Unlocking Language: How different regions of the brain process language and what happens when it fails
Introduction
Language processing involves our ability to communicate, think, and share ideas. However, for individuals with dyslexia, language can be more challenging. Dyslexia, a condition affecting reading, spelling, and language comprehension, is now better understood through recent brain research. This research sheds light on how the brain processes language, it’s impact on a person’s reading abilities and how multisensory language instruction can aid in addressing language processing difficulties often associated with dyslexia. This first blog post provides an overview explanation of how the brain lobes process language and describes the specific language difficulties caused when each lobe is not working at optimum performance. The second blog post dives into how Orton Gillingham helps the brain process language more efficiently using research-based strategies.
The Role of the Brain in Language Processing
Language processing occurs within different regions of the brain. These include the frontal lobe, temporal lobe, parietal lobe, and occipital lobe. These brain areas work together to help us understand and use language effectively. Dyslexia often involves differences in these areas, making language processing more difficult.
Frontal Lobe
What is it’s function?
This lobe, located at the front of the brain, plays an important role in executive functions like decision-making, problem-solving, and planning. It’s also responsible for motor control and aspects of speech production. For example, when you decide to say a specific word, the frontal lobe is responsible for organizing the motor movements necessary to articulate that word, like coordinating the movement of your tongue, lips, and vocal cords to produce the sounds correctly.
What is the impact of reduced function?
Reduced frontal lobe function can impact a person’s ability to plan and organize thoughts, making the precise movements for speech difficult. They may have difficulty saying words correctly because of difficulties in coordinating their tongue, lips, and vocal cord movements, making it challenging to communicate clearly.
Temporal Lobe
What is it’s fuction?
These lobes, situated on either side of the brain, are important for language processing, memory, and auditory perception. It helps us understand language by working like a mental dictionary. When you hear or read a word, your temporal lobe stores its meaning, so when you encounter that word again, it retrieves its definition, allowing you to comprehend and use it in a sentence.
What is the impact of reduced function?
The temporal lobe’s role as a “mental dictionary” might not work as smoothly. When they hear or read a word, their temporal lobe may struggle to store and retrieve its meaning efficiently. This can result in difficulties comprehending the words and sentences they encounter, making reading and language understanding more challenging for individuals with dyslexia.
Parietal Lobe
What is it’s function?
This lobe, positioned near the top and back of the brain, contributes to language processing by helping us understand the spatial aspects of language. For example, when someone describes the location of an object or the spatial relationship between two items using words like “above,” “below,” or “next to,” the parietal lobe assists in visualizing and comprehending these spatial details. It provides the ability to link spoken and written language to memory and understand what is heard and read. Additionally, it plays a role in processing sensory information related to language, such as touch or sensations, which can enhance our overall understanding of linguistic content. The angular gyrus, located in the left parietal lobe, is essential for reading and phonological processing, particulary converting written words into spoken language.
What is the impact of reduced function?
Difficulties in the parietal lobe can make it hard for a person to comprehend descriptions that involve spatial relationships or sensory experiences in text. For example, they may struggle to visualize directions or the positions of objects described in a story, which can make it challenging to fully understand what they are reading.
Occipital Lobe
What is it’s function?
This lobe, located at the back of the brain, primarily processes visual information by recognizing written words and converting them into meaningful information. When you read, the occipital lobe plays a critical role in identifying letters and words, allowing you to understand the written language. It works closely with other brain regions, such as the temporal and parietal lobes, to integrate visual information with language comprehension, enabling you to make sense of written text.
What is the impact of reduced function?
This can impact individuals by making it harder to recognize and process written words. This difficulty can lead to struggles in reading, as they might have trouble accurately identifying letters and words, impacting their overall understanding of the text. This can make reading a slower and more effortful task for people with dyslexia.
Precentral Gyrus
What is it’s function?
The precentral gyrus (the “motor strip“), a part of the frontal lobe in the brain, plays a vital role in enabling us to communicate through speech. It achieves this by overseeing and controlling the muscle movements necessary for producing speech sounds. For instance, when we say words like “motorcycle,” the precentral gyrus ensures that the muscles controlling our lips, tongue, and vocal cords work together with precise coordination to articulate each sound or phoneme, such as “mo-to-rcy-cle.” It’s essentially the conductor orchestrating the symphony of muscle movements required for clear and fluent speech.
Moreover, damage or dysfunction in the precentral gyrus can lead to speech disorders like apraxia, where individuals struggle with planning and executing these motor movements effectively. This can result in difficulty pronouncing words correctly, impacting their ability to express themselves coherently. In essence, the precentral gyrus serves as a crucial component in the complex machinery of language processing, particularly in the motor aspects of speech production.
What is the impact of reduced function?
When the precentral gyrus is not functioning as it should, individuals may struggle with connecting letters to their corresponding sounds and coordinating the precise muscle movements needed for speech. For example, when encountering the word “motorcycle,” they might find it challenging to associate letters with correct sounds and struggle with pronouncing the word accurately. This difficulty in linking written symbols to the motor processes required for speech can lead to reading inaccuracies and pronunciation challenges, making it harder for them to read and speak fluently.
Postcentral Gyrus
What is it’s function?
The postcentral gyrus (the “sensory strip“), located in the parietal lobe, handles touch and body sensations, not language directly. However, it helps with language by receiving feedback from the mouth and throat, important for speaking. This feedback, along with input from other language-related areas in the brain, helps coordinate speech movements and overall language understanding. While the postcentral gyrus isn’t the main language processor, it plays a supporting role in the complex process of communication.
What is the impact of reduced function?
The postcentral gyrus in the brain is like a control center for feeling touch and movement. Even though it’s not directly responsible for speaking, if it gets damaged, it can disrupt those muscles work together. This disruption can cause problems with the small, precise movements needed for clear speech. The postcentral gyrus communicates with other parts of the brain in charge of muscle actions, and if there’s an issue, it can interfere with the teamwork needed for speech. So, if the postcentral gyrus is damaged, it can make it difficult for someone to speak clearly and get their words just right.
Broca’s Area and Wernicke’s Area
What are their function?
Broca’s area, located in the left frontal lobe, is primarily responsible for language production. It helps plan and execute the physical aspects of speech, such as forming words and sentences. This is where expressive language is primarily controlled. Wernicke’s area, primarily located in the left temporal lobe, is essential for language comprehension. It interprets and understands the meaning of words and sentences. This is where receptive language is primarily controlled. Both areas work together in fluent communication, with Broca’s area handling speech production and Wernicke’s area managing language comprehension.
What is the impact of reduced function?
Damage to Broca’s area, responsible for speech production and fluency, can lead to a disconnection between a person’s thoughts and their ability to use words. Consequently, affected patients frequently experience the sensation of comprehending what they want to say but unable to find the right words to express these thoughts.
Damage to Wernicke’s area, essential for language comprehension, makes it difficult to understand language and form meaningful sentences.
Angular Gyrus
What is it’s function?
The angular gyrus, located in the in the parietal lobe where the temporal and occipital lobe connect, is primarily responsible for reading, linking written words to their corresponding sounds and meanings, as well as in processing words semantics. This area makes it possible to associate a printed word with sensory experiences (Ex: hearing how the word sounds when said aloud, recognizing the kinesthetic movement used to write the word, feeling the tactile senses within the mouth as it moves to speak the word). It acts as an area of communication between the parietal lobe, the temporal lobe, and the occipital lobe.
What is the impact of reduced function?
This can lead to challenges in converting written words into their corresponding sounds and meanings, which are critical for reading comprehension. Individuals may struggle with word recognition, have difficulty associating letters with the correct sounds, and face spelling and writing challenges, as the angular gyrus plays a role in these processes. Furthermore, difficulties in language integration can affect their overall reading and language comprehension abilities, making it harder for them to read fluently and understand written texts.
The brain is composed of both a left and a right hemisphere, each of which are responsible for performing certain functions. The left hemisphere contains the primary components used during the reading process and is, in cases of strong readers, often observed to be slightly larger than the right hemisphere.
Left Hemisphere
- Reading
- Listening
- Writing
- Speech
- Comprehension
- Logical
- Sequential
- Analytical
Right Hemisphere
- holistic
- creativity
- interpretation of 3-dimensional forms
- artistic ability
- musical ability
- creative ability
- inductive in reasoning
- spatial ability- drawing pictures, solving puzzles
- nonverbal language
- intuition
How Dyslexia Alters Language Processing
While the exact causes of dyslexia are not yet fully understood, research suggests that it may involve differences in brain structure and function.
Multiple brain imaging studies provide evidence that the brain structure of persons with dyslexia show less gray matter (consisting of nerve cells used for processing information) and white matter (helps different areas of the brain communicate with each other) in the language areas of the brain. These imaging studies have also found that the right side of a dyslexic brain tends to be the same size as the left side, indicating the possibility that these people are compensating by using the right side of the brain during the reading process.
Evidence of differences in brain function has been gathered from studies conducted on dyslexic and non-dyslexic individuals while they were performing reading-related tasks where brain imaging showed an underactivation in the area involved in critical reading skills and an overaction in the areas of the brain where compensating strategies were potentiall being used in order to accomplish these reading tasks.
So, what attention and language processing areas are affected in a dyslexic brain?
1. Phonological Processing Deficits:
One of the hallmark characteristics of dyslexia is difficulty in phonological processing. This involves recognizing and manipulating the sounds of spoken language. Individuals with dyslexia may struggle with phonemic awareness, which is the ability to identify and manipulate individual sounds in words.
2. Difficulty with Decoding and Word Recognition:
Dyslexic individuals often have difficulty decoding words, which means they may struggle to break down words into their individual sounds and recognize the corresponding letters. This difficulty can lead to problems with word recognition, making reading a slow and effortful process.
3. Working Memory Challenges:
Dyslexia is associated with challenges in working memory, which is crucial for holding and manipulating information while engaged in cognitive tasks. Weak working memory can impact reading comprehension and the ability to integrate information across sentences and paragraphs.
4. Visual Processing Issues:
While dyslexia is primarily a phonological processing issue, some individuals may also experience challenges in visual processing. This can affect the recognition of visual symbols, making it difficult to distinguish between letters that are similar in appearance.
5. Difficulty with Rapid Naming:
Rapid naming refers to the ability to quickly and accurately name a series of familiar items, such as letters or numbers. Individuals with dyslexia may struggle with rapid naming, which can further impact their reading fluency.
6. Orthographic Processing Challenges:
Orthography refers to the conventional spelling system of a language. Dyslexic individuals may have difficulties with orthographic processing, which involves recognizing and recalling the correct spellings of words.
7. Neurological Differences:
- Brain imaging studies have identified differences in the brain structure and function of individuals with dyslexia. Areas involved in language processing, such as the left hemisphere’s reading-related regions, may show atypical activation patterns or structural differences.
long passages of text.
The Role of Multisensory Orton Gillingham Instruction
The Orton-Gillingham Approach: A Multisensory Journey
Now that we’ve touched on the neural landscape of language processing, let’s explore how the Orton-Gillingham approach leverages the brain’s sensory capacities to nurture language skills, particularly in individuals with dyslexia.
- Visual Learning: Engaging the Occipital Lobe
The occipital lobe, primarily responsible for processing visual information, is engaged in the Orton-Gillingham approach to aid in reading instruction.
- Visual Aids: Dyslexic individuals often struggle with recognizing and recalling visual symbols, such as letters and words. Orton-Gillingham utilizes visual aids like flashcards, letter tiles, and color-coding to enhance visual memory and recognition. These tools capitalize on the brain’s natural visual processing abilities.
Auditory Learning: Tapping into Temporal and Parietal Lobes
While the temporal lobe is the central hub for language processing, the parietal lobe also plays a role in auditory processing. The Orton-Gillingham approach incorporates auditory learning strategies to support reading and language skills.
- Phonics Instruction: Dyslexic learners benefit from explicit phonics instruction that helps them understand the connection between sounds and letters. For example, students write words containing recently introduced phonograms saying each letter out loud while writing it. This process activates the auditory processing centers in the temporal and parietal lobes, allowing individuals to better grasp the nuances of language and solidify the letter-sound connection.
Kinesthetic-Tactile Learning: Activating the Sensory-Motor Cortex
The sensory-motor cortex, located in the parietal lobe, is engaged in kinesthetic-tactile learning. Dyslexic individuals often struggle with the physical aspect of writing and reading. The Orton-Gillingham approach incorporates activities that leverage these sensory-motor areas.
- Tactile Engagement: Dyslexic students may engage in activities like tracing letters in sand, shaping them with clay, or tapping out rhythms. These activities stimulate the sensory-motor cortex, allowing individuals to feel and manipulate letters and words, enhancing their kinesthetic-tactile learning experience.
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