Physiologie et Sémiologie

Cérébelleuses

Pr Fabien Zagnoli

Hôpital d’Instruction des Armées

Brest

Cervelet:

Régulation du mvt volontaire

Noyaux gris:

Régulation du mvt automatique

Systèmes en dérivation

Rôle Moteur:

• Maintien équilibre

• Régulation du tonus

• Coordination action volontaire

• Programmation motrice

Rôle Non Moteur

Organisation cellulaire

Couche moléculaire

Couche des c. de Purkinje

Couche des grains

LE CORTEX CEREBELLEUX

OLIVE Noyaux du Tronc

Moelle

Noyaux gris

Cervelet

F. GRIMPANTES

GlutamateF. MOUSSUES

Glutamate

Gaba-Taurine

Gaba- NO

Gaba- Adénosine

Golgi

C. Panier

Gaba

Locus Coeruleus (Nad)

Raphé (5HT)

Couche moléculaire

Couche des c. de Purkinje

Couche des grains

LES FIBRES MOUSSUES ET PARALLELES

OLIVE Noyaux du Tronc

Moelle

Noyaux gris

Cervelet

F. MOUSSUES

Glutamate

Gaba-Taurine

Gaba- NO

Gaba- Adénosine

Golgi

C. Panier

Gaba

F. Moussues

Grains

Fibres parallèles

Fibres moussues et parallèles:

Messages divergents et de faible

influence

Potentiels simples

Diffusion de l’information

Coordination du mouvement:

• calcul de la fonction inverse

approchée

Un système diffus

LES FIBRES GRIMPANTES

OLIVE Noyaux du Tronc

Moelle

Noyaux gris

Cervelet

F. GRIMPANTES

Glutamate

Gaba-Taurine

Gaba- NO

Gaba- Adénosine

GolgiGaba

Influx vers périphérie des dendritesInhibition des fibres parallèlesApprentissage moteur: Dépression à Long terme

Influx vers le corps cellulaire: pot. ComplexeInhibition des neurones du noyau SynchronisationCorrection à court terme

Mode régulation

Un cristal neuronal

Un système focal

Noyaux Cérébelleux

OliveNoyaux Tronc

Moelle

F. Grimpantes

+ -

SPECIFICITE D ’ACTIVATION

F. Moussues

+

F. Parallèle

-Pot. SimplePot.complexe

-

+

Fonction inverse approchée

Mvt voulu

(cx moteur)

Mvt effectué

(motoneurone)

Etat du corps

(Cx sensoriel)

20ms

20ms

viscoélasticité Cervelet

Fonction inverse approchée

• Traitement en continu de l’info sensori- motrice

• Intégration de la constante de temps

• Intégration de l’espace extérieur (trajectoire)

• Intégration de l’état intérieur

• Correction en continu et par anticipation de

l’ordre moteur

• Mouvement conforme au mouvement voulu

Apprentissage moteur

• Dépression à long terme

• Mémoire procédurale de gestes

complexes

DEPRESSION A LONG TERME

F. Grimpante

Glutamate

Na+

Ca++

Dendrite de Purkinje

F. Parallèle

Glutamate

Na+

Rec. AMPA

Rec. GlutamateProt. G

Prot. Kinase C

Organisation anatomique

Lobe Ant: sensori moteur

Lobe Post: cognitif

Cervelet Latéral

• Afférence 1: – cx cérébral- nyx Pont

• Efférences: – VLTh-Cx

• Rôle:– Reçoit copie du

programme

– Réalise une modulation

– Programme le mvtsuivant

• Afférence 2: – cx cérébral-olive:

apprentissage

Programmation du mouvement

Cervelet Intermédiaire

• Afférence spinale: proprioception: info sur exécution en cours

• Efférence 1: – VLTh-CxMot

• Rôle: – module voie motrice

– Ajuste paramètres cinématiques distaux

– Active agoniste PUIS antagoniste

• Efférence 2:– Réticulée: Tonus

Régulation du mvt volontaire des membres

• Afférences:

– Spinale (proprioception)

– Réticulée

• Efférences:

– Vestibulo spinal: muscles paravertébraux et

proximaux: équilibre postural

– Réticulo spinal: tonus

– Réticulo Pontin: Ny oculomot: saccades

Contrôle muscles proximaux et axiaux:

érection du rachis et maintien de la tête

Cervelet Médian

Cervelet Flocculo Nodulaire

• Afférences:

– Ny vestibulaires + CGL+ Colliculus

• Efférences:

– Ny Vestibulaire Médian + FLM: ny oculomot +

motoneurones muscles cervicaux: Poursuite

– Ny Vestibulaire lat – motoneurones ext rachis:

équilibre postural

Contrôle équilibre axial

Sémiologie Motrice

• CINETIQUE

• Spatiale:– Dysmétrie

– Asynergie

• Temporelle:– Adiadococinésie

– Dyschronométrie

• Latéral + Interméd

• Programmation + régulation

• STATIQUE

• Equilibre:– Posture

– Marche

• Tonus

• Oculomotricité– Saccades

– Poursuite

• Médian + FlocculoNod

• Tonus + équilibre

Scale for the assessment and rating of ataxia SARA – 3rd version

Sd Cérébelleux CINETIQUE

SPATIAL• DYSMETRIE:

– Talon-genou

– Doigt-nez

• Hypo ou hypermétrie

– Pronation

– Epreuve des traits

– Poursuite de cible

Poursuite de cible

• 5: Finger chase:

• Proband sits comfortably. If necessary, support of feet and trunk is allowed.

• Examiner sits in front of proband and performs 5 consecutive sudden and fast pointing movements in unpredictable directions in a frontal plane, within 50 % of proband´s reach.

• Movements have an amplitude of 30 cm and a frequency of 1 movement every 2 s.

• Proband is asked to follow the movements with his index finger, as fast and precisely as possible.

• Average performance of last 3 movements is rated.

• Slow and hypometric movement is rated 0 as long as patient is able to perform 5 pointing movements.

0 Normal,

1 Hypermetriaovershooting target<5

2 Hypermetria,< 15 cm

3 Hypermetria,> 15 cm

4 Unable to perform 5 pointing movements due to any reason

Doigt/Nez

6: Nose-finger test.

• Proband sits comfortably. If necessary, support of feet and trunk is allowed.

• Examiner sits in front of proband and performs 5 consecutive pointing movements in horizontal direction in a frontal plane, within 90 % of proband´sreach. Movements are performed at moderate speed with an amplitude of 30 cm.

• Proband is asked to point repeatedly with his index finger from his nose to examiner´s finger and back.

• Average performance of movements is rated.

• Amplitude of tremor is defined as maximal distance from the target or movement trajectory.

0 Normal, no tremor

1 Tremor with an amplitude <

2 cm

2 Tremor < 5 cm

3 Tremor > 5 cm

4 Unable to perform 5

pointing movements due

to any reason

Talon/genou

8) Heel-shin slide:

• rated separately for each side

• Proband lies on examination bed, without vision of his legs.

• Proband is asked to lift one leg, point with the heel to the opposite knee, slide down along the shin to the ankle, and to lay the leg back on the examination bed.

• The task is performed 3 times.

• Slide-down movements should

be performed within1 s.

• 0 Normal

• 1 Slight difficulties, contact to shin maintained

• 2 Clear difficulties, goes off shin up to 3 times during 3 cycles

• 3 Severely unstable, goes off shin 4 or more times during 3 cycles

• 4 Unable to perform the task

Sd Cérébelleux CINETIQUE

SPATIAL• ASYNERGIE:

– Lever du décubitus

• Décollement talons

– Accroupissement

• Sans décollement des talons

– Se pencher en arrière:

• Absence de flexion des genoux et chevilles

– Mettre le pied sur une chaise:

• décomposition du mouvement

Sd Cérébelleux CINETIQUE

TEMPOREL

• DYSCHRONOMETRIE

– Doigt-nez simultané

– Stewart-Holmes

• Retard initiation et arrêt

• ADIADOCOCINESIE

– Mouvements rapides

alternatifs (marionnettes,

battre la mesure)

– Saler avec les doigts

Adiadiococinésie

7) Fast alternating hand movements:

rated separately for each side

• Proband sits comfortably. If necessary, support of feet and trunk is allowed.

• Proband is asked to perform 10 cycles of repetitive alternation of pro- and supinations of the hand on his/her thigh as fast and as precise as possible.

• Movement is demonstrated by examiner at a speed of approx. 10 cycles within 7 s.

• Exact times for movement execution have to be taken.

0 Normal, no irregularities (performs <10s)

1 Slightly irregular (<10s)

2 Clearly irregular, single movements difficult to distinguish or relevant interruptions (performs <10s)

3 Very irregular, single movements difficult to distinguish or relevant interruptions, >10s

4 Unable to complete 10 cycles due to any reason

Sd Cérébelleux CINETIQUE

• Tremblement:

– Action

– Oscillations

– gagnant en amplitude

et parasitant le geste à

l’approche du but

– se prolongeant quand

le but est atteint

• Bretteur de Garcin

– Discontinuité du mvt

Syndrome Cérébelleux STATIQUE

• Trouble de l’équilibre– Station debout:

• Oscillations

• Danse des tendons

• Pas de Romberg

– Marche:• Polygone

• Bras balanciers

• Ataxie marche en ligne

• Mise en route hésitante

• Marche ébrieuse

• Marche talonnante

Marche

1) Gait

– Proband is asked

– (1) to walk in safe

distance from a wall

including a half-turn

(2) to walk in tandem

(both feet on one line,

no space between

heel and toes).

0: Normal, no difficulties in walking, turning or walking tandem (up to one misstep allowed)

1 Slight difficulties, only visible when walking 10

consecutive steps in tandem

2 Clearly abnormal, tandem walking >10 steps not possible

3 Considerable staggering, difficulties in half-turn, but without support

4 Marked staggering, intermittent support of the wall required

5 Severe staggering, permanent support of one stick or light support by one arm required

6 Walking > 10 m only with strong support (two special sticks or stroller or accompanying person)

7 Walking < 10 m only with strong support (two special sticks or stroller or accompanying person)

8 Unable to walk, even with accompanying person

Station debout

2: Stance

• Proband is asked to stand

• (1) in natural position,

• (2) with feet together in parallel (big toes touching each other)

• (3) in tandem (both feet on one line, no space between heel and toe).

• Proband does not wear shoes, eyes are open.

• For each condition, three trials are allowed.

• Best trial is rated.

• 0 Normal, able to stand in tandem for > 10 s

• 1 Able to stand with feet together without sway, but not in tandem for > 10s

• 2 Able to stand with feet together for > 10 s, but only with sway

• 3 Able to stand for > 10 s without support in natural position, but not with feet together

• 4 Able to stand for >10 s in natural position only with intermittent support

• 5 Able to stand >10 s in natural position only with constant support of one arm

• 6 Unable to stand for >10 s even with constant support of one arm

Dysarthrie

4) Speech disturbance

Speech is assessed during normal conversation.0 Normal

1 Suggestion of speech disturbance

2 Impaired speech, but easy to understand

3 Occasional words difficult to understand

4 Many words difficult to understand

5 Only single words understandable

6 Speech unintelligible (no speech)

Autres Troubles

• Hypotonie:

– Atteinte réticulospinale

– Cervelet médian

• ROT pendulaires

Autres échelles

• FARS: Friedreich Ataxia Rating Scale

• ICARS: International Coopérative Ataxia Rating Scale (16 items)– Mvt yeux

– Atteinte bulbaire

– Dysarthrie

– Neuropathie périphérique

– Coordination • Bretteur

• Doigt Nez

• Dysmétrie

• Adiadococinésie

• Talon/genou

• Pointage

• Stabilité posturale (pieds joints/ tandem)

• Marche (normale, tandem)

• Ecriture