Lacunar Strokes Types and Symptoms

Lacunar strokes are strokes caused by the occlusion of a small branch of a larger blood vessel. Because of the way blood vessels divide in the brain, lacunar strokes tend to occur in areas located in the deeper parts of the brain, where many of the smaller blood vessel branches are located.

As most brain areas perform a limited set of brain functions, the symptoms of a given lacunar stroke usually correspond to the area where the damage occurred. The symptoms fall within one of the following five categories.

Doctor viewing a series of MRI (Magnetic Resonance Imaging) brain scans on a screen
Rafe Swan / Getty Images

Pure Motor Strokes

Pure motor strokes are the most common type of lacunar strokes, accounting for more than 50% of all cases. Doctors use the technical term "pure motor paresis" to describe pure motor strokes.

"Paresis" is muscle weakness. The word "hemiparesis" means a weakness of one full side of the body. If a person has only upper limb weakness, it would not be hemiparesis.

Pure motor strokes usually involve the following parts of the brain:

All of these areas contain fibers that connect the "brain cortex," the area of the nervous system where the orders to initiate voluntary movements (walking, tapping your foot) originate. These areas of the nervous system activate muscles all over the body to move.

In most cases, the result of strokes in these areas is analogous to the inability that a puppeteer would have to move a marionette's wooden arm if the string that connected it to its handle was cut. In this example, the puppeteer represents the brain cortex, while the strings represent the areas affected in a pure motor lacunar stroke.


Pure motor strokes cause partial or complete weakness in the face, arm, and leg on one side of the body. The weakness can be in any of these parts alone, or in combination with either of the other two.

Most commonly, pure motor strokes cause either a combination of arm and leg weakness, sparing the face, or a combination of arm, leg, and facial weakness. However, symptoms can also occur in any one of these parts alone.

By definition, in pure motor strokes, there is no loss of sensation anywhere in the body, and there are no visual or speech symptoms.

Pure Sensory Lacunar Strokes

As their name implies, pure sensory lacunar strokes are strokes in which the only symptoms are sensory abnormalities, such as numbness or unusual perception of pain, temperature, or pressure. The overwhelming majority of pure sensory lacunar strokes affect a brain area called the thalamus, an area that is heavily involved in processing the senses from all over the body.

Sensations affected by a pure sensory stroke include touch, pain, temperature, pressure, vision, hearing, and taste.


Most cases of pure sensory lacunar stroke produce an absent or abnormal sensation in the face, arm, leg, and thorax, but only on one side of the body. In many cases, however, different body parts such as the fingers, the foot, or the mouth on one side are affected in isolation. A common type of pure sensory lacunar stroke is called Dejerine Roussy, which is an example of central pain syndrome.

Sensorimotor Lacunar Stroke

This type of lacunar stroke syndrome results from the blockage of a vessel that supplies both the thalamus and the adjacent posterior internal capsule. Another name for them is mixed sensorimotor stroke.


Because both a sensory and a motor area of the brain are affected by this kind of stroke, its symptoms include both sensory loss (due to damage to thalamus) and hemiparesis or hemiplegia (due to damage to internal capsule). Both the sensory and the motor abnormalities are felt on the same side of the body.

Ataxic Hemiparesis

This type of stroke is most commonly caused by lack of blood flow to one of the following areas of the brain:

  • Internal capsule
  • Corona radiata
  • Pons


Lacunar strokes in certain parts of these areas, which can also cause pure motor lacunar symptoms, can cause wobbliness and weakness in the arm or leg on one side of the body. Typically, the wobbliness (ataxia) is a much more bothersome symptom than the weakness in the affected arm or leg. The face is not usually involved.

Dysarthria Clumsy-Hand Syndrome

By definition, dysarthria clumsy-hand syndrome is a combination of symptoms caused by a lacunar stroke affecting the anterior portion of the internal capsule. In true cases of this syndrome, people suffer from both dysarthria (trouble speaking) and a clumsy hand.


As the name implies, a prominent feature of this syndrome is a disorder of speech called dysarthria. For the most part, dysarthria can be defined as difficulty pronouncing or forming words due to inadequate movements of the muscles in the voice box, also known as the larynx, the tongue, and other muscles in the mouth.

Aside from dysarthria, people with this syndrome complain of the clumsiness of hand movements on one side of the body. Usually, the affected hand has normal strength, but people complain of difficulty with fine movements such as writing, tying a shoelace, or playing the piano.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Jose Vega MD, PhD
Jose Vega MD, PhD, is a board-certified neurologist and published researcher specializing in stroke.