Dynamics of saccade parameters in multiple sclerosis patients with fatigue

Abstract

Fatigue is one of the most frequent and disabling symptoms in multiple sclerosis (MS). Its pathophysiology remains poorly understood and objective measures to quantify fatigue are unavailable to date. To investigate whether analysis of ocular motor movements can provide diagnostic information in MS patients with fatigue, 37 MS patients (21 female, age 44 ± 9 years) and 20 age- and gender-matched healthy controls were prospectively recruited. Fatigue was assessed with the fatigue severity scale (FSS). Twenty-five MS patients were fatigued (defined as FSS ≥ 4) and 12 MS patients were not. Subjects performed a saccadic fatigue task that required execution of uniform saccades over a period of 10 min. Saccadic amplitude, latency and peak velocities during the task were analysed and selected parameters were tested in a receiver operating characteristic (ROC) analysis. Fatigued patients showed a significantly larger decrease of saccadic peak velocity and amplitude when compared to patients without fatigue and healthy controls. Furthermore, fatigued patients showed significantly longer latencies compared to non-fatigued patients and healthy controls. Peak velocity change over time and latencies correlated with FSS scores. The best parameter to discriminate between fatigued and non-fatigued patients was peak velocity change over time (ROC; area under the curve = 0.857). Assessment of peak velocity, amplitude and latency in a saccade fatigue task is a promising approach for quantifying fatigue in MS patients.

Effects of Deep Repetitive Transcranial Magnetic Stimulation on Brain-Derived Neurotrophic Factor Serum Concentration in Healthy Volunteers

“…Furthermore, the reduction in serum BDNF is correlated with a decrease in reaction time in the alertness subtest, which could be interpreted as a direct positive effect on volunteers' attention. This finding suggests that deep high-frequency rTMS may be an effective treatment in pathological conditions such as multiple sclerosis, which are characterized by depressive mood, reduced alertness or fatigue [52,53,54,55,56,57]. To clarify the effects of high-frequency rTMS on mood and fatigability and their relationship to BDNF serum levels in a mid- or long-term setting, further clinical studies are required.…”

Pathology and MRI: exploring cognitive impairment in MS

“…19 Although the literature on the association between cognitive dysfunction and fatigue is conflicting, the high prevalence of both (up to 90% of MS patients reporting fatigue [23][24][25][26] ) will result in concomitant occurrence of both fatigue and cognitive impairment in a substantial proportion of patients which does not necessarily imply causality. However, numerous researchers have reported a relation of characteristically impaired cognitive domains such as information processing speed and alertness with fatigue.…”

The Neuro-Ophthalmology of Multiple Sclerosis

“…The authors compared conjugacy of horizontal saccades in nine MS patients with INO with eight controls during minute 1 and minute 10 of a fatigue test; they observed significant fatigue-induced worsening of conjugacy in cases of mild INO, which they postulate may reflect deteriorated fidelity of saccadic pulse transmission along demyelinated MLF. Another recent study assessed whether evaluation of oculomotor movements (saccadic amplitude, latency and peak velocities) could provide diagnostic information about fatigue in patients with MS [188]. In this study, 37 MS patients and 20 age-and gender-matched controls were assessed with the fatigue severity scale and then subjected to a saccadic fatigue task.…”