Jeremy D. Schmahmann, MD Massachusetts General Hospital Ataxia Center & Lab for Neuroanatomy and Cerebellar Neurobiology - Supported by the MINDlink Foundation

Joined November 2009
282 Photos and videos
With Brad @DickersonLabMGH and @MGHPsychiatry Department celebrating Dr. Janet Sherman, stepping down from directorship of the Psychology Assessment Center which she led superbly for > 35 years, one of the premier clinical, research, training programs in neuropsychology in the US
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Kudos to my former postdoc Catherine Stoodley @LabStoodley for a masterful keynote address on cerebellar circuits and cognition at the Posterior Fossa Society meeting in Copenhagen today.
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Anna Burt presenting her poster to colleagues at ⁦@anpadirect⁩ annual meeting in Providence RI on the cerebellar neuropsychiatric rating scale version 2. Another great ANPA meeting with superb science and wonderful networking in Neuropsychiatry / Behavioral Neurology ⁦
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aging.senate.gov/hearings/fr… See the testimony before Senate on Feb 26th. Grateful to the Senators for their bipartisan commitment to FDA oversight, to bring safe and effective treatments to Americans with rare diseases. The ⁦@US_FDA⁩ needs CPR.
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Schmahmann Lab retweeted
Stimulants in cerebellar ataxia? 🧠 In this patient‑reported study, alertness (95%), fatigue (90%), and executive function (80%) all improved with stimulant therapy—supported by a 26% improvement in PROM‑Ataxia Mental scores. When evaluating cerebellar disorders, screen for fatigue, mental fog, and CCAS features—these may be modifiable and have meaningful QoL impact! @SchmahmannLab movementdisorders.onlinelibr…
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This just out. Broadcast on NPR last night. Real world impact of dysmetria of thought and the cerebellar cognitive affective syndrome. ⁦@NAF_Ataxia⁩ ⁦@anpadirect⁩ ⁦@harvardneuromds⁩ ⁦@MGBResearchNewsradiolab.org/podcast/song-of…
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rdcu.be/eYCXg We examined personal social network metrics in patients with ataxia. Positive relationships, camaraderie, weekly communication, and high levels of emotional support correlate with higher quality of life and better physical function.

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Implication: enhancing emotional support and camaraderie is likely to improve quality of life in patients with ataxia. Kudos to @AmarDhand for developing PERSNET, our RA-now medical student James Concepćion for leading the study, Broadstreet for statistical analysis. @NAF_Ataxia
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CALL TO ACTION: @US_FDA and @DrMakaryFDA need to hear the outrage from @ataxia patients and families about their blocking of the safe drug troriluzole that slows progression in SCA. @naf can share this response. Email your thoughts now to NAF ataxia.org
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Gil was a fabulous friend, colleague and co-author. His epidemiological statistical acumen was deeply impressive as was his commitment to @NAF_Ataxia patients and clinician researchers. We miss him deeply already. The journey continues in his honor.
NAF is saddened by the passing of Dr. Gilbert L’Italien on November 1. Dr. L’Italien was a devoted researcher who advanced programs to develop treatments for Ataxia across several pharmaceutical companies. (1/2)
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Senate is paying attention. FDA sunk Biohaven’s troriluzole yesterday, despite the fact that it slows progression compared to the natural history studies in the US and Europe, according to rigorous statistical analysis of real world evidence. aging.senate.gov/press-relea…
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This is the letter the @WSJ just refused to publish because they did not “have space”. Another snub to @NAF_Ataxia patients and their needs, compounding their distress and the disgrace that is the @FDA @DrMakaryFDA
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International collaboration showcased at the Clinical Trials in Ataxia (CTAX) meeting in Amsterdam. Clinicians, researchers, advocacy groups, pharma, regulators from US and Europe brainstorming about ways to treat and cure the neurodegenerative ataxias. @NAF_Ataxia @CureFA_org
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Check out this forwarded post. It resonates. In my 3 KOL appearances before the neurology committee of the @US_FDA @DrMakaryFDA about troriluzole, have been stunned by their ignorance regarding ataxia, compounded by their arrogance and callous indifference. FDA is broken.
10 Oct 2025
A stunning account from Dr. Patrick Soon-Shiong reveals a catastrophic failure at the FDA, where bureaucratic indifference and potential conflicts of interest are blocking a groundbreaking cancer treatment. His drug, already approved for a form of bladder cancer, is a unique natural protein therapy that activates the body's own immune system (natural killer cells, T-cells). It has shown remarkable long-term results, preserving patients' bladders for over a decade and avoiding radical, high-mortality surgery. Yet, when seeking a simple label expansion for another bladder cancer indication—a logical step—the FDA "Refused to File." In a desperate meeting, Dr. Soon-Shiong confronted two senior reviewers. He posed a heartfelt question: If his own father had bladder cancer, and this safe, approved drug could save his bladder, why wouldn't they give him that chance? Their chilling response: "I don't care." Pushed for rationale, they fell back on outdated dogma: "This is how we've done it for years." They demanded a comparative trial against chemotherapy, which he argued is unethical. Chemotherapy destroys immune memory and carries severe risks, while his treatment offers durable freedom. Weeks later, the hypocrisy was exposed. Johnson & Johnson received a "Priority Review" for a bladder cancer chemotherapy—a treatment with a 1% mortality rate and a 24% rate of devastating low lymphocyte counts. Why the discrepancy? Dr. Soon-Shiong’s drug, despite its breakthrough status, was denied the same priority. This begs the question: Is the "revolving door" between the FDA and Big Pharma putting corporate profits over patient lives? Even with well-intentioned leaders like Bobby Kennedy and Dr. Marty Makary, the entrenched bureaucracy seems immune to both scientific evidence and human compassion. Patients are being left behind, and innovators are being stiff-armed, all while the old, toxic guard is given the red-carpet treatment. This is more than a story of one drug; it's a systemic crisis in American medicine.
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I just provided expert opinion to the @US_FDA committee on Biohaven’s troriluzole. This is going to have to escalate to @RFKJr_Official @HHSGov and @MartyMakary or a senate hearing. FDA is stonewalling a drug that is safe and effective for the US population of @NAF_Ataxia
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More on what the dentate nucleus study in monkeys means for understanding the structure of cognition and its relevance for the cerebellar cognitive affective syndrome ( CCAS):
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Movement of a limb and movement of an idea (Hughlings Jackson) are action oriented and require cerebellar modulation. Executive control of recall requires active manipulation of stored information, reflects dorsal stream processing, and is part of CCAS.
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But episodic memory is a ventral stream function beyond cerebellar control, which is why amnestic dementia is not part of CCAS.
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This lesion-behavior study finally published after a long gestation. Electrolytic lesions of the dentate nuclei bilaterally in monkeys provide the first behavioral confirmation of two key dichotomies of cerebellar organization and function. secure-web.cisco.com/1zR02U_…

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Motor-cognitive dichotomy: Ventral dentate lesions impair working memory and cognitive flexibility - delayed recognition span task (DRST), conceptual set shifting task (CSST) that tap prefrontal cortical function; but spare motor function (Kuypers’ manual dexterity test)
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We also provide empirical evidence supporting our 1993 hypothesis that cerebellum is engaged in dorsal stream cognitive processing (where, action; DRST and CCST), but not ventral stream (what, object identification, recognition memory; delayed non-matching to sample task/DNMS).
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