No model of brain function, including memory, will be complete until it can account for, and fully incorporate, the rare but spectacular condition of savant syndrome. In the past decade, particularly, much progress has been made towards explaining this jarring juxtaposition of ability and disability, but many unanswered questions remain. However, interest in this fascinating condition is accelerating, especially since the discovery of savant-type skills in previously unimpaired older persons with FTD and other acquired savant instances. This finding has far-reaching implications regarding buried potential in some or, perhaps, all of us.
Advanced technologies will help in those investigations. Computed tomography (CT) and MRI provide stunningly high-resolution images of all the brain architecture, surface and deep, permitting detailed inspection of brain structure. However, studies of brain function, such as positron emission tomography (PET), single photon emission CT (SPECT) or functional MRI, are much more informative regarding savant syndrome, and, indeed, autism itself, since these newer techniques provide information about the brain at work, rather than simply viewing brain architecture. An even more recent imaging technique is diffusion tensor imaging, based on measuring water flow within neurons, which provides graphic images of brain connectivity between the brain hemispheres, within the brain hemispheres and between upper cortical and lower brain stem structures. A related technique, diffusion tensor tracking, provides a direct visual view of the actual fibre tracks, or wiring, of the brain in great detail.
One of the drawbacks to savant functional imaging research, especially art and music performance skills, has been the necessary immobilization of the subject when doing the imaging. Near-infrared spectroscopy, which measures haemoglobin, uses an infrared cap which the patient can wear while ‘at work’ performing music or painting or drawing, for example. Also there have been many advances in electroencephalographic techniques, including magnetoencephalography, which provides a great deal of additional information beyond the usual electroencephalographic findings.
Detailed, standardized neuropsychological test results can then be correlated with the imaging findings in savants in sufficiently large samples to move away from what have been so many single subject, anecdotal reports. Control groups of non-impaired persons can be assembled to compare and contrast findings in both groups. Beyond that, since the interface between genius, prodigies and savants is an important, and in some ways a very narrow one, those persons should be included also in these multidisciplinary, multimodality, compare and contrast studies. Such studies can shed light on the debate regarding general intelligence versus separate intelligences. Some researchers suggest that savants provide a unique window into the creative process itself. From studies already completed, important information has already emerged regarding brain function, brain plasticity, CNS compensation, recruitment and repair.
Savant syndrome, both in the congenital and acquired types, provides compelling evidence of remarkable brain plasticity. Indeed, brain plasticity will be a central aspect of all neuroscience research in the decades ahead. Until fairly recently, there has been what Dodge (2007)
, in his book The brain that changes itself
, calls ‘neurologic nihilism’. This was a generally pessimistic view of the ability of neuronal tissue to regenerate and rewire itself in the face of injury or disease. The concept of one brain area being ‘recruited’ to take over the function of some other damaged area, paradoxical functional facilitation (Kapur 1996
), is central to explaining savant syndrome. Some argue that the ‘recruitment’ of abilities is actually a ‘release’ phenomenon of already existing
, but dormant, abilities as opposed to the compensatory development of new
skills. In the case of right brain versus left brain capacity, some have referred to that substitution as a release ‘from the tyranny’ of the left, or dominant, hemisphere.
But there is more to savant syndrome than genes, circuitry and the brain's marvellous intricacy. As important as those matters are in terms of scientific interest, there is also much we can learn from savant syndrome from the human interest perspective provided by these remarkable people, and the equally remarkable and dedicated families, caretakers, teachers and therapists who surround them. For human potential consists of more than neurons and synapses. It also comprises, and is propelled along by, the vital forces of encouragement and reinforcement that flow from the unconditional love, belief, support and determination of those families and friends who not only care for the savant, but care about him or her as well.
At a 1964 meeting of the American Psychiatric Association, a discussant concluded, with respect to the ‘calculating twins’, that the importance of the savant ‘lies in our inability to explain him; he stands as a landmark of our own ignorance and the phenomenon of the idiot savant exists as a challenge to our capabilities’ (Horwitz et al. 1965
). But savant syndrome is less now a ‘landmark to our ignorance’ than 44 years ago. More progress has been made in the past 15 years in better understanding and explaining savant syndrome than in the previous 100 years. Also, that important inquiry continues, with the prospect of propelling us along further than we have ever been in unravelling the mystery of these extraordinary people and their remarkable abilities. Moreover, in that process, we can also learn more about ourselves, explore the ‘challenge to our capabilities’ and uncover the hidden potential—the little Rain man—that resides, perhaps, within us all.