Clinical neuropsychology is a subfield of psychology focused on the applied science of brain–behavior relationships. Clinical neuropsychologists apply their research to the assessment, diagnosis, treatment, and rehabilitation of patients with neurological, medical, neurodevelopmental, and psychiatric conditions. The branch of neuropsychology associated with children and young people is called pediatric neuropsychology.
Clinical neuropsychology is a specialized form of clinical psychology focused on research as a focal point of treatment within the field. For instance, a clinical neuropsychologist will be able to determine whether a symptom was caused by a traumatic injury to the head or by a neurological/psychiatric condition. Another focus of a clinical neuropsychologist is to find cerebral abnormalities.
Assessment is primarily by way of neuropsychological tests but also includes patient history, qualitative observation, neuroimaging, and other diagnostic medical procedures. Clinical neuropsychology requires an in-depth knowledge of neuroanatomy, neurobiology, psychopharmacology, and neuropathology.
History During the late 1800s, brain–behavior relationships were interpreted by European physicians who observed and identified behavioral syndromes that were related to focal brain dysfunction.
Clinical neuropsychology is a fairly new practice in comparison to other specialty fields in psychology, with a history going back to the 1960s. Parts of neurology, clinical psychology, psychiatry, cognitive psychology, and psychometrics have all been applied together to create clinical neuropsychology, a practice that is very much so still evolving. The history of clinical neuropsychology is long and complicated due to its ties to so many older practices. Researchers like Thomas Willis, who has been credited with creating neurology; John Hughlings Jackson, who theorized that cognitive processes occurred in specific parts of the brain; Paul Broca and Karl Wernicke, who studied the human brain in relation to psychopathology; and Jean Martin Charcot, who apprenticed Sigmund Freud, who created the psychoanalytic theory, all contributed to clinical medicine, which later contributed to clinical neuropsychology. The field of psychometrics contributed to clinical neuropsychology through individuals such as Francis Galton, who collected quantitative data on physical and sensory characteristics; Karl Pearson, who established the statistics that psychology now relies on; Wilhelm Wundt, who created the first psychology lab; his student Charles Spearman, who furthered statistics through discoveries like factor analysis; Alfred Binet and his apprentice Theodore Simon, who together made the Binet–Simon scale of intellectual development; and Jean Piaget, who studied child development. Studies in intelligence testing made by Lewis Terman, who updated the Binet–Simon scale to the Stanford–Binet Intelligence Scales; Henry Goddard, who developed different classification scales; and Robert Yerkes, who was in charge of the Army Alpha and Beta tests, also all contributed to where clinical neuropsychology is today.
Clinical neuropsychology focuses on the brain and goes back to the beginning of the 20th century. As a clinician, a clinical neuropsychologist offers their services by addressing three steps: assessment, diagnosis, and treatment. The term "clinical neuropsychologist" was first used by Sir William Osler on April 16, 1913. While clinical neuropsychology was not a focus until the 20th century, evidence of brain and behavior treatment and studies are seen as far back as the Neolithic era, when trephination, a crude surgery in which a piece of the skull is removed, was observed in skulls. During World War I, the early term "shell shock" was first observed in soldiers who survived the war. This was the beginning of efforts to understand traumatic events and how they affected people. During the Great Depression, further stressors caused shell shock-like symptoms to emerge. In World War II, the term "shell shock" was changed to "battle fatigue", and clinical neuropsychology became even more involved with attempting to solve the puzzle of people's continued signs of trauma and distress. The Veterans Administration, or VA, was created in 1930, which increased the call for clinical neuropsychologists and, by extension, the need for training. The Korean and Vietnam Wars further solidified the need for treatment by trained clinical neuropsychologists. In 1985, the term "post-traumatic stress disorder", or PTSD, was coined, and the understanding that traumatic events of all kinds could cause PTSD started to evolve.
The relationship between human behavior and the brain is the focus of clinical neuropsychology as defined by Meir in 1974. There are two subdivisions of clinical neuropsychology that draw much focus: organic and environmental natures. Ralph M. Reitan, Arthur L. Benton, and A.R. Luria are all past neuropsychologists who believed in and studied the organic nature of clinical neuropsychology. Alexander Luria is the Russian neuropsychologist responsible for the origination of clinical psychoneurological assessment after WWII. Building upon his originative contribution connecting the voluntary and involuntary functions influencing behavior, Luria further conjoins the methodical structures and associations of neurological processes in the brain. Luria developed the 'combined motor method' to measure thought processes based on the reaction times when three simultaneous tasks are appointed that require a verbal response. On the other side, the environmental nature of clinical neuropsychology did not appear until more recently and is characterized by treatments such as behavior therapy. The relationship between physical brain abnormalities and the presentation of psychopathology is not completely understood but is one of the questions that clinical neuropsychologists hope to answer in time.
In 1861, the debate over human potentiality versus localization began. The two sides argued over how human behavior is presented in the brain. Paul Broca postulated that cognitive problems could be caused by physical damage to specific parts of the brain based on a case study of his in which he found a lesion on the brain of a deceased patient who had presented the symptom of being unable to speak; that portion of the brain is now known as Broca's area. In 1874, Carl Wernicke also made a similar observation in a case study involving a patient with a brain lesion who was unable to comprehend speech; the part of the brain with the lesion is now deemed Wernicke's area. Both Broca and Wernicke believed in and studied the theory of localization. On the other hand, equal potentiality theorists believed that brain function was not based on a single piece of the brain but rather on the brain as a whole. Marie J.P. Flourens conducted animal studies in which he found that the amount of brain tissue damaged directly affected the amount that behavior ability was altered or damaged. Kurt Goldstein observed the same idea as Flourens except in veterans who had fought in World War I. In the end, despite all of the disagreement, neither theory completely explains the human brain's complexity. Thomas Hughlings Jackson created a theory that was thought to be a possible solution. Jackson believed that both potentiality and localization were in part correct and that behavior was made by multiple parts of the brain working collectively to cause behaviors, and Luria furthered Jackson's theory.
Career Neuropsychologists commonly work in hospitals. There are three main variations in which a clinical neuropsychologist may work at a hospital: as an employee, consultant, or independent practitioner. A clinical neuropsychologist working as an employee of a hospital would receive a salary and benefits and have a contract for employment. The hospital is in charge of legal and financial responsibilities for their neuropsychologists. The second option of working as a consultant implies that the clinical neuropsychologist is part of a private practice or is a member of a physicians' group. In this scenario, the clinical neuropsychologist may work in the hospital like an employee of the hospital, but all financial and legal responsibilities go through the group that the clinical neuropsychologist is a part of. The third option is to be an independent practitioner, who works alone and may even have their office outside of the hospital or rent a room in the hospital. In the third case, the clinical neuropsychologist is completely on their own and in charge of their own financial and legal responsibilities.
Assessment Assessments are used in clinical neuropsychology to find brain psychopathologies of the cognitive, behavioral, and emotional variety. Physical evidence is not always readily visible, so clinical neuropsychologists must rely on assessments to tell them the extent of the damage. The cognitive strengths and weaknesses of the patient are assessed to help narrow down the possible causes of the brain pathology. A clinical neuropsychologist is expected to help educate the patient on what is happening to them so that the patient can understand how to work with their own cognitive deficits and strengths. An assessment should accomplish many goals, such as gauging consequences of impairments to quality of life, compiling symptoms and the change in symptoms over time, and assessing cognitive strengths and weaknesses. Accumulation of the knowledge earned from the assessment is then dedicated to developing a treatment plan based on the patient's individual needs. An assessment can also help the clinical neuropsychologist gauge the impact of medications and neurosurgery on a patient. Behavioral neurology and neuropsychology tools can be standardized or psychometric tests and observational data collected on the patient to help build an understanding of the patient and what is happening with them. There are essential prerequisites that must be present in a patient in order for the assessment to be effective: concentration, comprehension, motivation, and effort.
Although assessments have been done manually by neuropsychologists, advances have been made where AI is now being used to help make assessments easier to understand. In the 2010s, machine learning had already made progress, but it was only towards the 2020s that full access to AI led to massive improvements in performance as an assessment tool. Machine learning originally had its first fast advances in 2017, which are reviewed in an academic journal by Frontiers in Aging Neuroscience. They discovered that machine learning was an aid in neuropsychological tests to find out if someone has Alzheimer's, in comparison to whether they find a different cognitive dysfunction within the patient. It is recorded that machine learning has high accuracy in its assessment of individuals who may have cognitive impairment.
Since the 2020s, full implementation of AI for diagnostics has become apparent when its use exists for clinical neuropsychology by using it to primarily assess whether someone has Alzheimer’s. AI has become prevalent for leading in the early diagnosis of discovering whether someone is slowly developing Alzheimer's. It has been noted that machine learning has been more effective in assessment in comparison to human neurologists. Machine learning has been noted as having an accuracy that is not inefficient; the use of support vector machines (SVM) had a quoted accuracy of 77.17%.