Where We’ve Been/Where We’re Headed
In 1964 Horwitz and coworkers presented a paper at an American Psychiatric Association meeting describing two extraordinary identical twin brother savants whose calendar calculating and memory abilities remain as astonishing today as they were then. The twins had a calendar calculating span that extended over 40,000 years. They also remembered the weather for every day of their adult life. They traded 20 digit prime numbers for amusement but could not do the simplest of arithmetic. A discussant noted: “The importance, then, of the Idiot 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.”
Some things have clearly changed in that intervening 36 years. First, in the interest of accuracy and dignity, savant syndrome has appropriately replaced the outdated term idiot savant. Second, the movie Rain Man, which incidentally depicted some of those twin’s actual abilities including the toothpick scene, performed a massive public educational service with respect to both savant syndrome and autism, along with being an admirable and entertaining production in its own right. It made the term autistic savant a household word, and did so in an accurate and sensitive fashion.
But beyond those useful advances, where are we now, 36 years later, in better understanding and explaining the “challenge to our capabilities” that the savant presents? Is the savant still a “landmark to our ignorance” about how the brain works, or have we made some progress in better understanding this marvelous mystery? No model of brain function, including memory, will be complete until it can fully incorporate, and account for, this remarkable, jarring juxtaposition of ability and disability. This paper is a brief look at where we have been, where we are, where we are heading in the search to understand and explain the savant. And it examines as well the vast implications such explanations might have for better understanding normal brain function, brain restoration and repair, and, perhaps, hidden potential within us all.
Where we have been
Dr. Benjamin Rush, the father of American Psychiatry, provided one of the earliest reports of savant syndrome in 1789 when he described in detail the lightning calculating ability of Thomas Fuller “who could comprehend scarcely anything, either theoretical or practical, more complex than counting.” When Fuller was asked how many seconds a man had lived who was 70 years, 17 days and 12 hours old he gave the correct answer of 2,210,500,800 in 90 seconds, even correcting for the 17 leap years included.
The term idiot savant itself, however, was coined by Dr. J. Langdon Down in 1887 and remained the name for this extraordinary condition for the next 100 years. In a series of lectures that year before the Medical Society of London, Down (who is better known for having described Down’s Syndrome), recounted his 30 year experience as Superintendent of the Earlswood Asylum during which time he had encountered some fascinating cases that demonstrated a striking juxtaposition of superiority and deficiency in the same patients. Among the 10 cases he described in colorful detail in were the characteristic musical, artistic, mathematical and mechanical skills, coupled with phenomenal memory, which have so unfailingly typified the savant syndrome for these past 113 years. Dr. Down meant no harm by the term “idiot”, and in fact he apologized for having to apply it–“I have no liking for the term. It is so frequently a name of reproach”, he cautioned. But at that time the term idiot was an accepted scientific term for IQ below 70 and Down combined that with the word savant, or “knowledgeable person,” derived from the French savoir meaning to know.
While descriptive, the term was actually a misnomer since almost all reported cases occur in persons with IQ above 40. In the interests of accuracy and dignity the term savant syndrome has been substituted and is widely used. It is preferable to autistic savant since, as will be shown, only about one-half of persons with savant syndrome are autistic and the other half have other developmental disabilities or other forms of central nervous system injury or disease
What do we know? After more than a century of observation and study now, we do know this:
- The condition is rare occurring in about one in ten persons with Autistic Disorder and about 1:2000 in other forms of developmental disability. Since other forms of DD are more frequent than autism as it turns out about 50% of savants are autistic and 50% have other forms of developmental disability or brain injury or illness. Thus not all autistic persons are savants, and not all savants are autistic.
- Males outnumber females approximately 6:1
- Savant skills occur in an exceedingly narrow range of abilities, which is remarkable considering all the abilities in the human repertoire. They include Music, usually performing, most often piano, with perfect pitch although composing in the absence of performing has been reported; art, usually drawing, painting or sculpting; calendar calculating (an obscure skill in most non-disabled persons); mathematics including lightning calculating or ability to compute prime numbers, for example, typically without other simple arithmetic skills such as multiplication or addition; and mechanical or spatial skills. Some other special skills have been reported including prodigious language facility (polyglot savant); map memorizing; unusual sensory discrimination abilities in smell, touch or vision; perfect appreciation of passing time without knowledge of or access to a clock face; and outstanding knowledge in specific fields such as neurophysiology, statistics, history, or navigation, for example.
- The skills exist over a wide spectrum of abilities ranging from splinter skills, to talented, to finally prodigious skills. The latter level—specific abilities so advanced they would be remarkable even if they were to occur in a non-disabled person—is very rare, with perhaps only 20 to 30 such persons living worldwide at the present time. In most instances a single special skill exists but in some cases multiple skills occur.
- Whatever the special skill, they are always coupled with a phenomenal memory within the skill area itself and may extend to unrelated trivia such as dates, sports scores, ZIP codes, license plate numbers etc. The memory is of a special type–very, very narrow but exceedingly deep within its narrow confines as described in detail below.
- The skills tend to be right hemisphere in type—non symbolic, artistic, concrete, directly perceived—in contrast to left hemisphere skills that are more sequential, logical and symbolic, including language specialization.
- The incidence of the triad of blindness, mental handicap and musical genius is conspicuously high among savants, especially when considering the rarity of each of those single circumstances themselves. Throughout the past century, and at the present time, such instances of prodigious musical savants occur with curious frequency.
- Savant Syndrome can be congenital, and existent at birth, or can be acquired following brain injury or disease later in infancy, childhood or adult life
- Savant skills characteristically continue, rather than disappear and with continued use or practice the special abilities either persist and the same level or actually increase. In almost all cases there is no dreaded tradeoff of special skills with exposure to or acquisition of greater language, socialization, or daily living skills. Instead, the special skills often serve as a conduit toward normalization with an actual increase in such language, social and daily living skills without the feared loss of special abilities such as is reported to have occurred in the often quoted case of Nadia, a childhood artist savant who lost her special abilities as she moved into a more formal education setting and as language acquisition improved.
- No single theory has emerged thus far that can explain all savants.
Newer findings and discoveries
How do they do it?
One important bottom line question surrounding the savant is: How do they do it? Over this past century numerous theories have been put forth but no single theory can explain all savants. Those theories have included eidetic imagery or the related but separate phenomenon generally called photographic memory; inherited skills; sensory deprivation and sensory isolation; a highly developed rote memory; and compensation and reinforcement to offset lack of more general capacity or intelligence. There are problems with each of those theories. Formal testing for eidetic imagery shows that phenomenon to be present in some, but certainly not all savants, and when present it may exist more as a marker of brain damage than being central to savant abilities. Two studies, one with 25 savants and another with a sample of 51 showed relatives with special skills or abilities in some cases but certainly not in all; another study of 23 relatives of carefully studied savants found only one family member with special skills. A number of studies, particularly with calendar calculating and musical skills, have shown savant abilities extend well beyond memorization alone as accounting for the special abilities and that literal rote memory alone does not provide a basis for savant skills.
Left brain injury and right brain compensation
One theory that consistently provides an increasingly plausible explanation for savant abilities in many cases is left brain injury with right brain compensation. In 1980 Brink presented a case of a normal 9 year old boy who was left mute, deaf and paralyzed by a gunshot wound to the left hemisphere. Following that injury, unusual savant-like (acquired savant) mechanical skill emerged, presumably from the undamaged right hemisphere. Tanguay pointed out that the skills most often seen in autisic savants are those associated with right hemisphere functions, and the skills most lacking tend to be associated with the left hemisphere. Rimland also highlighted the simultaneous nature of right brain activities in contrast to the sequential nature of left brain activities in the autistic savant. A number of cases have been reported with documented left hemisphere damage on imaging studies such as CAT scans, correlated with corresponding findings on neuropsychological testing.Even before CAT scans and MRI techniques were available, as early as 1975, pneumoencephalograms demonstrated left hemisphere abnormalities, particularly in the temporal lobe areas, in 15 of 17 autistic patients, four of whom had savant skills in music or mechanical abilities. A 1999 PET study showed low serotonin synthesis in the left hemisphere of persons with autistic disorder and neuropsychological tests also confirmed left hemisphere deficits in these individuals. Other more recent studies will be outlined in more detail below. The observation that most savant skills and abilities are of a type and nature associated with right brain capacity is consistent with such left brain damage and right brain compensation.
Why the disproportionate Male:Female ratio?
Adding strength to those the left hemisphere damage findings, and providing some evidence to explain the disproportionately high male:female ratio in savant syndrome, is the important work by Geschwind and Galaburda on cerebral lateralization. Citing a wide variety of human and animal studies, these researchers have pointed out that the left hemisphere normally completes its development later than the right and thus is subjected to prenatal influences, some of the detrimental, for a longer period of time. In the male fetus, circulating testosterone, which can reach very high levels, can slow growth and impair neuronal function in the more vulnerable left hemisphere, with an actual enlargement and shift of dominance favoring talents associated with the right brain, the kind of skills seen in savants. This same high male:female ratio is seen in dyslexia, delayed speech, stuttering, and hyperactivity, and in autism itself. It also accounts for the higher incidence of left-handedness in males. A “pathology of superiority” was postulated, with compensatory growth in the right brain as a result of impaired development or actual injury to the left brain. Although a left brain injury/right brain compensation theory is not new, earlier theories could not explain why such injury would be more frequent in males than females. This hormonal influence finding may account for that difference.
The special memory of the savant
Whatever the special skills of the savant, remarkable memory of a unique and uniform type welds the condition together. Indeed, extraordinary skills + exceptional memory, both within narrow but spectacular ranges is the savant syndrome. Terms such as automatic, mechanical, concrete, or habit-like have consistently appeared throughout the many descriptions of savants this past 100 years. Down used the term “verbal adhesion” to describe the prodigious memory for facts or materials without comprehension of their meaning. Others have used terms such as “exultation of memory,” “memory without reckoning,” “automatic” or “exaggerated form of habit” to describe this particular form of memory function.
Such unconscious memory suggests what Mishkin and Petri referred to as non cognitive “habit” formation system rather than a cognitive “memory” system. They proposed two different neural circuits for these two different types of memory, a higher level cortico-limbic circuit for so called semantic or cognitive memory, and a lower level, cortico-striatal circuit for the more primitive habit memory which is most often referred to as procedural memory. It may be that the same factors that produce left hemisphere damage, including prenatal hormonal influences in some cases, are instrumental in producing damage to the higher level cognitive memory circuits leaving the savant to rely on the more primitive, but spared, habit memory circuits and thus producing the characteristic right brain skills coupled with habit memory function.
A plausible hypothesis
While no single theory or construct can as yet explain all savants, in my view, based on observations and studies to date, a plausible explanation for many cases of savant syndrome can be summarized thus: In the savant, there is disruption of typical left hemisphere functions as a result of prenatal influences, sometimes sex linked (testosterone), or prenatal or subsequent CNS injury, even later in life, which, in turn, leads to a compensatory migration of neurons and dominance of right hemisphere function. A predilection for simultaneous, non symbolic, literal skills and functions results. Such left hemisphere cortical and/or corpus callosum abnormality is coupled with damage to the higher level cortico-limbic (cognitive) memory circuits, probably arising from those same influences, causing the savant to rely upon and largely be limited to more primitive, lower level cortico-striatal (habit) memory circuits. These cortical and memory circuit injuries together produce the savant’s characteristic cluster of symptoms, capabilities, and unique memory. In talented savants, concreteness and impaired ability to think abstractly are locked in a very narrow band but with constant repetition and practice, the savant is able to produce sufficient coding so that access to some unconscious algorithms can be automatically attained. In the prodigious savant some genetic factors may be operative as well, since practice alone cannot account for access to the vast rules and syntax of music, art or mathematics which is innate to these individuals. Once established, intense concentration, practice, compensatory drives and reinforcement, from family, therapists and caretakers, play important roles in further developing and polishing the extraordinary mix of skill and memory made possible by the unique and idiosyncratic brain functioning.
In 1995 Young carried out the largest study on savants (51 persons) in which, in addition to obtaining family histories, each savant was interviewed and given standardized psychological and neuropsychological tests. She concluded, based on this single largest sample studied in a uniform manner, that the savant is a neurologically impaired individual who shows language and intellectual impairments consistent with autism. Skills are generally rule based, rigid, and highly structured lacking critical aspects of creativity and cognitive flexibility. Preserved neurological capacity to process information related to their skills, a well developed declarative memory, a familial predisposition toward high achievement and support, plus the opportunities for encouragement and support provide a climate for savant skills to develop. In a more recent summary of that work Young and Nettelbeck conclude that literal rote memory alone does not provide a basis for savant skills, not do they represent “separate intelligences” outside the concept of overall general intelligence.
These findings regarding the idiosyncratic cortical and memory circuitry in the savant are supportive of consistent with the cortical damage/memory impairment theories above. Instead of a “pathology of superiority” based on brain areas that are damaged and compensated for elsewhere, Young and Nettlebeck propose that brain areas that are spared are most crucial in accounting for the special skills of savants, rather than the savant relying on brain areas that have compensated for damage elsewhere.
Williams Syndrome and Savant Syndrome
The link between Williams Syndrome and savant syndrome is especially intriguing, In 1961 Williams described a genetic disorder in children that was characterized by mental retardation, distinctive elfin-like facial features, aortic stenosis, elevated calcium levels, autistic like behaviors, and often savant-level, extraordinary musical ability. Dissimilarities, however, include the distinctive outgoing social skills (cocktail personality) and a rich, expansive grammatically complex vocabulary with striking conversation and storytelling skills typically associated with Williams syndrome.
The unusual coexistence of impaired general intellect but spared and even precocious language abilities characteristic of Williams syndrome challenges theories about the usual association between language and cognition. Of further interest in these persons with Williams syndrome features, which include the precocious musical skills typically seen in savant syndrome, is the presence of a specific genetic defect on chromosome 7 as the genetic, etiologic factor. This defect, which impairs elastin production, is believed by some investigators to account for the cardiovascular and neurodevelopmental changes seen in Williams syndrome.
So uniform and striking are the musical skills in Williams syndrome, that a series of music camps have developed at several sites in the United States specifically for Williams syndrome patients as a treatment and developmental approach to these individuals, and a residential component to these camps for year-round teaching and training is being developed as well.
A Significant Discovery: New savant-like artistic and other skills in dementia patients
A particularly intriguing recent finding regarding savant skills is a 1998 report by Miller and coworkers who described five patients with frontotemporal dementia (FTD) who acquired new artistic skills with the onset of dementia of this particular form. Consistent with characteristics and traits in savants, the creativity in these five older, adult patients was visual, not verbal; the images were meticulous copies that lacked abstract or symbolic qualities; episodic memory was preserved but semantic memory was devastated; and there was intense, obsessive preoccupation with the art skills. Imaging studies showed a predominance of dominant-hemisphere (left-brain) injury consistent with the savant studies outlined above.
The authors of this study hypothesized that selective degeneration of the anterior temporal and orbitofrontal cortex (particularly in the left hemisphere) decreased inhibition of visual systems involved with perception, thereby enhancing artistic interest and abilities. Kapur called this process “paradoxical functional facilitation” and he speculated it is this process which accounts for unexpected behavioral improvement in some persons following brain injury. This would represent a particular form of brain function compensation in undamaged areas of the cortex and other areas and could be part of the right brain compensatory process in savants as well as in these five dementia patients.
In an expansion of that work, Miller and coworkers describe seven additional such FTD patients who acquired or sustained new visual or musical talents despite the progression of their dementia. No Alzheimer’s patient with that form of dementia observed during the same period exhibited similar talents (approximately 10% of patients evaluated for Alzheimer’s dementia received a diagnosis of FTD). The 12 FTD patients with these newly emerged or sustained savant-like talents were compared on SPECT imaging and neuropsychological testing to FTD patients without such talent. Nine of the twelve showed asymmetric left-sided SPECT deficits, one bilateral abnormalities (left on MRI, right on SPECT), while two has asymmetric right-sided dysfunction (one of whom was left-handed). The talented group performed better on tasks assessing right frontal lobe functions, but worse on verbal abilities. The authors conclude “Loss of function in the left anterior temporal lobe may lead to the ‘paradoxical functional facilitation’ of artistic and musical skills. Patients with the left-sided temporal lobe variant of FTD offer an unexpected window into the neurological mediation of visual and musical talents.
While the emergence of new savant skills following brain damage from trauma or disease (acquired savantism) early in life has been reported as noted earlier, the uncovering and unfolding of such new savant-like skills in some older, previously non-disabled adults, raises interesting questions about the nature and extent of buried potential in non-disabled individuals. The finding of predominantly left sided damage, and the speculation about paradoxical functional facilitation are items both very pertinent to ongoing savant syndrome research.
SPECT imaging in a 9-year-old artistic savant
Hau, Miller and coworkers, in a article just published, set out to examine common patterns in the lives and artwork of five well-known artistic savants reported earlier (Mind, Yamashita, Yamamoto, Yamamura and Nadia), and to report as well the clinical, neuropsychological and imaging studies on a newly diagnosed 9 year old artistic savant, DB. The researchers describe in detail the “striking parallels” of DB with other artistic savants, particularly Nadia. DB displayed an obsession for one art medium (felt-tipped pen) and one type of subject (cartoon figures). He shows many other typical savant traits, has extraordinary drawing skills and exceptional visual memory. He has had pictures shown at several local museums and in books on children’s art. MRI scan was normal. SPECT (single photon emission tomography) functional imaging showed bilateral increased frontal perfusion with bilateral anterior temporal lobe hypofusion, which was worse on the left than the right. This of course is the same site of pathology implicated in the 12 FTD patients with savant-like skills described above.
In the discussion of these findings, the authors remark on the “remarkable parallels between these artistic savants and the recently described patients with ‘semantic dementia’…..whose reports suggest that in some semantic dementia patients, degeneration of the anterior temporal lobes facilitates, or even precipitates, new visual artistic skills. In some of these patients, artistic interest developed only when the left-sided anterior temporal degeneration was clinically manifest.” They go on to state that such artistic blossoming has been reported across cultures in the United States, Japan and Europe with the unifying feature being that all of these individuals showed degeneration of the left anterior temporal lobe. They conclude: “The anatomic substrate for the savant syndrome may involve loss of function in the left temporal lobe with enhanced function of the posterior cortex.”
Train the talent, or eliminate the defect?
Etiologic considerations aside, what is the best approach to the savant, and his or her special skills. Phillips framed the controversy in 1930 when he stated: “The problem of treatment comes next. The question that arises is one of method, whether is it better to eliminate the defects or train the talent”. While questions of etiology remain, the results, especially in recent years, answer Phillip’s question. The answer: Train the talent and with it some of the ‘defect’ subsides. The special talent, in fact, becomes a conduit toward normalization, using the unique savant skills to help toward more socialization, language acquisition and independence, all, in my experience and in experience reported by a number of other investigators, without any tradeoff or loss of special abilities for those valuable gains in other areas, the case of Nadia notwithstanding.
Nettlebeck and Young summarize it this way: interests of the savant are best served by a balanced educational approach that includes social skills, training, counseling and opportunities for interactions with others, together with encouraging savant skills but not letting them dominate the individual’s life. The goal of dealing with the special skills in the savant is not to eradicate them, monotonous, impractical and frivolous at they might sometimes seem. The goal is rather to put them to good use, creatively and patiently, without fear they will either take over the savant’s life or disappear from it. The skills instead can remain as modes of expression through which others can reach and relate to the savant. Such communication and mentoring can lead to the development of other related skills. There are now a number savants well-known through the media, and books, that demonstrate impressively, particularly over this past decade, how well that conduit toward normalization works and the amazing success that training the talent can have in eliminating the defect.
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 ten years particularly, there have been much progress in explaining this jarring justaposition of severe mental impairment and prodigious mental ability. Many questions remain unanswered, but interest in the fascinating condition is accelerating particularly since the discovery of new savant skills in previously non-disabled older persons with the onset and progression of frontotemporal dementia. This finding has far-reaching implications regarding buried potential, perhaps, in all of us.
Newer functional imaging techniques such as PET or SPECT will help provide insights into brain function, not just brain structure, not only in savant syndrome, but in autistic disorder and other forms of developmental disability as well. Those findings can then be correlated with detailed and standardized neuropsychological testing in larger samples of savants, comparing and contrasting those findings with data from both disabled and non-disabled control groups, including prodigies. The interface between genius, prodigies and savants is especially intriguing and these studies can shed light on the important debate regarding general intelligence v. separate intelligences. Savants provide a unique window into the creative process itself. Certainly from these studies, some of which are already underway, important information can emerge regarding brain function, brain plasticity and CNS compensation, recruitment and repair.
But there is more to savant syndrome than circuitry, neurons, hemispheres and the brain’s marvelous intricacy. Just as those matters hold a rich store of material of scientific interest, there is a rich store as well of human interest stories regarding the power of love, belief, and dedication that the equally remarkable families, caretakers and teachers provide. There is more to human potential than neurons and synapses. It is also comprised of, and propelled along by, the vital forces of reinforcement and encouragement which flow from that unconditional love, belief and determination of those families and friends who care not only for the savant, but care about him or her as well.
Savant Syndrome still remains a “challenge to our capabilities”, but is less now a landmark to our ignorance” about ourselves than 36 years ago. That important inquiry continues, with the prospect of propelling us along further than we have ever been in unraveling the enigma and mystery of these extraordinary people.
Some Pertinent References
- Horwitz, W. A., Kesterbaum, C., and Jarvick, L. Identical twins–“idiot savants”–calendar calculators. American Journal of Psychiatry 1965; 121:1075-79.
- Miller B.L., Cummings, J., Mishkin, F., et al. Emergence of artistic talent in frontotemporal dementia. Neurology. 1998;51:978-982.
- Treffert, D.A. The savant syndrome and autistic disorder. CNS Spectrums. 1999; 4:No. 12: 57-60.
- Treffert D.A. Extraordinary People: Understanding Savant Syndrome Omaha, NE Backinprint.com/iUniverse.com 2000.
- Down, J.L. On Some of the Mental Affections of Childhood and Youth. London, Churchill, 1887.
- Duckett, J. Idiot savants: super-specialization in mentally retarded persons Doctoral Dissertation. University of Texas in Austin, Department of Special Education, 1976.
- LaFontaine, L. Divergent abilities in the idiot savant. Doctoral Dissertation. Boston University in Boston, School of Education, 1974.
- Giray, E. F., and Barclay, A.G. Eidetic imagery: longitudinal results in brain-damaged children American Journal of Mental Deficiency. 1977; 82:311-14.
- Young, R. Savant Syndrome: Processes underlying extraordinary abilities. Unpublished Doctoral Dissertation. University of Adelaide, South Australia, 1995.
- Nettlebeck, T and Young, R Savant Syndrome In International Review of Reseach in Mental Retardation ed. C.M. Glidden New York, Academic Press 1999.
- Brink, T. L. Idiot savant with unusual mechanical ability: an organic explanation American Journal of Psychiatry. 1980;137:250-51.
- Tanguay, P. E. A tentative hypothesis regarding the role of hemispheric specialization in early infantile autism Paper presented at the UCLA Conference on Cerebral Dominance, Los Angeles, 1973.
- Rimland, B. Infantile Autism: The syndrome and its implications for a neural theory of behavior. New York, Appleton-Century-Crofts, 1964.
- Hauser, S. L., DeLong, R. G., and Rosman, N. P. Pneumographic findings in the infantile autism syndrome. 1975. Brain;98:667-88.
- DeLong, R. G. Autism: New data suggest a new hypothesis Neurology. 1999; 52:911-16.
- Geschwind, N. and Galaburda, A. M. Cerebral lateralization: Biological Mechanisms, Associations and Pathology. Cambridge, MA:MIT Press, 1987.
- Mishkin, M and Petri, H. L. Memories and habits: Some implications for the analysis of learning and retention. In Neuropsychology of Memory, eds. L. R. Squire and N. Butters. New York, Guildford Press, 1984.
- Williams, J., Barratt-Boyes, and Lowe, J. Supravalvular aortic stenosis. Circulation. 1961; 24:1311-18.
- Hou, C., Miller, B.L., Cummings, J. L. et al Artistic savants. Neuropsychiatry, Neuropsychology and Behavioral Neurology 13:29-38, 2000.
- Selfe, L. Nadia: A Case of Extraordinary Drawing Ability in an Autistic Child London, Academic Press 1977.