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Focal Neurologic Signs
Focal neurologic signs also known as focal neurological deficits or focal CNS signs are impairments of nerve, spinal cord, or brain function that affects a specific region of the body, e.g. weakness in the left arm, the right leg, paresis, or plegia. Focal neurological deficits may be caused by a variety of medical conditions such as head trauma, tumors or stroke; or by various diseases such as meningitis or encephalitis or as a side effect of certain medications such as those used in anesthesia. Neurological soft signs, are a group of non-focal neurologic signs. Frontal lobe signs Frontal lobe signs usually involve the motor system and may include many special types of deficit, depending on which part of the frontal lobe is affected: * unsteady gait (unsteadiness in walking) * muscular rigidity, resistance to passive movements of the limbs ( hypertonia) * paralysis of a limb ( monoparesis) or a larger area on one side of the body (hemiparesis) * paralysis head and eye movements ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central Nervous System
The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all parts of the bodies of bilaterally symmetric and triploblastic animals—that is, all multicellular animals except sponges and diploblasts. It is a structure composed of nervous tissue positioned along the rostral (nose end) to caudal (tail end) axis of the body and may have an enlarged section at the rostral end which is a brain. Only arthropods, cephalopods and vertebrates have a true brain (precursor structures exist in onychophorans, gastropods and lancelets). The rest of this article exclusively discusses the vertebrate central nervous system, which is radically distinct from all other animals. Overview In vertebrates, the brain and spinal cord are both enclosed in the meninges. The meninges provide a barrier to chemicals di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jacksonian Seizure
Focal seizures (also called partial seizures and localized seizures) are seizures which affect initially only one hemisphere of the brain. The brain is divided into two hemispheres, each consisting of four lobes – the frontal, temporal, parietal and occipital lobes. A focal seizure is generated in and affects just one part of the brain – a whole hemisphere or part of a lobe. Symptoms will vary according to where the seizure occurs. When seizures occur in the frontal lobe the patient may experience a wave-like sensation in the head. When seizures occur in the temporal lobe, a feeling of déjà vu may be experienced. When seizures are localized to the parietal lobe, a numbness or tingling may occur. With seizures occurring in the occipital lobe, visual disturbances or hallucinations have been reported. , Epilep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cortical Deafness
Cortical deafness is a rare form of sensorineural hearing loss caused by damage to the primary auditory cortex. Cortical deafness is an auditory disorder where the patient is unable to hear sounds but has no apparent damage to the anatomy of the ear (see auditory system), which can be thought of as the combination of auditory verbal agnosia and auditory agnosia. Patients with cortical deafness cannot hear any sounds, that is, they are not aware of sounds including non-speech, voices, and speech sounds. Although patients appear and feel completely deaf, they can still exhibit some reflex responses such as turning their head towards a loud sound. Cause Cortical deafness is caused by bilateral cortical lesions in the primary auditory cortex located in the temporal lobes of the brain. The ascending auditory pathways are damaged, causing a loss of perception of sound. Inner ear functions, however, remains intact. Cortical deafness is most often caused by stroke, but can also result from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporal Lobe
The temporal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain. The temporal lobe is involved in processing sensory input into derived meanings for the appropriate retention of visual memory, language comprehension, and emotion association. ''Temporal'' refers to the head's temples. Structure The temporal lobe consists of structures that are vital for declarative or long-term memory. Declarative (denotative) or explicit memory is conscious memory divided into semantic memory (facts) and episodic memory (events). Medial temporal lobe structures that are critical for long-term memory include the hippocampus, along with the surrounding hippocampal region consisting of the perirhinal, parahippocampal, and entorhinal neocortical regions. The hippocampus is critical for memory formation, and the surrounding medial temporal co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agnosia
Agnosia is the inability to process sensory information. Often there is a loss of ability to recognize objects, persons, sounds, shapes, or smells while the specific sense is not defective nor is there any significant memory loss. It is usually associated with brain injury or neurological illness, particularly after damage to the occipitotemporal border, which is part of the ventral stream. Agnosia only affects a single modality, such as vision or hearing. More recently, a top-down interruption is considered to cause the disturbance of handling perceptual information. Types Visual agnosia Visual agnosia is a broad category that refers to a deficiency in the ability to recognize visual objects. Visual agnosia can be further subdivided into two different subtypes: apperceptive visual agnosia and associative visual agnosia. Individuals with apperceptive visual agnosia display the ability to see contours and outlines when shown an object, but they experience difficulty if ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dyscalculia
Dyscalculia () is a disability resulting in difficulty learning or comprehending arithmetic, such as difficulty in understanding numbers, learning how to manipulate numbers, performing mathematical calculations, and learning facts in mathematics. It is sometimes colloquially referred to "math dyslexia", though this analogy is misleading as they are distinct syndromes. Dyscalculia is associated with dysfunction in the region around the intraparietal sulcus and potentially also the frontal lobe. Dyscalculia does not reflect a general deficit in cognitive abilities or difficulties with time, measurement, and spatial reasoning. Estimates of the prevalence of dyscalculia range between 3 and 6% of the population. In 2015 it was established that 11% of children with dyscalculia also have ADHD. Dyscalculia has also been associated with Turner syndrome and people who have spina bifida. Mathematical disabilities can occur as the result of some types of brain injury, in which case the t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dysgraphia
Dysgraphia is a learning disability of written expression, which affects the ability to write, primarily handwriting, but also coherence. It is a specific learning disability (SLD) as well as a transcription disability, meaning that it is a writing disorder associated with impaired handwriting, orthographic coding and finger sequencing (the movement of muscles required to write). It often overlaps with other learning disabilities and neurodevelopmental disorders such as speech impairment, attention deficit hyperactivity disorder (ADHD) or developmental coordination disorder (DCD). In the ''Diagnostic and Statistical Manual of Mental Disorders'' (''DSM-IV''), dysgraphia is characterized as a learning disability in the category of written expression, when one's writing skills are below those expected given a person's age measured through intelligence and age-appropriate education. The DSM is unclear in whether writing refers only to the motor skills involved in writing, or if i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dyslexia
Dyslexia, also known until the 1960s as word blindness, is a disorder characterized by reading below the expected level for one's age. Different people are affected to different degrees. Problems may include difficulties in spelling words, reading quickly, writing words, "sounding out" words in the head, pronouncing words when reading aloud and understanding what one reads. Often these difficulties are first noticed at school. The difficulties are involuntary, and people with this disorder have a normal desire to learn. People with dyslexia have higher rates of attention deficit hyperactivity disorder (ADHD), developmental language disorders, and difficulties with numbers. Dyslexia is believed to be caused by the interaction of genetic and environmental factors. Some cases run in families. Dyslexia that develops due to a traumatic brain injury, stroke, or dementia is sometimes called "acquired dyslexia" or alexia. The underlying mechanisms of dyslexia result from diffe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemispatial Neglect
Hemispatial neglect is a neuropsychological condition in which, after damage to one hemisphere of the brain (e.g. after a stroke), a deficit in attention and awareness towards the side of space opposite brain damage (contralesional space) is observed. It is defined by the inability of a person to process and perceive stimuli towards the contralesional side of the body or environment. Hemispatial neglect is very commonly contralateral to the damaged hemisphere, but instances of ipsilesional neglect (on the same side as the lesion) have been reported. Presentation Hemispatial neglect results most commonly from strokes and brain unilateral injury to the right cerebral hemisphere, with rates in the critical stage of up to 80% causing visual neglect of the left-hand side of space. Neglect is often produced by massive strokes in the middle cerebral artery region and is variegated, so that most sufferers do not exhibit all of the syndrome's traits. Right-sided spatial neglect is rare bec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proprioception
Proprioception ( ), also referred to as kinaesthesia (or kinesthesia), is the sense of self-movement, force, and body position. It is sometimes described as the "sixth sense". Proprioception is mediated by proprioceptors, mechanosensory neurons located within muscles, tendons, and joints. Most animals possess multiple subtypes of proprioceptors, which detect distinct kinematic parameters, such as joint position, movement, and load. Although all mobile animals possess proprioceptors, the structure of the sensory organs can vary across species. Proprioceptive signals are transmitted to the central nervous system, where they are integrated with information from other sensory systems, such as the visual system and the vestibular system, to create an overall representation of body position, movement, and acceleration. In many animals, sensory feedback from proprioceptors is essential for stabilizing body posture and coordinating body movement. System overview In vertebrates, limb v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parietal Lobe
The parietal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The parietal lobe is positioned above the temporal lobe and behind the frontal lobe and central sulcus. The parietal lobe integrates sensory information among various modalities, including spatial sense and navigation (proprioception), the main sensory receptive area for the sense of touch in the somatosensory cortex which is just posterior to the central sulcus in the postcentral gyrus, and the dorsal stream of the visual system. The major sensory inputs from the skin ( touch, temperature, and pain receptors), relay through the thalamus to the parietal lobe. Several areas of the parietal lobe are important in language processing. The somatosensory cortex can be illustrated as a distorted figure – the cortical homunculus (Latin: "little man") in which the body parts are rendered according to how much of the somatosensory cortex is devoted to them. The superior parietal lobule a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snout Reflex
The Snout reflex (also orbicularis oris reflex) or a "Pout" is a pouting or pursing of the lips that is elicited by light tapping of the closed lips near the midline. The contraction of the muscles causes the mouth to resemble a snout. This reflex is tested in a neurological exam and if present, is a sign of brain damage or dysfunction. Along with the "suck", palmomental reflexes and other reflexes, snout is considered a frontal release sign. These reflexes are normally inhibited by frontal lobe activity in the brain, but can be "released" from inhibition if the frontal lobes are damaged. They are normally present in infancy, however, and until about one year of age, leading to the hypothesis that they are primitive or archaic reflexes. Frontal release signs are seen in disorders that affect the frontal lobes, such as dementias, metabolic encephalopathies, closed head injuries, and hydrocephalus Hydrocephalus is a condition in which an accumulation of cerebrospinal fluid ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
