What causes Upgaze palsy?
Up gaze palsy is due to damage of the vertical gaze center (rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF) and the interstitial nucleus of Cajal (INC)) and its connections.
What is an ipsilateral gaze palsy?
Neurology. Conjugate gaze palsies are neurological disorders affecting the ability to move both eyes in the same direction. These palsies can affect gaze in a horizontal, upward, or downward direction.
What is an upward gaze palsy?
The most common cause of vertical gaze palsy is damage to the top part of the brain stem (midbrain), usually by a stroke or tumor. In upward vertical gaze palsies, the pupils may be dilated. When people with this palsy look up, they have nystagmus. That is, their eye rapidly moves upward, then slowly drifts downward.
What does the abducens do?
Cranial nerve six (CN VI), also known as the abducens nerve, is one of the nerves responsible for the extraocular motor functions of the eye, along with the oculomotor nerve (CN III) and the trochlear nerve (CN IV).
What does the Pprf do?
The paramedian pontine reticular formation, also known as PPRF or paraabducens nucleus, is part of the pontine reticular formation, a brain region without clearly defined borders in the center of the pons. It is involved in the coordination of eye movements, particularly horizontal gaze and saccades.
What are the causes of vertical gaze palsies?
• Vertical gaze palsies are due to damage to pre-motor structures in the midbrain, namely the rostral interstitial nucleus of the medial longitudinal fasciculus and the interstitial nuclear of Cajal. • Vertical gaze palsies can involve upgaze, downgaze, or both.
What are the signs and symptoms of upgaze palsy?
Upgaze palsy is most common, then combined upgaze and downgaze followed by downgaze palsy. If the riMLF is affected, other signs include pupillary or ocular motor signs of third nerve palsies including wall-eyed bilateral internuclear ophthalmoplegia, impaired convergence, and skew deviation.
What is the difference between partial and complete gaze palsy?
Most vertical gaze palsies are selective in nature. In contrast, the terms “partial” or “complete” when applied to gaze palsy indicate whether some motion across midline in the paretic direction is present. Vertical palsies usually appear selective, affecting primarily saccades.
What causes cerebellar ataxia and gaze palsy?
• Several genetic defects can cause cerebellar ataxia with vertical gaze palsies, chief of which is Niemann Pick type C disease. The term “gaze palsy” is best restricted to deficits in conjugate eye movements that affect both eyes.