Table 1.

Clinical Evaluation of Lafora Disease

Evaluation TypeAt OnsetLater in Disease Course
General physical examination, including liver and spleen sizesNormalNormal
Neurologic examination, including fundi and reflexesNormalDysarthria, ataxia, spasticity; fundi remain normal
Mental state examinationVisual hallucinations (epileptic), depressed mood, cognitive deficitsIncreased hallucinations, agitation, and dementia with predominantly frontal cognitive impairment affecting mainly performance ability and executive function
EEGNormal or slow background, loss of α-rhythm and sleep features; photosensitivity is commonSlow background, paroxysms of generalized irregular spike-wave discharges with occipital predominance, and focal, especially occipital, abnormalities
Visual, somatosensory, and auditory brain stem evoked potentialsHigh-voltage visual and somatosensory evoked potentialsAmplitudes may return to normal size; prolongation of brain stem and central latencies
Nerve conduction studiesNormalNormal
MRI of the brainNormalNormal or atrophy 1
Proton MR spectroscopy of the brainData not availableReduced NAA/creatine ratio in frontal and occipital cortex, basal ganglia, and cerebellum; reduced NAA/myoinositol ratio in frontal gray and white matter; reduced NAA/choline ratio in cerebellum 2
Transcranial magnetic stimulation (TMS)Not applicableDefective short intracortical inhibition(SICI): inhibition at ISI 6 ms and ISI 10 ms;
Defective long interval cortical inhibition (LICI)

No significant correlation observed with disease evolution


At least two years after onset of symptoms

From: Progressive Myoclonus Epilepsy, Lafora Type

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Pagon RA, Adam MP, Ardinger HH, et al., editors.
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