The simplest one is the caloric reflex test, in which one ear canal is irrigated with warm or cold water or air. The temperature gradient provokes the stimulation of the horizontal semicircular canal and the consequent nystagmus. Nystagmus is often very commonly present with Chiari malformation. The resulting movement of the eyes may be recorded and quantified by a special device called an electronystagmograph (ENG), a form of electrooculography (an electrical method of measuring eye movements using external electrodes), or an even less invasive device called a videonystagmograph (VNG), a form of video-oculography (VOG) (a video-based method of measuring eye movements using external small cameras built into head masks), administered by an audiologist. Special swinging chairs with electrical controls can be used to induce rotatory nystagmus.Over the past forty years, objective eye-movement-recording techniques have been applied to the study of nystagmus, and the results have led to greater accuracy of measurement and understanding of the condition. Orthoptists may also use an optokinetic drum, or electrooculography or Frenzel goggles to assess a patients eye movements. Nystagmus can be caused by subsequent foveation of moving objects, pathology, sustained rotation or substance use.
Lichen spinulosus  is a rare skin disorder characterized by follicular keratotic papules that are grouped into large patches. It is a variant of keratosis pilaris named for its resemblance to a patch of lichen. See also
Hook nail
List of cutaneous conditions

Notes
References
Friedman S (1990). "Lichen spinulosus. Clinicopathologic review of thirty-five cases". J Am Acad Dermatol. 22 (2 Pt 1): 261–4. doi:10.1016/0190-9622(90)70035-G. PMID 2179296. External links
Derm Net NZ
Emedicine
Thehinhso