Le diagnostic de la maladie de parkinson repose sur la mise en évidence d’un syndrome parkinsonien associé à au moins 2 critères « supports ».
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Diagnosis of Parkinson’s disease

The diagnosis of Parkinson’s disease is made after eliminating other pathologies that may give rise to the same initial symptoms, such as Wilson’s disease in young subjects, vascular lesions or hydrocephalus more rarely.

Parkinson’s disease combines a parkinsonian syndrome with at least 2 of 4 other criteria:

  • Improvement in Parkinson’s syndrome symptoms with dopaminergic treatment
  • The appearance of abnormal involuntary movements (dyskinesias) after many years of dopamine treatment
  • A unilateral or asymmetric resting tremor
  • A reduction (hyposmia) or even complete disappearance (anosmia) of the sense of smell.

Patients may also present ‘non-motor’ symptoms such as intestinal problems, apathy and REM sleep disorders.

At the Institut du Cerveau

A number of recent studies, in particular those carried out by Marie VIDAILHET and Stéphane LEHERICY’s team at the Institut du Cerveau, have shown that the “non-motor” symptoms of Parkinson’s disease occur at an early stage, beginning before the motor symptoms. These clinical signs could therefore be very good diagnostic markers, and could even be used to prognose the progression of the disease. In the ICEBERG study, the team looked at REM sleep disorders and eye movements.

This study also identified a marker of the progression of the loss of dopaminergic neurons, neuro-melanin, visible on MRI. This protein protects neurons by capturing toxic molecules such as iron.


MRI performed by the CENIR imaging platform at the Institut du Cerveau – ICM. Quantity of neuromelanin observed by MRI in the substantia nigra. (Left: healthy individual, centre: patient in early stages of Parkinson’s disease, right: patient with long-standing Parkinson’s disease).

There is a decrease in neuromelanin in patients that increases over time, due to the degeneration of dopaminergic neurons characteristic of Parkinson’s disease.