Agnosias and Apraxias PDF

AGNOSIAS ⚫ Agnosia refers to a neurological disorder characterized by the inability to recognize or interpret sensory information (e.g., objects, sounds, or smells), despite having intact sensory organs and basic perception. ⚫ Agnosia is the loss of the ability to recognize objects, face...

AGNOSIAS ⚫ Agnosia refers to a neurological disorder characterized by the inability to recognize or interpret sensory information (e.g., objects, sounds, or smells), despite having intact sensory organs and basic perception. ⚫ Agnosia is the loss of the ability to recognize objects, faces, voices, or places. It’s a rare disorder involving one (or more) of the senses. ⚫ It results from brain damage—typically in areas responsible for sensory processing, such as the occipital or temporal lobes. Types of Agnosias ⚫ Agnosias are classified based on the sensory modality affected. Below are the major types: ⚫ 1.Visual Agnosia ⚫ Inability to recognize objects, faces, or written words through vision, despite normal eyesight. ⚫ Subtypes: ◦ Apperceptive Agnosia: Inability to perceive the whole form of an object (issues with visual perception). ◦ Example: A patient can see shapes and colors but cannot recognize or copy a simple drawing of an apple. ◦ Associative Agnosia: Can perceive objects but unable to recognize or assign meaning to them (e.g., sees a key but doesn't know what it is). ◦ Example: A person can describe the appearance of a watch (round, silver) but doesn’t know it is used to tell time. ◦ Prosopagnosia: Inability to recognize familiar faces (also called "face blindness"). Example: A patient cannot recognize their spouse’s face but can identify them by voice or clothing. ◦ Alexia: Difficulty recognizing written words (word blindness). Example: A person cannot read a newspaper but can write notes, suggesting intact language production. ⚫ 2. Auditory Agnosia ⚫ Inability to recognize sounds despite normal hearing. ⚫ Subtypes: ◦ Verbal Auditory Agnosia (Pure Word Deafness): Difficulty understanding spoken language. A person hears spoken words as meaningless sounds, like a foreign language, even though they can read the same words and understand. ◦ Non-Verbal Auditory Agnosia: Inability to recognize non-verbal sounds (e.g., a phone ringing or dog barking). A patient hears a phone ring but cannot recognize the sound, even though they can still answer the phone ◦ Amusia: Inability to recognize musical tunes or rhythms. A person no longer recognizes a familiar tune (e.g., "Happy Birthday") but can still understand spoken words. ⚫ 3.Tactile Agnosia (Astereognosis) ⚫ Inability to recognize objects by touch alone, despite normal tactile sensation (e.g., unable to identify a pen with eyes closed). patient is unable to identify a coin in their hand by touch alone but can visually recognize it as a coin when shown. ⚫ 4. Olfactory Agnosia ⚫ Inability to identify or recognize familiar smells, even though the sense of smell is intact. A person cannot identify the smell of coffee, even though they can distinguish that it smells “strong.” ⚫ 5. Gustatory Agnosia ⚫ Inability to recognize or distinguish between different tastes, despite intact taste perception. A person tastes something salty but cannot differentiate between salt and sugar. ⚫ 6. Somatosensory Agnosia ⚫ Inability to recognize parts of one’s body or differentiate sensory stimuli on the skin. ⚫ Example: Asomatognosia (failure to recognize a part of one’s body, such as a limb). A patient denies ownership of their left hand and believes it belongs to someone else, despite it being attached to their body. Apraxia ⚫ Apraxia is a neurological condition that makes it difficult or impossible to make certain movements. This happens even though your muscles are normal and you have the understanding and desire to make these movements. ⚫ Apraxia is inability to carry out learned purposeful movement despite the presence of a good motor, sensory, or coordination function. Both the desire and the capacity to move are present but the person simply cannot execute the act. ⚫ It is not due to muscle weakness or paralysis but rather a disruption in the brain's ability to plan, sequence, and execute movements. Apraxia is often associated with damage to the parietal lobe, frontal lobe, or connections between these regions, and it can result from stroke, brain injury, or neurodegenerative diseases. Dyspraxia ⚫ Milder forms of apraxia are known as dyspraxia. This condition starts in childhood and causes problems with movement and coordination. It can affect both your fine and gross motor skills, as well as your balance and motor planning. This may make it hard to do things like riding a bike, writing, or tying your shoe. Dyspraxia isn’t as severe as apraxia because you only lose part of your motor ability. With apraxia, you totally lose your ability to make certain movements.You might also hear dyspraxia called developmental coordination disorder (DCD). Signs and symptoms ⚫ Inability to perform movement in the absence of any physical paralysis ⚫ Commands to move are understood, but cannot be executed. ⚫ Movement is very clumsy, uncontrolled and inappropriate. ⚫ Involuntary an unintentional movement is very common. ⚫ Apraxia is sometimes accompanied by a person’s loss of ability to comprehend or use words (Aphasia) Types of apraxia ⚫ 1. Limb Apraxia ⚫ This type affects the ability to perform coordinated movements with the arms and legs, even though the muscles are functioning normally. ⚫ Ideomotor Apraxia: The person can conceptualize the task but struggles to execute it, especially on command. They have difficulty executing learned motor tasks on command, even though they can perform the task. ⚫ Example: The patient cannot wave goodbye when asked, but may wave naturally later. ⚫ Ideational Apraxia: The person has difficulty understanding the sequence of steps involved in a complex task (e.g., using a toothbrush and toothpaste in the correct order). Eg. When presented in the clinic with a toothbrush and toothpaste and told to brush the teeth, the patient may put the tube of toothpaste in the mouth, or try to put toothpaste on the toothbrush without removing the cap. 2. Apraxia of Speech (Verbal Apraxia) ⚫ This form specifically affects the motor planning required for speech production. The individual knows what they want to say but struggles to move their lips, tongue, and vocal apparatus correctly to form words. It is common in children with Childhood Apraxia of Speech (CAS) and can also occur in adults after a stroke or brain injury. ⚫ Example: ⚫ A person knows they want to say “cat” but repeatedly produces incorrect sounds like "tat" or "gat." ⚫ A child with Childhood Apraxia of Speech (CAS) struggles to say “ball,” even though they understand the word and what it represents. They may try several times, with inconsistent errors each time. 3. Buccofacial or Orofacial Apraxia ⚫ This type affects the ability to perform non-speech movements involving the mouth and face, such as blowing, licking lips, or whistling, despite having intact muscle function. ⚫ Example: ⚫ When asked to blow a kiss, the person cannot coordinate their lips to perform the gesture. ⚫ A person is unable to whistle or puff their cheeks, despite understanding the task. ⚫ 4. Constructional Apraxia ⚫ This refers to difficulties in performing tasks that require spatial organization, such as assembling objects or drawing shapes. It is often associated with damage to the parietal lobe and is common in conditions like stroke or Alzheimer’s disease. ⚫ Example: ⚫ A child is given a model made of building blocks and asked to replicate it but cannot assemble the pieces correctly. ⚫ An adult is asked to draw a clock but places the numbers in random positions or forgets to include some of them. ⚫ 5. Dressing Apraxia ⚫ This type involves difficulty in putting on clothes correctly, such as getting dressed in the wrong order or misaligning garments. It is also linked to damage in brain regions responsible for spatial awareness. ⚫ Example: ⚫ A person tries to wear a sweater but ends up putting it on backward or inserting their arms into the wrong holes. ⚫ They might layer clothes incorrectly, like putting on a coat before wearing a shirt. ⚫ 6. Gait Apraxia ⚫ This involves difficulty in initiating and coordinating walking movements, even though the legs are physically capable. It is commonly seen in older adults and in conditions like Parkinson’s disease or after a stroke. ⚫ Example: ⚫ A person appears stuck when trying to start walking and shuffles forward with hesitation, even though their legs function normally. ⚫ They have difficulty adjusting their pace when crossing a road, stopping, or turning. ⚫ 7. Oculomotor Apraxia ⚫ This type affects the voluntary movement of the eyes. Individuals may struggle to move their eyes on command or shift their gaze between objects. ⚫ Example: ⚫ A person struggles to shift their gaze from one object to another when asked to look at different points in a room. ⚫ When reading, they have difficulty moving their eyes smoothly across the text and often lose their place. Understanding Aphasias ⚫ Aphasia is a language disorder caused by brain damage, affecting the production or comprehension of speech and the ability to read or write. ⚫ Aphasia is a language disorder caused by damage to specific areas of the brain that control language. It affects the ability to speak, understand speech, and use written language. ⚫ Aphasia is most commonly caused by stroke but can also result from traumatic brain injury, brain tumors, or progressive neurological conditions. Neurological Basis of Language ⚫ Broca’s Area: Located in the left frontal lobe, associated with speech production. ⚫ Wernicke’s Area: Located in the left temporal lobe, associated with language comprehension. ⚫ Arcuate Fasciculus: A bundle of nerve fibers connecting Broca’s and Wernicke’s areas, essential for coordinating speech and comprehension. ⚫ Other Areas: Angular gyrus, supramarginal gyrus, and the role of the right hemisphere. Types of Aphasias ⚫ 1. Broca’s Aphasia (Expressive Aphasia): ⚫ Location: Damage to Broca’s area in the frontal lobe. ⚫ Broca's aphasia or expressive aphasia is when people find it very difficult to find and say the right words, although they probably know exactly what they want to say. ⚫ People with Broca's aphasia may only be able to say single words or very short sentences, although it's usually possible for other people to understand what they mean. This can be very frustrating. ⚫ The features of Broca's aphasia are: ⚫ Severely reduced speech, often limited to short utterances of less than four words. ⚫ Limited vocabulary. ⚫ Clumsy formation of sounds. ⚫ Difficulty writing (but the ability to read and understand speech). ⚫ Example: "Want… coffee… now." (Speech is telegraphic, with many pauses.) 2. Wernicke's aphasia ⚫ Wernicke's aphasia or receptive aphasia is when someone is able to speak well and use long sentences, but what they say may not make sense. They may not know that what they're saying is wrong, so may get frustrated when people don't understand them. ⚫ Location: Damage to Wernicke’s area in the temporal lobe. ⚫ Symptoms: Fluent but nonsensical speech; difficulty understanding spoken or written language. ⚫ The features of Wernicke's aphasia are: ⚫ Impaired reading and writing. ⚫ An inability to grasp the meaning of spoken words (producing connected speech is not affected). ⚫ An inability to produce sentences that hang together. ⚫ The intrusion of irrelevant words in severe cases. ⚫ Example: "The sky is musical today." (Speech sounds fluent but lacks meaning.) ⚫ 3. Global Aphasia: ⚫ Global aphasia is the most severe form of aphasia, involving extensive damage to both language production and comprehension areas. It affects all aspects of communication, including speaking, understanding, reading, and writing. ⚫ Causes: ⚫ Large stroke affecting both Broca’s area (speech production) and Wernicke’s area (comprehension). ⚫ Severe traumatic brain injury or tumor impacting multiple regions in the left hemisphere. ⚫ Symptoms: ⚫ Speaking: Extremely limited speech, often restricted to a few words or sounds (like "yes," "no," or repeated syllables). ⚫ Comprehension: Difficulty understanding both spoken and written language. ⚫ Writing and Reading: Severely impaired reading and writing abilities. ⚫ Example: ⚫ When asked, “What’s your name?” the patient might respond with “Ba-ba” or be unable to answer at all. ⚫ They may also struggle to follow simple commands, such as "Raise your hand" or "Point to the door." 4. Anomic Aphasia: ⚫ Anomic aphasia is characterized by word-finding difficulties, particularly with nouns and verbs. The person knows what they want to say but struggles to retrieve specific words. It is often the mildest form of aphasia and can occur after recovery from other types. ⚫ Symptoms: ⚫ Speaking: Fluent speech, but frequent pauses as the person searches for words. ⚫ Comprehension: Generally unaffected; the person can understand speech and follow instructions. ⚫ Circumlocution: Using vague phrases or descriptions instead of the missing word. ◦ Example: Instead of saying “pen,” they may say, “the thing you use to write.” ⚫ Reading and Writing: Often intact, but they may also struggle with word retrieval in writing. ⚫ Example: ⚫ Conversation: ◦ Therapist: “What’s this?” (pointing to a picture of a cup) ◦ Patient: “Uh... it’s... you drink from it... oh, I know this... it’s a... mug?” 5. Primary progressive aphasia (PPA) ⚫ Primary Progressive Aphasia (PPA) is a neurodegenerative disorder that gradually impairs language abilities. Unlike other types of aphasia caused by acute brain damage, PPA is a progressive condition associated with frontotemporal dementia or Alzheimer’s disease ⚫ Primary progressive aphasia (PPA) is a condition where language capabilities become slowly and progressively worse, leading to a gradual loss of the ability to: ⚫ Read. ⚫ Write. ⚫ Speak. ⚫ Understand what other people are saying. ⚫ Deterioration can happen slowly, over a period of years. Other mental functions such as memory, reasoning, insight and judgement are not usually affected. 6. Conduction Aphasia ⚫ Conduction aphasia results from damage to the arcuate fasciculus, a bundle of nerve fibers connecting Broca’s and Wernicke’s areas. It mainly affects repetition ability, though comprehension and speech remain relatively intact. ⚫ Causes: ⚫ Stroke affecting the parietal or temporal lobe. ⚫ Brain injury damaging the connections between language areas. ⚫ Symptoms: ⚫ Speaking: Fluent but with frequent errors (phonemic paraphasias), where patients substitute or mispronounce words. ⚫ Repetition: Patients cannot accurately repeat phrases or sentences, especially longer ones. ⚫ Comprehension: Largely preserved; patients understand most of what they hear and read. ⚫ Awareness: Patients are often aware of their errors and attempt to correct them, leading to frustration. ⚫ Example: ⚫ Therapist: “Say the word ‘telephone.’” ⚫ Patient: “Tefele... no, wait, telelephone… I mean, telephone.” Difference between Agnosia, Aphasia, and Apraxia