Left hemisphere brain damage can lead to difficulties with language and reasoning skills, among other secondary effects. Understanding the potential effects of left hemisphere brain damage can help you quickly identify complications and seek early management interventions for them.
To help you understand what to expect following a traumatic brain injury to the left hemisphere, this article will discuss:
Left Hemisphere Functions
To understand what to expect following left hemisphere brain damage, it helps to understand how the brain works. The brain acts as the control center for the entire body and is responsible for both physical and cognitive functions. It consists of two hemispheres (left and right), each of which governs movement on the opposite side of the body. For example, the left hemisphere commands movement on the right side of the body, and vice versa.
For most individuals, the right side of the brain is responsible for non-verbal, intuitive, and creative actions such as musical and artistic abilities. On the other hand, the left hemisphere is primarily in charge of regulating verbal, analytical, and logical functions.
Some functions controlled by the left hemisphere include:
- Logic and reasoning
- Number skills
- Analytic thought
- Language comprehension
- Right-hand control
- Sequential thinking
The left side of the brain is also considered the “language hub” of the brain. It is where the bulk of your language abilities lie, particularly your ability to produce and understand language.
Now that you’re familiar with what functions are regulated by the left hemisphere, let’s discuss the potential effects of left hemisphere brain damage.
Left Hemisphere Brain Injury Symptoms
Depending on the location of the injury, left hemisphere damage can cause a variety of secondary effects that impact your movement, communication, and cognitive skills.
Below are some common effects that may occur following left hemisphere brain damage:
Aphasia is a language disorder that affects a person’s ability to produce and understand speech. It may also cause difficulties with reading and writing.
Several types of aphasia may develop after damage to the left hemisphere. The three most common are:
- Global aphasia. This is the most severe form of aphasia. A person with global aphasia cannot speak, read, or write and may minimally understand others.
- Broca’s aphasia. Also known as “expressive” or “non-fluent” aphasia. With Broca’s aphasia, a person may understand what others say, but cannot produce their own words. As a result, they may struggle to find the right words to say and repeatedly use short sentences or single words to get their point across. Individuals with Broca’s aphasia are often able to read (silently, not out loud), but frequently have trouble with writing.
- Wernicke’s aphasia. This form of aphasia is the opposite of Broca’s aphasia. With Wernicke’s aphasia, a person can speak fluently, but cannot understand language. For example, they may be unable to read, recognize what others are saying, and speak in long, nonsensical sentences.
2. Apraxia of Speech
Not all language problems are caused by aphasia. Sometimes following left hemisphere brain damage, the brain loses its ability to communicate fluently with the facial muscles. This leads to a condition called apraxia of speech.
With apraxia of speech, the brain cannot plan and coordinate the sequences of oral motor movements necessary for speech articulation. This may make it difficult to form and pronounce words correctly, even though you may not have weakness in the muscles involved in speech and you know what words you want to say.
3. Dysarthria (slurred speech) and dysphagia (difficulty swallowing)
Two other speech disorders associated with left hemisphere brain damage are dysarthria and dysphagia.
Dysarthria refers to a weakness of the mouth and tongue, which causes a person to speak more slowly and/or slur their speech. Dysphagia, on the other hand, refers to difficulties swallowing, often due to weakness of the throat muscles used for swallowing.
The two disorders often appear together because speaking requires many of the same muscles used for swallowing.
4. Right-Side Weakness (hemiparesis)
Because the left side of the brain controls movement on the right side of the body, left hemisphere brain damage may cause right-side weakness (hemiparesis). In severe cases, a person can experience full paralysis on their right side (right sided hemiplegia).
These conditions occur because of damage to the primary motor cortex, which lies in the frontal lobe of the brain. If the left half of the motor cortex sustains damage, movement on the right side of the body will be affected.
After damage to the left motor cortex, a person may struggle to:
- Lift their right arm
- Move the fingers on their right hand
- Control the right side of their face
- Walk due to balance difficulties and weakness of the right leg
To restore movement, you should practice physical therapy exercises that utilize your affected muscles. This will stimulate the brain and promote adaptive changes in its circuitry.
5. Computation and Reasoning Problems
Lastly, left hemisphere brain damage may cause difficulties with math and logic skills. It may also affect abstract reasoning and organization skills. Individuals with left hemisphere damage often struggle to keep their thoughts straight, which may make problem-solving more difficult.
Some other cognitive skills that left hemisphere injuries can affect include:
- Ability to gather and sort information
- Strategy and planning
These skills are comprised of a group of abilities known as executive functions. To help you understand how to recover these functions, as well as others affected by left hemisphere brain damage, the following section will discuss treatment.
Left Hemisphere Brain Damage Treatment
While the effects of left hemisphere brain damage can be serious, they may not be permanent. The brain possesses a remarkable ability to make adaptive changes known as neuroplasticity. This ability allows the brain to rewire functions affected by damage to unaffected regions of the brain.
To activate neuroplasticity, you must engage in highly repetitive and intensive practice of affected movements or skills. This helps stimulate the brain and reinforce demand for those functions.
Some rehabilitative therapies that can help you promote neuroplasticity after left hemisphere brain damage include:
Speech therapy can help individuals overcome aphasia, apraxia, and dysarthria. Additionally, a speech therapist may teach individuals effective practices to develop their cognitive abilities, such as their executive functioning skills. Speech therapists help evaluate the severity of an individual’s orofacial and cognitive impairments and develop personalized rehabilitation plans to improve them.
For individuals with more severe forms of language impairments, a speech therapist may teach them how to use alternative forms of communication to improve their quality of life. Speech therapists can also address dysphagia through oral motor exercises and recommending foods with softer textures as needed.
To recover motor control on the right side of the body, individuals should participate in physical therapy after left hemisphere brain damage. A physical therapist will guide the individual through targeted exercises to stimulate weakened muscles, improve balance, and promote neuroplasticity in the brain.
Constraint-induced movement therapy
Constraint-induced movement therapy is a type of physical or occupational therapy that focuses on continuous use of the affected side. For individuals with hemiparesis on their right side, the left side of their body will be constrained to force use of the affected right side. The continuous use of the right side will help stimulate the brain and promote neuroplasticity. This is generally a rather intensive form of therapy, and typically focuses mostly on improving affected upper extremity functions.
Occupational therapy focuses on helping individuals maximize their functional independence. This often involves practicing activities of daily living and educating patients about disability rights, adaptive techniques, and potential risks associated with their condition.
Ultimately, recovery after left hemisphere brain damage focuses on highly repetitive, task-specific training that encourages the brain to make adaptive changes. Thousands of repetitions are required to promote neurological changes in the brain. Therefore, it’s essential for individuals to have hope, keep practicing, and trust in the process.
Left Hemisphere Brain Damage: Key Points
Left hemisphere brain damage can affect a variety of skills including communication, motor function, and executive functions. Often, these skills can be improved by engaging neuroplasticity in the brain. This can be accomplished by participating in rehabilitative therapies and practicing consistent repetitions of targeted exercises and activities.
We hope this article helped you understand the potential outcomes of left hemisphere brain damage and how to improve affected functions.