Aboulia

Aboulia or Abulia (from the Greek "αβουλία", meaning "non-will"), in neurology, refers to a lack of will or initiative and is one of the Disorders of Diminished Motivation or DDM. Aboulia falls in the middle of the spectrum of diminished motivation, with apathy being less extreme and akinetic mutism being more extreme than aboulia. A patient with aboulia is unable to act or make decisions independently. It may range in severity from subtle to overwhelming. It is also known as Blocq's disease (which also refers to abasia and astasia-abasia). Abulia was originally considered to be a disorder of the will.

Symptoms and signs

Aboulia has been known to clinicians since 1838. However, in the time since its inception, the definition of aboulia has been subjected to many different forms, some even contradictory with previous ones. Aboulia has been described as a loss of drive, expression, loss of behavior and speech output, slowing and prolonged speech latency, and reduction of spontaneous thought content and initiative. The clinical features most commonly associated with aboulia are:

• Difficulty in initiating and sustaining purposeful movements
• Lack of spontaneous movement
• Reduced spontaneous movement
• Increased response-time to queries
• Passivity
• Reduced emotional responsiveness and spontaneity
• Reduced social interactions
• Reduced interest in usual pastimes

Especially in patients with progressive dementia, it may affect feeding. Patients may continue to chew or hold food in their mouths for hours without swallowing it. The behavior may be most evident after these patients have eaten part of their meals and no longer have strong appetites. Caregivers can use sweet or salty flavored foods later in meals to provide interest and increase oral intake, but must always clear the mouth of food after each meal.

Differentiation from other disorders

Both neurologists and psychiatrists recognize aboulia to be a distinct clinical entity, but its status as a syndrome is unclear. Although aboulia has been known to clinicians since 1838, it has been subjected to different interpretations - from 'a pure lack of will', in the absence of motor paralysis to, more recently, being considered 'a reduction in action emotion and cognition'. As a result of the changing definition of aboulia, there is currently a debate on whether or not aboulia is a sign or a symptom of another disease, or its own disease that seems to appear in the presence of other more well-researched diseases, such as Alzheimer's disease.

A survey of 2 movement disorder experts, 2 neuropsychiatrists, and 2 rehabilitation experts was conducted and the results did not seem to shed any light on the matter of differentiating aboulia from other DDMs. The experts used the terms apathy and aboulia interchangeably and even debated on whether or not aboulia was a discrete entity, or just a hazy gray area on a spectrum of more defined disorders. Four of the experts said aboulia was a sign and a symptom, but the group was split on whether or not it was a syndrome. Another survey, which consisted of true and false questions about what aboulia is distinct from, whether it is a sign, symptom, or syndrome, where lesions are present in cases of aboulia, what diseases are commonly associated with aboulia, and what current treatments are used for aboulia, was sent to 15 neurologists and 10 psychiatrists. Most experts agreed that aboulia is clinically distinct from depression, akinetic mutism, and alexithymia. However, only 32% believed aboulia was different from apathy, while 44% said they were different, and 24% were unsure. Yet again, there was disagreement about whether or not aboulia is a sign, symptom, or syndrome.

The study of motivation has been mostly about how stimuli come to acquire significance for animals. Only recently has the study of motivational processes been extended to integrate biological drives and emotional states in the explanation of purposeful behaviour in human beings. Considering the number of disorders attributed to a lack of will and motivation, it is essential that aboulia and apathy be defined more precisely to avoid confusion.

Causes

Many different causes of aboulia have been suggested. While there is some debate about the validity of aboulia as a separate disease, experts mostly agree that aboulia is the result of frontal lesions and not with cerebellar or brainstem lesions. As a result of more and more evidence showing that the mesolimbic and the mesocortical dopamine system are key to motivation and responsiveness to reward, aboulia may be a dopamine-related dysfunction. Aboulia may also result from a variety of brain injuries which cause personality change, such as dementing illnesses, trauma, or intracerebral hemorrhage (stroke), especially stroke causing diffuse injury to the right hemisphere..

Damage to the basal ganglia

Injuries to the frontal lobe and/or the basal ganglia can interfere with an individual's ability to initiate speech, movement, and social interaction. Studies have shown that 5-67% of all patients with traumatic brain injuries and 13% of patients with lesions on their basal ganglia suffer from some form of diminished motivation. Abulia has also been associated with amphetamine withdrawal. It may complicate rehabilitation when a stroke patient is uninterested in performing tasks like walking despite being capable of doing so. It should be differentiated from apraxia, when a brain injured patient has impairment in comprehending the movements necessary to perform a motor task despite not having any paralysis that prevents performing the task; that condition can also result in lack of initiation of activity.

Damage to the capsular genu

A case study involving two patients who suffered from acute confusional state and aboulia was conducted to see if these symptoms were the result of an infarct in the capsular genu. Using clinical neuropsychological and MRI evaluations at baseline and one year later showed that the cognitive impairment was still there one year after the stroke. Cognitive and behavioral alterations due to a genu infarct are most likely because the thalamo-cortical projection fibers that originate from the ventral-anterior and medial-dorsal nuclei traverse the internal capsule genu. These tracts are part of a complex system of cortical and subcortical frontal circuits through which the flow of information from the entire cortex takes place before reaching the basal ganglia. Cognitive deterioration could have occurred through the genu infarcts affecting the inferior and anterior thalamic peduncles. The interesting thing about this case study was that the patients did not show any functional deficit at the follow-up one year after the stroke and were not depressed but did show diminished motivation. This result supports the idea that aboulia may exist independently of depression as its own syndrome.

Damage to anterior cingulate circuit

The anterior cingulate circuit consists of the anterior cingulate cortex, also referred to as Brodmann's area 24. and its projections to the ventral striatum which includes the ventromedial caudate. The loop continues to connect to the ventral pallidum, which connects to the vental anterior nucleus of the thalamus. This circuit is essential for the initiation of behavior, motivation and goal orientation, which are the very things missing from a patient with a disorder of diminished motivation. Unilateral injury or injury along any point in the circuit leads to aboulia regardless of the side of the injury, but if there is bilateral damage, the patient will exhibit a more extreme case of diminished motivation, akinetic mutism.

Acute caudate vascular lesions

It is well documented that the caudate nucleus is involved in degenerative diseases of the central nervous system such as Huntington disease. In a case study of 32 acute caudate stroke patients, 48% were found to be experiencing aboulia. Most of the cases where aboulia was present were when the patients had a left caudate infarct that extended into the putamen as seen through a CT or MRI scan.

Diagnosis

Diagnosis for aboulia can be quite difficult because it falls between two other disorders of diminished motivation, and one could easily see an extreme case of aboulia as akinetic mutism or a lesser case of aboulia as apathy and therefore, not treat the patient appropriately. If it were to be confused with apathy, it might lead to attempts involve the patient with physical rehabilitation or other interventions where a source of strong motivation would be necessary to succeed but would still be absent. The best way to diagnose aboulia is through clinical observation of the patient as well as questioning of close relatives and loved ones to give the doctor a frame of reference with which they can compare the patient's new behavior to see if there is in fact a case of diminished motivation. In recent years, imaging studies using a CT or MRI scan have been shown to be quite helpful in localizing brain lesions which have been shown to be one of the main causes of aboulia.

Illnesses where aboulia may be present

• Depression
• Schizophrenia
• Parkinson's Disease
• Huntington's Disease
• Progressive supranuclear palsy
• Traumatic Brain Injury
• Stroke

Alzheimer's Disease

A lack of motivation has been reported in 25%-50% of patients with Alzheimer's Disease. While depression is also common in patients with this disease, aboulia is not a mere symptom of depressions because more than half of the patients with Alzheimer's disease with aboulia do not suffer from depression. Several studies have shown that aboulia is most prevalent in cases of severe dementia which may result from reduced metabolic activity in the prefontal regions of the brain. Patients with Alzheimer's disease and aboulia are significantly older than patients with Alzheimer's who do not lack motivation. Going along with that, the prevalence of aboulia increased from 14% in patients with a mild case Alzheimer's disease to 61% in patients with a severe case of Alzheimer's disease, which most likely developed over time as the patient got older.

Current treatment

Most current treatments for aboulia are pharmacological, including the use of antidepressants . However, antidepressant treatment is not always successful and have opened up the door for alternative methods of treatment. The first step to successful treatment of aboulia, or any other DDM, is a preliminary evaluation of the patient's general medical condition and fixing the problems that can be fixed easily. This may mean controlling seizures or headaches, arranging physical or cognitive rehabilitation for cognitive and sensorimotor loss, or ensuring optimal hearing, vision, and speech. These elementary steps also increase motivation because improved physical status may enhance functional capacity, drive, and energy and thereby increase the patient's expectation that initiative and effort will be successful.

There are 5 steps to pharmacological treatment:

1. Optimize medical status
2. Diagnose and treat other conditions more specifically associated with diminished motivation (e.g., apathetic hyperthyroidism, Parkinson's disease).
3. Eliminate or reduce doses of psychotropics and other agents that aggravate motivational loss (e.g., SSRIs, dopamine antagonists).
4. Treat depression efficaciously when both DDM and depression are present.
5. Increase motivation through use of stimulants, dopamine agonists, or other agents such as cholinesterase inhibitors

References

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