Pure sensory syndrome occurs after a cerebral infarction in the thalamus , a structure of vital importance for filtering sensory information, and causes, among other symptoms, paralysis and a loss of sensation in half of the body.

In this article we explain what pure sensory syndrome is, what its main causes are, what symptoms it causes and what the treatment is.

What is pure sensory syndrome?

The pure sensory syndrome is one of the classic lacunar syndromes best defined by Charles M. Fisher , one of the first neurologists to study and contribute to the understanding of strokes, especially those related to carotid artery diseases and lacunar infarctions.

In clinical practice, lacunar syndrome is understood to be any clinical manifestation in which a lacunar-type cerebral infarction occurs.

This type of infarction is characterized by the presence of tiny lesions (not larger than 15 mm in diameter) caused by the occlusion of small branches of the perforating arteries of the brain.

Pure sensory syndrome makes up 7% of all lacunar infarctions and people who suffer it manifest persistent or transitory sensory symptoms, affecting half of the body.

Causes

Little is known about the frequency of the different forms of the syndrome , which include: complete hemisensory syndrome (with sensory involvement involving the entire face-brack-crural axis, that is, the face, arm and leg on one side of the body); and incomplete hemisensory syndrome (less specific and with different clinical variants).

The most common cause of pure sensory syndrome includes lacunar infarction in the thalamus, although it can also be secondary to intracerebral hemorrhages or cortical injury, of the internal, parietal, mesencephalic or pontine capsule (related to the bulge or bridge, a structure located at the base of the brain).

There is still not much information about the different types of lacunar infarctions that can cause pure sensory syndrome, as well as the differences between lacunar and non-lacunar strokes.

However, studies suggest that in 80-90% of cases, the cause of pure sensory syndrome is lacunar infarction ; and in the remaining 10% of cases, the causes would be varied, including atherothrombotic infarctions, primary intracerebral hemorrhages and other types of infarction of unknown etiology.

Symptoms

Pure sensory syndrome causes a series of sensory symptoms that usually affect the face, arm and leg on one side of the body (hemi-facial-brachial-crural hypesthesia).

Common symptoms include hypesthesia (reduced sensation) alone without motor involvement, paralysis of one side of the body or hemiplegia , dysarthria (difficulty articulating sounds and words), nystagmus (uncontrolled, involuntary eye movement) and visual or cognitive defects (impaired executive functions, such as semantic fluency or verbal short-term memory).

This lacunar syndrome can also be associated with a neuropathic type of pain , and epicritical sensitivity (which makes it possible to discriminate both the quality and the location of a sensory stimulus), protopathic sensitivity (opposite to epicritical) or both can be affected.

Other types of symptoms such as paresthesias (numbness and tingling in the body, mainly the extremities) are usually rare, as is isolated proprioceptive loss, which involves the ability to know the relative position of the body and muscles at all times.

The hypesthesia that occurs in pure sensory syndrome can be facio-brachial, facio-crural, facio-crural or trunk and crural, with frequent thalamic topography, and that which occurs in the fingers can be associated with parietal cortical lesions . Other patterns with this same symptom have also been associated with lesions in the trunk of the brain.

Treatment

One of the maxims when treating pure sensory syndrome and, in general, any type of lacunar infarction, is to intervene in time . This means that treatment must be urgent, as the first hours after the stroke are crucial, and a difference in hours may mean that the patient survives or not.

After the heart attack, the person should be taken as soon as possible to the nearest hospital to start treatment as soon as possible (within the first 3 hours after the injury), usually using anticoagulant drugs that remove the occlusion and allow the blood supply to flow normally again. Sometimes brain surgery is required, but this is not usual.

Once the operation has been performed, the patient will have to start a rehabilitation that includes visiting different professionals from various health branches .

Physiotherapy and medical follow-up

The role of the physiotherapist is to help the patient restore motor functions, mainly by performing exercises with the affected joints. The professional must take special care not to generate major complications in the patient’s body and limbs, which will be very weak after the heart attack.

For his part, the specialist doctor (the neurologist, in this case) will follow up on possible neurological complications and may request any type of test required (a CT scan, MRI, etc.).

Neuropsychological rehabilitation

The role of the neuropsychologist in these cases is to rehabilitate the higher cognitive functions that have been affected . In lacunar infarctions, for example, the executive functions, which are responsible for planning, reviewing and evaluating complex information that helps the individual adapt to the environment and achieve goals effectively, may be affected.

The neuropsychologist, through the application of individualized programs and the performance of specific tasks, will help the patient to restore and/or compensate the cognitive deficits caused by the injury, so that the person recovers his autonomy and can become functional again in all areas of his life (family, work and social).

Occupational and psychological therapy

The main objective of occupational therapy is to enable the patient to participate in the activities of daily living . The job of the occupational therapist is to facilitate that the individual, after the recovery period, is able to modify his or her environment so that he or she can once again participate in social and community activities.

Psychological therapy will help the patient to improve the skills that have been impaired and to recover from the emotional damage that such a disorder causes to the patient and his or her immediate environment. The psychologist must provide the patient with the necessary tools to achieve the psychological well-being and vital balance that every person needs after a process such as this.

Bibliographic references:

  • Arboix, A., García-Plata, C., García-Eroles, L., Massons, J., Comes, E., Oliveres, M., & Targa, C. (2005). Estudio clínico de 99 pacientes con apoplejía sensorial pura. Journal of neurology, 252(2), 156 – 162.
  • Fisher CM (1965) Golpe sensorial puro que involucra la cara, el brazo y la pierna. Neurología 65:76 – 80.
  • Grau-Olivares, M., Arboix, A., Bartrés-Faz, D., & Junqué, C. (2004). Alteraciones neuropsicológicas en los infartos cerebrales de tipo lacunar. Mapfre Medicina, 15(4), 244 – 250.