Eye and hand motor interactions with the Symbol Digit Modalities Test in early multiple sclerosis

Gro O Nygaard; Sigrid A de Rodez Benavent; Hanne F Harbo; Bruno Laeng; Piotr Sowa; Soheil Damangir; Kristian Bernhard Nilsen; Lars Etholm; Siren Tønnesen; Emilia Kerty; Liv Drolsum; Nils Inge Landrø; Elisabeth G Celius

doi:10.1016/j.msard.2015.08.003

Eye and hand motor interactions with the Symbol Digit Modalities Test in early multiple sclerosis

Mult Scler Relat Disord. 2015 Nov;4(6):585-9. doi: 10.1016/j.msard.2015.08.003. Epub 2015 Aug 15.

Authors

Affiliations

¹ Department of Neurology, Oslo University Hospital, Postal Box 4950 Nydalen, 0424 Oslo, Norway; Department of Clinical Medicine, University of Oslo, Postal Box 1171 Blindern, 0318 Oslo, Norway. Electronic address: g.o.nygaard@medisin.uio.no.
² Department of Clinical Medicine, University of Oslo, Postal Box 1171 Blindern, 0318 Oslo, Norway; Department of Ophthalmology, Oslo University Hospital, Postal Box 4950 Nydalen, 0424 Oslo, Norway. Electronic address: s.a.d.r.benavent@medisin.uio.no.
³ Department of Neurology, Oslo University Hospital, Postal Box 4950 Nydalen, 0424 Oslo, Norway; Department of Clinical Medicine, University of Oslo, Postal Box 1171 Blindern, 0318 Oslo, Norway. Electronic address: h.f.harbo@medisin.uio.no.
⁴ Department of Psychology, University of Oslo, Postal Box 1094 Blindern, 0317 Oslo, Norway. Electronic address: b.laeng@medisin.uio.no.
⁵ Department of Clinical Medicine, University of Oslo, Postal Box 1171 Blindern, 0318 Oslo, Norway; Department of Radiology, Oslo University Hospital, Postal Box 4950 Nydalen, 0424 Oslo, Norway. Electronic address: piotr.sowa@medisin.uio.no.
⁶ Department of Neurobiology, Karolinska Institute, SE-171 77 Stockholm, Sweden. Electronic address: soheil.damangir@ki.se.
⁷ Department of Neurology, Oslo University Hospital, Postal Box 4950 Nydalen, 0424 Oslo, Norway; Department of Neuroscience, Norwegian University of Science and Technology, 7489 Trondheim, Norway. Electronic address: kristian.b.nilsen@ntnu.no.
⁸ Department of Neurology, Oslo University Hospital, Postal Box 4950 Nydalen, 0424 Oslo, Norway. Electronic address: lareth@ous-hf.no.
⁹ Department of Clinical Medicine, University of Oslo, Postal Box 1171 Blindern, 0318 Oslo, Norway. Electronic address: siren.tonnesen@medisin.uio.no.
¹⁰ Department of Neurology, Oslo University Hospital, Postal Box 4950 Nydalen, 0424 Oslo, Norway; Department of Clinical Medicine, University of Oslo, Postal Box 1171 Blindern, 0318 Oslo, Norway. Electronic address: emilia.kerty@medisin.uio.no.
¹¹ Department of Clinical Medicine, University of Oslo, Postal Box 1171 Blindern, 0318 Oslo, Norway; Department of Ophthalmology, Oslo University Hospital, Postal Box 4950 Nydalen, 0424 Oslo, Norway. Electronic address: liv.drolsum@medisin.uio.no.
¹² Department of Psychology, University of Oslo, Postal Box 1094 Blindern, 0317 Oslo, Norway. Electronic address: n.i.landro@psykologi.uio.no.
¹³ Department of Neurology, Oslo University Hospital, Postal Box 4950 Nydalen, 0424 Oslo, Norway. Electronic address: uxelgu@ous-hf.no.

PMID: 26590666
DOI: 10.1016/j.msard.2015.08.003

Abstract

Purpose: Eye and hand motor dysfunction may be present early in the disease course of relapsing-remitting multiple sclerosis (RRMS), and can affect the results on visual and written cognitive tests. We aimed to test for differences in saccadic initiation time (SI time) between RRMS patients and healthy controls, and whether SI time and hand motor speed interacted with the written version of the Symbol Digit Modalities Test (wSDMT).

Methods: Patients with RRMS (N = 44, age 35.1 ± 7.3 years), time since diagnosis < 3 years and matched controls (N = 41, age 33.2 ± 6.8 years) were examined with ophthalmological, neurological and neuropsychological tests, as well as structural MRI (white matter lesion load (WMLL) and brainstem lesions), visual evoked potentials (VEP) and eye-tracker examinations of saccades.

Results: SI time was longer in RRMS than controls (p < 0.05). SI time was not related to the Paced Auditory Serial Addition Test (PASAT), WMLL or to the presence of brainstem lesions. 9 hole peg test (9HP) correlated significantly with WMLL (r = 0.58, p < 0.01). Both SI time and 9HP correlated negatively with the results of wSDMT (r = -0.32, p < 0.05, r = -0.47, p < 0.01), but none correlated with the results of PASAT.

Conclusions: RRMS patients have an increased SI time compared to controls. Cognitive tests results, exemplified by the wSDMT, may be confounded by eye and hand motor function.

Keywords: Cognition; Eye; Hand function; Multiple sclerosis; Multiple sclerosis functional composite; Saccades; Symbol Digit Modalities Test; Symptom assessment.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Disability Evaluation
Evoked Potentials, Visual
Female
Hand / physiopathology*
Humans
Linear Models
Male
Motor Skills* / physiology
Multiple Sclerosis, Relapsing-Remitting / diagnosis*
Multiple Sclerosis, Relapsing-Remitting / physiopathology*
Multiple Sclerosis, Relapsing-Remitting / psychology
Multivariate Analysis
Neurologic Examination
Neuropsychological Tests
Saccades* / physiology
Severity of Illness Index
Time Factors