Background/Purpose:  Abnormalities in naming speed are an unappreciated feature of cognitive dysfunction in fibromyalgia (FMS).  Approximately 50% of FMS patients with memory problems name words at a rate that is 203 milliseconds slower than the norm.  The connection between naming speed and memory loss in FMS is unclear.  Stimulant medications like methylphenidate have been known to influence naming speed and could provide clues to the relationship between cognitive functioning and naming speed.   The purpose of this paper is to determine if faster naming speed is connected to a positive change in cognitive functioning. 

Methods: A word naming speed measure (Stroop Color and Word Test) and a measure of cognitive functioning (Mental Clutter Scale:MCS) were administered to 15 patients with FMS, before receiving methylphenidate  and post methylphenidate.  The FMS patients were female, met 2010 ACR criteria for FMS and had memory problems. Methylphenidate dosage was clinically determined and ranged from 10 to 30 mg.  The median methylphenidate usage at retesting was 30 days. Naming speed was determined by the number of words named in a 45 second time period.

Results: The mean age of the FMS sample was 46.3±11.6  years  with 14.1±2.1 years of education.  Twelve of 15 FMS patients showed a significant reduction in time needed to name words post methylphenidate.  Pre- methylphenidate, they read 77.4 words in 45 seconds or 605 milliseconds (45/77.4) per word.  Post methylphenidate, they read 93 words in 45 seconds or 498 milliseconds (45/93) per word.  This represents a 107 millisecond benefit from methylphenidate. The normative sample reads 108 words in 45 sec. or 417 msec.  per word.   Post methylphenidate changes on the Cognition and Mental Clarity subscales of the MCS are shown in Table 1.  FMS patients showed a 17 point improvement with methylphenidate on Cognition, and a 19 point improvement on mental clarity.   Both  changes were significant at p<0.01.   

 Conclusion: Methylphenidate appears to have short term benefits for naming speed and cognitive functioning in fibromyalgia.  It quickly allows patients with FMS to operate at a more normal pace in naming words  and broadly improves cognitive functioning.  Elimination of the 107 millisecond time lag is thought to reset the neural clock in FMS so that word information is back in sync with other streams of neural information. The benefits of  methylphenidate clearly show  a connection between faster naming speed and improved cognition, however, it remains to  be determined  whether  positive  changes in cognition  are  brought on by  faster  neural transmission that likely underlies faster naming speed.    

  Table 1.   Pre- methylphenidate and Post- methylphenidate Scores on the Cognition and Mental Clarity Subscales of the Mental Clutter Scale.

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                            Pre- methylphenidate                     Post- methylphenidate      

 Cognition                 52.8±15.6                                          35.1±11.3**^a

 Mental  Clarity          48.1 ± 16.5                                        29.2±13.6**

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**p<0.01

^aLower scores represent improved performance

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/resetting-the-naming-speed-clock-with-methylphenidate-ritalin/