Was Neuroscience’s Most Famous Amnesiac, “HM”, A Victim of Medical Error?

By Neuroskeptic | March 5, 2015 2:01 pm

According to a new paper, one of neuroscience’s most famous case-studies came about as a result of a serious medical blunder.

HenryMolaisonHenry Molaison (1926 – 2008), better known as HM, was an American man who developed a dramatic form of amnesia after receiving surgery that removed part of the temporal lobes of his brain. The 1953 operation was intended to treat HM’s epilepsy, but it had the side effect of leaving him unable to form new memories.

The consequences of HM’s surgery are well known – his amnesia was the subject of dozens of scientific papers. But what’s been less discussed is why HM was given such a drastic operation.

According to Francois Mauguière and Suzanne Corkin, the authors of the new paper, the whole thing was a mistake. They argue that HM had a form of epilepsy that can’t be treated by any kind of surgery – and his doctors should have known this, even back in 1953. (Corkin worked with HM for many years and recently published a book about his life, Permanent Present Tense.)

Regarding HM’s diagnosis, Mauguière and Corkin argue that HM almost certainly suffered from idiopathic generalized epilepsy (IGE). A defining feature of IGE is that the seizures do not start from any particular place in the brain. In other forms of epilepsy, there is a focus. The focus is often (although not always) found in the temporal lobe. Surgical removal of such a focus can be an effective treatment. But in IGE, there is no focus.

If Mauguière and Corkin are right, the tissue that was removed from HM’s temporal lobes was perfectly healthy. A sobering thought. What’s more, the authors say that HM’s doctors at the time knew that he probably had no epileptic focus. So why did they cut up his brain?

It appears that the answer lies in a dubious theory that William B. Scoville, the neurosurgeon who proposed the operation, held. Scoville believed that cutting certain brain pathways could ‘raise the seizure threshold’ in the brain, and hence treat any kind of epilepsy, whether or not there was a focus.

Indeed, shortly after operating on HM, Scoville published a brief paper in which he suggested that in the future, surgery might render anti-epileptic drugs obsolete:

Who knows if neurosurgeons may even carry out selective rhinencephalic ablations in order to raise the threshold for all convulsions, and thus dispense with pharmaceutical anticonvulsants?

It’s not clear where Scoville got this idea from, although Mauguière and Corkin suggest that it ultimately derives from the world of psychosurgery – the neurosurgical treatment of mental illness. Psychosurgery was based around the idea that particular surgical lesions could ‘re-balance’ the whole brain (and mind). Scoville was himself an active psychosurgeon.

Overall, Mauguière and Corkin conclude that HM’s surgery was a mistake, even by the standards of the time, and they say that

H.M.’s case will remain as a historical monument in the quest for knowledge about human memory and human epilepsy. The past is past, but we should never see another case H.M.

ResearchBlogging.orgMauguière F, & Corkin S (2015). H.M. never again! An analysis of H.M.’s epilepsy and treatment. Revue neurologique PMID: 25726355

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  • Enzo Tagliazucchi

    Did not read the article but two questions instantaneously come to mind:

    1) Did seizures stop after the resection of temporal lobes? Or did H.M. suffer from epilepsy his whole life?

    2) Even if they mistook IGE for temporal lobe epilepsy, why both hippocampi were resected? Wasn’t intra-cranial electrophysiology used at the time to narrow down the epileptogenic focus?

    • Helmut Laufs

      The answer to your 2nd question is given above: the surgeon pursued his idea that the planned surgery would help ANY case of epilepsy, hence no further search for a focus was performed.

    • Irene

      Huh. Yeah, I’d like to know the answer to the first question, as well. I wonder whether the paper itself says?

      • Silk VanLeer

        Wikipedia says the epilepsy was cured by the procedure.

        • http://blogs.discovermagazine.com/neuroskeptic/ Neuroskeptic

          Here’s what Mauguière and Corkin say:

          “Postoperatively, H.M. continued to have seizures, but they were reported as less frequent than before. His generalized convulsive seizures occurred once every two or three years during the 14 years that followed surgery, while the frequency of absences was, as is often the case, difficult to evaluate, but absences were seen once or twice a day on average.”

          This represents a large drop in the rate of seizures, but HM was still epileptic and still had an abnormal EEG. They go on to say that

          “It is unclear whether the progressive improvement in his epilepsy during the 55 years he survived after the bilateral medial temporal lobectomy could be explained by the operation.”

  • Doc4u

    Beware of anyone holding a knife – unlikely they mean you well.

  • Doc4u

    JFK’s sister.

  • feloniousgrammar

    Well. I’m glad I don’t have the authority to act on a pet thought by removing part of someone’s brain. My impulsive nature really does, truly, appreciate that.

    • Irene

      Agreed, profoundly. The degree of irresponsibility here is astonishing, and points to a god complex on the part of the surgeon. I’d like to believe that’s less common today…

      • feloniousgrammar

        I’d like to believe that, too, but cannot.

        • Irene

          Agreed. :(

          • feloniousgrammar

            But, I think it’s not so much the God Complex (though that can surely be a problem) but corruption and management, especially with guidelines.

  • Helen Phillips

    I thought it was fairly common knowledge that the surgery was erroneous and unnecessary. Certainly my cog psych module portrayed it that way.

    • http://blogs.discovermagazine.com/neuroskeptic/ Neuroskeptic

      True, but there’s a difference between something being a mistake in retrospect, and something being a bad idea even given what was known at the time; I was always taught that HM’s operation fell into the former category but this paper says it was the latter.

      • Helen Phillips

        Ahh – I missed the subtlety. Thanks for that

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Neuroskeptic is a British neuroscientist who takes a skeptical look at his own field, and beyond. His blog offers a look at the latest developments in neuroscience, psychiatry and psychology through a critical lens.

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