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Cognitive neuropsychology is a branch of cognitive psychology that aims to understand how the structure and function of the brain relates to specific psychological processes. Cognitive psychology is the science that looks at how mental processes are responsible for the cognitive abilities to store and produce new memories, produce language, recognize people and objects, as well as our ability to reason and problem solve. Cognitive neuropsychology places a particular emphasis on studying the cognitive effects of brain injury or neurological illness with a view to inferring models of normal cognitive functioning. Evidence is based on case studies of individual brain damaged patients who show deficits in brain areas and from patients who exhibit double dissociations. Double dissociations involve two patients and two tasks. One patient is impaired at one task but normal on the other, while the other patient is normal on the first task and impaired on the other. For example, patient A would be poor at reading printed words while still being normal at understanding spoken words, while the patient B would be normal at understanding written words and be poor at understanding spoken words. Scientists can interpret this information to explain how there is a single cognitive module for word comprehension. From studies like these, researchers infer that different areas of the brain are highly specialised. Cognitive neuropsychology can be distinguished from cognitive neuroscience, which is also interested in brain-damaged patients, but is particularly focused on uncovering the neural mechanisms underlying cognitive processes.
Henry Gustav Molaison, known widely as H.M., was an American who had a bilateral medial temporal lobectomy to surgically resect the anterior two thirds of his hippocampi, parahippocampal cortices, entorhinal cortices, piriform cortices, and amygdalae in an attempt to cure his epilepsy. Although the surgery was partially successful in controlling his epilepsy, a severe side effect was that he became unable to form new memories.
Split-brain or callosal syndrome is a type of disconnection syndrome when the corpus callosum connecting the two hemispheres of the brain is severed to some degree. It is an association of symptoms produced by disruption of, or interference with, the connection between the hemispheres of the brain. The surgical operation to produce this condition involves transection of the corpus callosum, and is usually a last resort to treat refractory epilepsy. Initially, partial callosotomies are performed; if this operation does not succeed, a complete callosotomy is performed to mitigate the risk of accidental physical injury by reducing the severity and violence of epileptic seizures. Before using callosotomies, epilepsy is instead treated through pharmaceutical means. After surgery, neuropsychological assessments are often performed.
Brenda Milner is a British-Canadian neuropsychologist who has contributed extensively to the research literature on various topics in the field of clinical neuropsychology. Milner is a professor in the Department of Neurology and Neurosurgery at McGill University and a professor of Psychology at the Montreal Neurological Institute. As of 2020, she holds more than 25 honorary degrees and she continued to work in her nineties. Her current work covers many aspects of neuropsychology including her lifelong interest in the involvement of the temporal lobes in episodic memory. She is sometimes referred to as the founder of neuropsychology and has been essential in its development. She received the Balzan Prize for Cognitive Neuroscience in 2009, and the Kavli Prize in Neuroscience, together with John O'Keefe, and Marcus E. Raichle, in 2014. She turned 100 in July 2018 and at the time was still overseeing the work of researchers.
Cerebral angiography is a form of angiography which provides images of blood vessels in and around the brain, thereby allowing detection of abnormalities such as arteriovenous malformations and aneurysms. It was pioneered in 1927 by the Portuguese neurologist Egas Moniz at the University of Lisbon, who also helped develop thorotrast for use in the procedure.
Amobarbital is a drug that is a barbiturate derivative. It has sedative-hypnotic properties. It is a white crystalline powder with no odor and a slightly bitter taste. It was first synthesized in Germany in 1923. It is considered a short to intermediate acting barbiturate. If amobarbital is taken for extended periods of time, physiological and psychological dependence can develop. Amobarbital withdrawal mimics delirium tremens and may be life-threatening. Amobarbital was manufactured by Eli Lilly and Company in the US under the brand name Amytal in bright blue bullet shaped capsules or pink tablets containing 50, 100, or 200 milligrams of the drug. The drug was also manufactured generically. Amobarbital was widely misused, known as "Blue Heavens" on the street. Amytal, as well as Tuinal, a combination drug containing equal quantities of secobarbital and amobarbital, were both manufactured by Eli Lilly until the late-1990s. However, as the popularity of benzodiazepines increased, prescriptions for these medications became increasingly rare beginning in the mid to late-1980s.
The language module or language faculty is a hypothetical structure in the human brain which is thought to contain innate capacities for language, originally posited by Noam Chomsky. There is ongoing research into brain modularity in the fields of cognitive science and neuroscience, although the current idea is much weaker than what was proposed by Chomsky and Jerry Fodor in the 1980s. In today's terminology, 'modularity' refers to specialisation: language processing is specialised in the brain to the extent that it occurs partially in different areas than other types of information processing such as visual input. The current view is, then, that language is neither compartmentalised nor based on general principles of processing. It is modular to the extent that it constitutes a specific cognitive skill or area in cognition.
Carotid endarterectomy is a surgical procedure used to reduce the risk of stroke from carotid artery stenosis. In endarterectomy, the surgeon opens the artery and removes the plaque. The plaque forms and thickens the inner layer of the artery, or intima, hence the name of the procedure which simply means removal of part of the internal layers of the artery.
Transcranial Doppler (TCD) and transcranial color Doppler (TCCD) are types of Doppler ultrasonography that measure the velocity of blood flow through the brain's blood vessels by measuring the echoes of ultrasound waves moving transcranially. These modes of medical imaging conduct a spectral analysis of the acoustic signals they receive and can therefore be classified as methods of active acoustocerebrography. They are used as tests to help diagnose emboli, stenosis, vasospasm from a subarachnoid hemorrhage, and other problems. These relatively quick and inexpensive tests are growing in popularity. The tests are effective for detecting sickle cell disease, ischemic cerebrovascular disease, subarachnoid hemorrhage, arteriovenous malformations, and cerebral circulatory arrest. The tests are possibly useful for perioperative monitoring and meningeal infection. The equipment used for these tests is becoming increasingly portable, making it possible for a clinician to travel to a hospital, to a doctor's office, or to a nursing home for both inpatient and outpatient studies. The tests are often used in conjunction with other tests such as MRI, MRA, carotid duplex ultrasound and CT scans. The tests are also used for research in cognitive neuroscience.
In the field of neurology, temporal lobe epilepsy is an enduring brain disorder that causes unprovoked seizures from the temporal lobe. Temporal lobe epilepsy is the most common type of focal onset epilepsy among adults. Seizure symptoms and behavior distinguish seizures arising from the medial temporal lobe from seizures arising from the lateral (neocortical) temporal lobe. Memory and psychiatric comorbidities may occur. Diagnosis relies on electroencephalographic (EEG) and neuroimaging studies. Anticonvulsant medications, epilepsy surgery and dietary treatments may improve seizure control.
Frontal lobe epilepsy (FLE) is a neurological disorder that is characterized by brief, recurring seizures arising in the frontal lobes of the brain, that often occur during sleep. It is the second most common type of epilepsy after temporal lobe epilepsy (TLE), and is related to the temporal form in that both forms are characterized by partial (focal) seizures.
A watershed stroke is defined as a brain ischemia that is localized to the vulnerable border zones between the tissues supplied by the anterior, posterior and middle cerebral arteries. The actual blood stream blockage/restriction site can be located far away from the infarcts. Watershed locations are those border-zone regions in the brain supplied by the major cerebral arteries where blood supply is decreased. Watershed strokes are a concern because they comprise approximately 10% of all ischemic stroke cases. The watershed zones themselves are particularly susceptible to infarction from global ischemia as the distal nature of the vasculature predisposes these areas to be most sensitive to profound hypoperfusion.
The lateralization of brain function is the tendency for some neural functions or cognitive processes to be specialized to one side of the brain or the other. The median longitudinal fissure separates the human brain into two distinct cerebral hemispheres, connected by the corpus callosum. Although the macrostructure of the two hemispheres appears to be almost identical, different composition of neuronal networks allows for specialized function that is different in each hemisphere.
Anterior temporal lobectomy (ATL) is the complete or partial removal of the anterior portion of the temporal lobe of the brain. The exact boundaries for removal can vary slightly in practice and between neurosurgeons. It is a treatment option for temporal lobe epilepsy for those in whom anticonvulsant medications do not control epileptic seizures, and who have frequent seizures, and who additionally qualify based on a WADA test to localize the dominant hemisphere for language module.
Epilepsy surgery involves a neurosurgical procedure where an area of the brain involved in seizures is either resected, ablated, disconnected or stimulated. The goal is to eliminate seizures or significantly reduce seizure burden. Approximately 60% of all people with epilepsy have focal epilepsy syndromes. In 15% to 20% of these patients, the condition is not adequately controlled with anticonvulsive drugs. Such patients are potential candidates for surgical epilepsy treatment.
Dysprosody, which may manifest as pseudo-foreign accent syndrome, refers to a disorder in which one or more of the prosodic functions are either compromised or eliminated.
Aprosodia is a neurological condition characterized by the inability of a person to properly convey or interpret emotional prosody. Prosody in language refers to the ranges of rhythm, pitch, stress, intonation, etc. These neurological deficits can be the result of damage of some form to the non-dominant hemisphere areas of language production. The prevalence of aprosodias in individuals is currently unknown, as testing for aprosodia secondary to other brain injury is only a recent occurrence.
In human neuroanatomy, brain asymmetry can refer to at least two quite distinct findings:
Juhn Atsushi Wada was a Japanese–Canadian neurologist known for research into epilepsy and human brain asymmetry, including his description of the Wada test for cerebral hemispheric dominance of language function. The Wada Test remains the gold standard for establishing cerebral dominance and is conducted worldwide prior to epilepsy surgery.
Drug-resistant epilepsy (DRE), also known as refractory epilepsy, intractable epilepsy, or pharmacoresistant epilepsy, is diagnosed following a failure of adequate trials of two tolerated and appropriately chosen and used antiepileptic drugs (AEDs) to achieve sustained seizure freedom. The probability that the next medication will achieve seizure freedom drops with every failed AED. For example, after two failed AEDs, the probability that the third will achieve seizure freedom is around 4%. Drug-resistant epilepsy is commonly diagnosed after several years of uncontrolled seizures, however, in most cases, it is evident much earlier. Approximately 30% of people with epilepsy have a drug-resistant form.
References
- ↑ "Wada Test - Cleveland Clinic". Cleveland Clinic.
- ↑ Loring, D. W. (1997). "Neuropsychological evaluation in epilepsy surgery". Epilepsia. 38 (Suppl 4): S18–23. doi: 10.1111/j.1528-1157.1997.tb04535.x . PMID 9240237.
- ↑ Hermann B (2005). "Wada test failure and cognitive outcome". Epilepsy Currents. 5 (2): 61–2. doi:10.1111/j.1535-7597.2005.05206.x. PMC 1176310 . PMID 16059438.
- ↑ Luria, Aleksandr Romanovich (1980). Higher Cortical Functions in Man. Translated by Haigh, Basil (2nd ed.). New York, NY: Basic Books Inc. p. 98. ISBN 0-465-02960-4.
- ↑ Loring, D.W., Meador, K.J., Lee, G.P., King, D.W. (1992). Amobarbital Effects and Lateralized Brain Function: The Wada Test. New York: Springer-Verlag.
- ↑ Wada J (1949). "A new method for the determination of the side of cerebral speech dominance. A preliminary report of the intra-carotid injection of sodium amytal in man". Igaku to Seibutsugaki, Tokyo. 14: 221–222.
- ↑ Wada J (1997). "Youthful Season Revisited". Brain and Cognition. 33 (1): 7–10. doi:10.1006/brcg.1997.0879. PMID 9056271. S2CID 5530070.
- ↑ Andrew-Gee, Eric (4 May 2023). "Doctor Juhn Wada revolutionized epilepsy surgery (Obituary)". The Globe and Mail. Retrieved 29 December 2023.
- ↑ Loring, David; Meador, Kimford. "History of the Wada Test" (PDF). Oxford Handbook of History of Clinical Psychology.
- ↑ Here's to Future Days (2009) , retrieved 2019-02-03
- ↑ Here's to Future Days (2009) , retrieved 2019-02-03