Penn Spasm Frequency Scale (PSFS)

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Tool Description

  • 2 component self-report measure of the frequency of reported muscle spasms which is commonly used to quantify spasticity.
  • Developed to augment clinical ratings of spasticity and provide a more comprehensive understanding of an individual’s spasticity status.
  • The first component is a 5 point scale assessing the frequency with which spasms occur ranging from “0 = No spasms” to “4 = Spontaneous spasms occurring more than ten times per hour”. The second component is a 3 point scale assessing the severity of spasms ranging from “1 = Mild” to “3 = Severe”. The second component is not answered if the person indicates they have no spasms in part 1.

ICF Domain:

Body Function – Subcategory: Neuromusculoskeletal & Movement-related Functions and Structures

Number of Items:


Brief Instructions for Administration & Scoring


  • Self-report
  • Patients report their perceptions of spasticity with regards to frequency and severity.


Scoring: N/A


MCID: not established in SCI
SEM: not established in SCI
MDC: not established in SCI

  • The specific grades are simple to interpret although no standardization of time frame is specified for test administration (i.e. within the last hour, day, week, etc.) and specific grades for spasm severity may mean different things to different people.
  • No normative data have been reported so far for the SCI population
  • Published data for the SCI population is available for comparison (see the Interpretability section of the Study Details sheet).



Training Required:

No training is required; however, understanding spasticity likely improves the scale’s utility.


See the article 'Penn et al. 1989' for details.

Clinical Considerations

  • The scale is subject to concomitant subclinical conditions such as fullness of the bladder, development of a symptomatic urinary tract infection, anxiety level, room temperature, subject comfort, and many other conditions.
  • In general, self-report measures of spasticity correlate only moderately with clinical examination suggesting that the elements of spasticity evaluated in the physical examination do not represent what is important to persons with SCI spasticity. To more fully understand spasticity as experienced by the client, self-report spasticity measures are an important adjunct to other clinical measures of spasticity.
  • The PSFS is easy to understand, presents minimal patient burden (easy to administer during routine clinical visits).

Measurement Property Summary

# of studies reporting psychometric properties: 6


  • Intra-rater reliability is Moderate to High for the PSFS part 1, spasm frequency (alpha=0.883-0.935) and for the PSFS part 2, spasm frequency-severity combination (alpha=0.729-0.812)
  • Inter-rater reliability is High within a 3 day time interval (alpha=0.857-0.862)

[Mills et al. 2018]


  • Correlation of the PSFS is Moderate with the Ashworth tested on the hip (r=0.43), knee (r=0.43) and ankle (r=0.51), and the SCATS tested on the clonus (r=0.59), flexor (r=0.41) and extensor (r=0.40).

[Benz et al. 2005, Priebe et al. 1996]


  • After administration of IT Baclofen, Ashworth was reduced from 4±1 to 1.2±0.4 (P=.0001) with a concomitant decrease in spasm frequency of 3.3±1.2 to 0.4±0.8 (P<.0005).
  • After mean follow-up of 19.2 months, Ashworth was 1.0± 0.1 and PSFS was 0.3± 0.6.

[Penn et al. 1989, Gianino et al. 1998, Aydin et al. 2005, Boviatsis et al. 2005]

Floor/ceiling effect:

No values were reported for the presence of floor/ceiling effects in the PSFS for the SCI


Dr. Vanessa Noonan, Kyle Diab, Matthew Querée, Risa Fox

Date Last Updated:

August 24, 2020

Download the measure

Download Worksheet:
See the article 'Penn et al. 1989' for details.





Equipment Needed


Adams MM, Ginis KA, Hicks AL. The spinal cord injury spasticity evaluation tool: development and evaluation. Arch Phys Med Rehabil. 2007;88(9):1185-92.

Aydin G, Tomruk S, Keles I, Demir SO, Orkun S. Transcutaneous electrical nerve stimulation versus baclofen in spasticity: clinical and electrophysiologic comparison. Am J Phys Med Rehabil 2005;84:584-592.

Benz EN, Hornby TG, Bode RK, Scheidt RA, Schmit BD. A physiologically based clinical measure for spastic reflexes in spinal cord injury. Arch Phys Med Rehabil 2005;86:52-59.

Boviatsis EJ, Kouyialis AT, Korfias S, Sakas DE. Functional outcome of intrathecal baclofen administration for severe spasticity. Clin Neurol Neurosurg 2005;107:289-295.

Gianino JM, York MM, Paice JA, Shott S. Quality of life: effect of reduced spasticity from intrathecal baclofen. J Neurosci Nurs 1998;30:47-54.

Penn RD, Savoy SM, Corcos D, Latash M, Gottlieb G, Parke B, Kroin JS. Intrathecal baclofen for severe spinal spasticity. New England Journal of Medicine, 1989; 320(23): 1517-1521.

Priebe MM, Sherwood AM, Thornby JI, Kharas NF, Markowski J. Clinical assessment of spasticity in spinal cord injury: a multidimensional problem. Arch Phys Med Rehabil 1996; 77:713-716.