Disruption of smooth pursuit eye movements in cirrhosis: Relationship to hepatic encephalopathy and its treatment

Abstract

Smooth pursuit eye movements (SPEM) are the conjugate movements used to track the smooth trajectory of small dots. Jerky or 'saccadic' ocular pursuit has been reported in patients with cirrhosis, but no formal assessment of SPEM has ever been undertaken. The aim of this study was to evaluate SPEM in patients with cirrhosis and varying degrees of hepatic encephalopathy. The patient population comprised 56 individuals (31 men, 25 women) of mean age 51.1 (range, 25-70) years, with biopsy-proven cirrhosis, classified, using clinical, electroencephalographic, and psychometric variables, as either neuropsychiatrically unimpaired or as having minimal or overt hepatic encephalopathy; patients were further categorized in relation to their treatment status. The reference population comprised 28 healthy volunteers (12 men, 16 women) of mean age 47.3 (range, 26-65) years. SPEM was assessed using an electro-oculographic technique. Visual inspection of the SPEM recordings showed clear disruption of smooth pursuit in the patients with minimal hepatic encephalopathy, and more pronounced disruption, if not complete loss, of smooth pursuit in patients with overt hepatic encephalopathy. The differences observed in quantifiable SPEM indices between the healthy volunteers/unimpaired patients and those with overt hepatic encephalopathy were significant (P < .05). In conclusion, SPEM performance is impaired in patients with hepatic encephalopathy in parallel with the degree of neuropsychiatric disturbance: the pathophysiology of these changes is unknown, but retinal, extrapyramidal, and attentional abnormalities are likely to play a role. Treatment status confounds the classification of neuropsychiatric status and should be taken into account when categorizing these patients. (HEPATOLOGY 2005;42:772-781.)

Review article: the design of clinical trials in hepatic encephalopathy - an International Society for Hepatic Encephalopathy and Nitrogen Metabolism (ISHEN) consensus statement

“…It was agreed that patients with a history of overt HE or treatment exposure should be excluded from these trials as treatment status has a significant confounding effect on the classification of neuropsychiatric performance. 34 Patients with overt HE may show few, if any, clinical abnormalities following treatment but retain some degree of neuropsychometric or neurophysiological impairment in the longer term. 3,35,36 These patients may be classified as having minimal HE but their responses to treatment will differ substantially from those diagnosed as having minimal HE de novo.…”

Using saccades to diagnose covert hepatic encephalopathy

“…Finally, previous studies have demonstrated that HE affects eye movements. Smooth pursuit eye movements are disrupted in conjunction with the degree of encephalopathy (Montagnese 2005), and a recent pilot study using saccadometry has shown increased saccadic latency in HE, correlating both with psychometric tests and flicker fusion performance (Krismer et al 2010). We therefore investigated whether the measurement of saccades might provide a novel quantitative neurological assessment for the diagnosis of CHE.…”

Saccadic latency in hepatic encephalopathy: a pilot study

“…Somooth pursuit eye movements have been more recently shown to correlate with the degree of neurologic impariment, but their use is limited by the need for specialized equipment and head fixation (Montagnese et al 2005). …”