Which physical findings are characteristic of frontotemporal lobe dementia with motor neuron disease (FTD/MND)?

Updated: Apr 11, 2017
  • Author: Jasvinder Chawla, MD, MBA; Chief Editor: Jasvinder Chawla, MD, MBA  more...
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Patients with frontotemporal lobe dementia with motor neuron disease (FTD/MND) usually perform poorly on tests of frontal lobe function (ie, Wisconsin card sorting, picture sequencing, verbal fluency tests). Memory is impaired, but less consistently in the mild stages.

Clinical signs of MND usually follow or accompany dementia onset. MND signs include bulbar weakness with dysarthria and dysphagia, limb weakness, muscle wasting and fasciculations, and, of greatest concern, dyspnea.

Akinesia and rigidity are uncommon in this disorder but more common in patients with a longer interval between onset of dementia and neurologic signs (more than 24mo in a Japanese series). This may reflect, in part, the variable involvement of the substantia nigra and other pigmented brainstem nuclei that are observed in roughly 50% of patients at autopsy. This, in turn, may vary between populations (more common in Chamorro Indians).

Moon et al have shown that slow vertical saccades are common in FTD/MND. [20] This may require additional studies in the future to confirm the involvement of the burst neurons in the dorsal midbrain in patients with FTD/MND.

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