condition turns on the activation of a response or schema. The initiation of appropriate schema under routine, well-learned situations is monitored by contention scheduling which laterally inhibits competing schemas for the control of cognitive apparatus. Under unique, non-routine procedures controls schema activation. The SAS is an executive monitoring system that oversees and controls contention scheduling by influencing schema activation probabilities and allowing for general strategies to be applied to novel problems or situations during automatic attentional processes.

Time-based prospective memory is a type of prospective memory in which remembrance is triggered by a time-related cue that indicates that a given action needs to be performed. An example is remembering to watch a television program at 3 p.m. In contrast to time-based prospective memory, event-based prospective memory is triggered by an environmental cue that indicates that an action needs to be performed. An example is remembering to send a letter after seeing a mailbox. While event-based memory is dependent on the environment, time-based prospective memory is self-initiated; one must specifically monitor the passage of time.

Semantic amnesia is a type of amnesia that affects semantic memory and is primarily manifested through difficulties with language use and acquisition, recall of facts and general knowledge. A patient with semantic amnesia would have damage to the temporal lobe.

References

  1. ↑ Halligan, P.W., Kischka, U., & Marshall, J.C. (2004). Handbook of clinical neuropsychology. Oxford University Press.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 Wilson, 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.
  3. 1 2 3 Baddeley, A., & Wilson, B. (1988). "Frontal amnesia and the dysexecutive syndrome." Brain and Cognition, 7, 212–230.
  4. 1 2 3 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.
  5. 1 2 3 4 5 6 7 8 9 10 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
  6. 1 2 3 Papagno, C., & Baddeley, A. (1997). "Confabulation in dysexecutive patient: implication for models of retrieval." Cortex, 33, 743–752.
  7. 1 2 Baxter, Doreen, M., Burgess, Paul, W., Schon, Frederick, & Shallice, Tim. (1989). "The origins of utilization behaviour." Brain, 112, 1587–1598.
  8. 1 2 Albert, Martin L. & Sandson, Jennifer. (1984). "Varieties of perseveration." Neuropsychologia, 22(6), 715–732.
  9. ↑ 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.
  10. ↑ 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.
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  12. ↑ 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.
  13. ↑ Norris, G., & Tate, R. (2000). "The behavioural assessment of the dysexecutive syndrome (BADS): ecological, concurrent and construct validity." Neuropsychological Rehabilitation, 10, 33–45.
  14. ↑ Amieva, H., Phillips, L., & Della Sala, S. (2003). "Behavioural dysexecutive symptoms in normal aging." Brain and Cognition, 53, 129–132.
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  16. 1 2 Dritschel, B., Evans, J. J., Hewitt, J. (2006). "Theory driven rehabilitation of executive functioning: Improving planning skills in people with traumatic brain injury through the use of an autobiographical episodic memory cueing procedure." Neuropsychologia, 44, 1468–1474.
  17. 1 2 Gracey, F., Hamill, M., Mohamed, S., Psaila, K., O'Dell, J., Sutton, L., et al.(2008). "Dysexecutive problems and interpersonal relating following frontal brain injury: Reformulation and compensation in cognitive analytic therapy (CAT)." Neuro-Psychoanalysis, 10(1), 43-58
  18. ↑ Manly T, Hawkins K, Evans J, Woldt K, Robertson IH (2002). "Rehabilitation of executive function: facilitation of effective goal management on complex tasks using periodic auditory alerts." Neuropsychologia, 40(3):271–81
  19. ↑ 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.
  20. ↑ Chan, C.K. (2001). "Dysexecutive symptoms among a non-clinical sample: a case study with the use of the dysexecutive questionnaire." British Journal of Psychology, 92, 551–565.
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