The history of human neuropsychology

Reports of clinical observations of impairments of human mental functions that can be traced back to brain damage or dysfunction date to centuries ago. However, the naissance of neuropsychology as a scientific discipline is much more recent, dating to the 19th century. A most relevant observation was Paul Broca's report that damage to a frontal premotor region in the left hemisphere causes a deficit of spoken language (aphasia). Starting from this finding, other disorders brought about by brain damage were described, with impairments of perception and object recognition (agnosia), behavioral control, decision making, reasoning and intelligence, movement planning (apraxia), spatial orientation and attention, and memory (amnesia). The early study of individual patients with outstanding clinically apparent deficits (“single cases”) was followed by the investigation of groups of patients, using standardized psychometric tests, and statistical procedures of data analysis. In the second half of the 20th century neuropsychology became an independent scientific discipline, and, starting from the early 1960s, with its own scientific journals (Neuropsychologia, Cortex). In humans the correlation between behavioral deficits on the one hand and the localization of the responsible cerebral lesion on the other hand was initially based on post mortem autoptic findings. Beginning in the late 1930s also cortical brain stimulation of patients during awake surgery provided information about the localisation of cerebral functions. Starting from the late 1970s a variety of non-invasive methods for visualizing in vivo the brain became available for many patients. Neuropsychology, with the investigation of the disorders of higher mental functions caused by brain damage, has contributed both to the understanding of the neural and functional architecture of the mind, and to the diagnosis and rehabilitation of the disorders of its multiple component processes.