“When the history of medicine in the post-colonial era in West Africa is written, the name of B. O. Osuntokun will figure large, as a man of great talent, of prodigious application, and as a tireless advocate of the study of neurology in the tropics.”
— The Independent, UK
The evolution of neurological science in Africa, and the global understanding of tropical neurological disorders, cannot be fully told without acknowledging the monumental legacy of Professor Benjamin Oluwakayode Osuntokun. At a time when tropical medicine was often treated as peripheral to mainstream scientific discourse, he demonstrated that African populations, diets and environments could illuminate fundamental truths about human health.
Osuntokun was among the first to rigorously study and explain how neurological diseases manifest and spread in tropical regions. Through his groundbreaking work in Nigeria and beyond, he established that neurological disease in resource-limited settings could not be properly understood without examining living conditions and broader socio-economic realities.
The impact of that insight continues to influence policies and approaches to neurology and public health across the world. Today, his work is cited not only in neurology textbooks but also in discussions on food security, preventive medicine and global health equity.
Strides in excellence
Osuntokun’s pioneering efforts produced five major, paradigm-shifting outcomes. First, they led to the discovery of the cause of tropical ataxic neuropathy (TAN), a debilitating neurological syndrome prevalent in the tropics. His observation that many affected communities in Nigeria subsisted on a monotonous diet of poorly processed cassava, combined with his careful definition of the disease’s diagnostic criteria, marked a major breakthrough in tropical medicine.
Second, his work compelled a fundamental rethinking of how neurological disease is defined and studied. Osuntokun effectively reframed neurology, expanding it beyond genetics and infection to include nutrition, environment and social context. Third, his research bridged African medical challenges with international science, ensuring that tropical neurological diseases received global attention. Fourth, it directly influenced dietary practices and public health policies in Nigeria and other tropical countries. Fifth, it placed Nigeria firmly on the global map of medical science.
So erudite and exceptional was Osuntokun that three giants of Nigeria’s postcolonial medical landscape – Professors Adeoye Lambo, Oladipo Akinkugbe and Kayode Oyediran – described him as the “Marco Polo of African neurology.”
Auspicious beginnings
Benjamin Oluwakayode Osuntokun was born in 1935 in Ilawe-Ekiti, in present-day Ekiti State. Family accounts describe his birth as precarious, surrounded by both physical and spiritual uncertainty. This was followed, however, by a childhood of remarkable intellectual sharpness, which quickly became evident at school.
He began his education at Holy Trinity School, Ilawe-Ekiti, before gaining admission to the prestigious Christ’s School, Ado-Ekiti. There, Osuntokun distinguished himself not only academically but also in sport, earning a reputation as a gifted all-rounder whose sharp intellect was matched by physical agility. He completed his secondary education with distinction.
In 1956, he entered University College, Ibadan, Nigeria’s first medical school and, at the time, a college of the University of London. The training was demanding and exacting, modelled closely on British standards. He graduated in 1961 with honours, emerging as part of a pioneering generation of Nigerian doctors tasked with shaping a national medical identity in the aftermath of colonial rule.
Path to prominence
Following his outstanding academic performance, Osuntokun was selected in 1963 to join Professor Harold Scarborough’s medical unit in Cardiff, United Kingdom. The experience exposed him to the best traditions of British clinical medicine and enabled him to cultivate professional relationships that later supported his international collaborations.
He subsequently trained in neurology at Newcastle upon Tyne, under the renowned Professor Henry Miller. This was followed by further specialist training at the National Hospital, Queen Square, London, arguably the most prestigious neurological institution in the world. At a time when few Africans were entering neurology, and even fewer were encouraged to pursue academic leadership, Osuntokun distinguished himself through clinical excellence and intellectual independence.
In 1966, just five years after graduating in medicine, he returned to Nigeria as a consultant neurologist at University College Hospital, Ibadan, where he rose rapidly. By 1970, he had been awarded a personal professorship, a rare academic honour reserved for scholars of exceptional distinction, making him one of the youngest professors of medicine in the country.
Redefining tropical neurology
Despite an increasingly demanding academic and clinical workload, Osuntokun insisted that medicine must engage directly with the lived realities of patients. Thus, rather than confining his work to lecture theatres and hospital wards, he ventured into rural communities, observing patterns of disease that had long been ignored or misunderstood.
This approach paved the way for his most influential work. In his observations of patients in parts of south-western Nigeria who presented with progressive gait instability, visual impairment, sensory loss and weakness, he noted that their condition did not fit neatly into known neurological categories. Instead of dismissing it as idiopathic or rare, Osuntokun investigated relentlessly.
He identified commonalities not only in symptoms but also in diet -specifically, chronic reliance on inadequately processed cassava. Through clinical examination, epidemiological surveys and biochemical analysis, he demonstrated that prolonged exposure to cyanogenic compounds from poorly processed cassava, a staple food in many households, could result in a distinctive form of neurological damage now recognised as tropical ataxic neuropathy.
That proved to be a watershed moment with far-reaching implications. His findings influenced food processing practices, public health education and neurological research worldwide. So distinctive were the clinical features he described that aspects of the condition entered medical literature as Osuntokun’s syndrome.
Over the course of his career, Osuntokun authored more than 300 scientific papers spanning neurology, nutrition, epidemiology and tropical medicine. He also made substantial contributions to the study of cerebrovascular disease, epilepsy, diabetic neuropathy, biological psychiatry, Alzheimer’s disease and medical education. As a former colleague once observed, he conducted detailed studies of “any clinical problem that he encountered, to a standard that has yet to be matched in Nigeria.
Teacher, administrator and builder of institutions
Despite widespread international recognition, Osuntokun chose to remain in Ibadan. While many of his contemporaries sought permanent positions abroad, he committed himself to building capacity at home. As a teacher, he trained generations of Nigerian and African doctors, many of whom later became consultants, professors and leaders in medicine.
In 1974, he was appointed dean of the Faculty of Medicine during a turbulent period, navigating the expansion of medical education under military rule. Later, in 1985, he became chief medical director and chief executive of University College Hospital, Ibadan, where he balanced clinical leadership with institutional reform.
But his influence extended well beyond Nigeria. He served on World Health Organisation expert committees, acted as a consultant to international bodies, and became a founding member of the Pan-African Association of Neurological Sciences, advocating for the recognition of tropical neurology as a vital and legitimate field of study.
Awards, recognitions and legacy
Professor Osuntokun’s contributions earned honours commensurate with his impact. In 1984, he received the Nigerian National Order of Merit, the country’s highest academic distinction, becoming only its second recipient after Professor Adeoye Lambo. He was also awarded the national honour of Officer of the Order of the Federal Republic (OFR).
Internationally, he broke new ground as the first African examiner for the Royal College of Physicians in the United Kingdom and the first African Visiting Professor at the Royal Postgraduate Medical School, Hammersmith Hospital. His scholarly output and professional standing placed him among the most respected neurologists of his generation.
Professor Benjamin Oluwakayode Osuntokun died in 1995 at the age of 60, leaving behind a body of work that many could not accomplish in a century. Even in death, his commitment to medical education lingers. He bequeathed a significant portion of his estate to the University of Ibadan to endow professorships in medicine and ophthalmology, honouring both himself and his wife, Professor Olabopo Osuntokun, a distinguished ophthalmologist. His personal library was also distributed among academic institutions, and medical prizes were established in his name.
