Photo Credit: Dr_Microbe

Study determines that the way patients with MS perceive their symptoms affects how difficult they report the ability to complete functional activities.

Slowed processing speed affects the time it takes for people with multiple sclerosis (MS) to complete functional activities. It also affects how much help they need to complete them. However, the symptoms MS patients perceive affect how difficult they report those activities to be, researchers reported in the International Journal of MS Care.

Although objective cognitive functioning (processing speed) predicted completion time and level of assistance needed for these tasks, even after considering factors such as disability, participants’ perception of their MS symptoms (subjective cognitive functioning, depressive symptom severity, and fatigue) significantly contributed to their reported levels of difficulty with ADLs and IADLs, senior study author Elizabeth S. Gromisch, PhD, MSCS, and co-authors wrote.

The study team investigated how objective and subjective measures of cognition, depression, and fatigue contribute to basic activities of daily living (ADLs)—such as eating, bathing, and toileting—and to more complex instrumental ADLs (IADLs)—such as managing finances, shopping, and cooking. They analyzed data from 217 patients who participated in a larger study of upper extremity function in MS at one academic MS research center. This subgroup of participants had MS, ranged from 20 through 73 years of age, scored 22 or greater on the Mini Mental State Examination (MMSE), and spoke English.

Outcome measures of ADL and IADL abilities included the Functional Status Index-Assistance (FSI-A), the Functional Status Index-Difficulty (FSI-D), and the Test D’évaluation Des Membres Supérieurs de Personnes Âgées (TEMPA) [Assessment Test for Upper Limbs of Elderly People].

Predictors included the Symbol Digit Modalities Test (SDMT) for objective cognition, the Performance Scales-Cognition (PS-C) for subjective cognition, the Center for Epidemiologic Studies Depression Scale (CES-D-10) for depressive symptom severity, and the Modified Fatigue Impact Scale (MFIS-5) for fatigue.

Determining Cognitive Function

The study population was predominantly White (85.7%) and female (77.0%). Most participants (83.4%) had more than 12 years of education. The median score on the Patient-Determined Disease Steps was 3, indicating gait disability.

On average, participants had a z-score of -0.81±1.26 on the SDMT and a median rating of 2 on the PS-C, representing mild cognitive disability. The median score was 8.00 for the CES-D-10 and 10.00 for the MFIS-5. Median performance rankings on the TEMPA, FSI-A, and FSI-D were 127.88 seconds, 1.24 (ie, between being independent and using devices), and 1.28 (ie, between none and mild difficulty), respectively.

After the researchers controlled for demographics and analyzed correlations and hierarchical linear regressions, they found that:

• The SDMT significantly predicted the TEMPA and the FSI-A, while the PS-C predicted only the FSI-D.
• The CES-D-10 predicted the FSI-D, even after considering PS-C and SDMT; however, the MFIS-5 only predicted the FSI-D when the SDMT was included.
• Neither the CES-D-10 nor the MFIS-5 significantly predicted the FSI-A or the TEMPA.

Address Cognitive Impairment, Depression, & Fatigue

The research team was surprised by the significance of the participants’ cognitive function, Dr. Gromisch says. She advises clinicians to perform a brief cognitive assessment, such as the SDMT, for patients who report needing more time or assistance to complete everyday activities.

“If the results show slowed processing speed, the patient may benefit from a referral to cognitive remediation. Psychoeducation, such as explaining how their cognitive issues are contributing to functional issues, may also be helpful.”

Cognitive impairment, depression, and fatigue are all crucial issues for persons with MS, Dr. Gromisch notes.

“For patients who report more difficulty with their daily activities but who do not have impairments on objective cognitive testing, the clinician may consider evaluating their level of depression, fatigue, and perceptions of cognitive functioning,” she advises. “Besides clarifying whether referral is needed, the test results can inform conversations with patients about why these symptoms affect their functioning.”

Regularly assessing these concerns can provide valuable insights into patients’ functional problems, Dr. Gromisch notes.

Key Takeaways

• Scores on the Symbol Digit Modalities Test and the Performance Scales-Cognition represent mild cognitive disability.
• Cognitive assessments can identify which patients may benefit from a referral to cognitive remediation.
• For some patients, fatigue and depression may influence cognitive function, even in the absence of impairment on cognitive function tests.