Construction of freezing of gait questionnaire for patients with Parkinsonism N. Giladi a, * , H. Shabtai a , E.S. Simon a , S. Biran b , J. Tal c , A.D. Korczyn a a Movement Disorders Unit, Department of Neurology, Tel-Aviv Sourasky Medical Center, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel b TechnoStat Ltd, 14 Habanim St., Hod Hasharon, Israel c The Technion, Israel Institute of Technology, Haifa, Israel Received 30 September 1999; received in revised form 5 December 1999; accepted 17 December 1999 Abstract Background: Freezing of gait (FOG) is a common, poorly understood, parkinsonian symptom interfering with daily functioning and quality of life. Assessment of FOG is complex because of the episodic nature of this symptom, and the influence of mental and environmental factors on it. Objective: To design a self-reportable reliable questionnaire for FOG. Method: A questionnaire consisting of 16 items regarding gait and falls was administered together with the Unified Parkinson’s Disease Rating Scale (UPDRS) to 40 Parkinson’s disease (PD) patients (26 males) with a mean age of 72:3 ^ 9:3 years and mean Hoehn and Yahr (H&Y) stage at “Off” of 2:85 ^ 0:84. A principal component analysis with Varimax rotation was conducted on the results. Item analyses were performed and reliability computed for an abbreviated FOG questionnaire. Results: Based on these analyses, a short (six item) FOG questionnaire was constructed, which was found to be highly reliable (Cronbach alpha  0.94) for assessment of FOG and with moderate correlation with the activity of daily living (ADL) and motor parts of the UPDRS (0.43 and 0.40, respectively). Moderate correlation was also found with the FOG item at the ADL part of the UPDRS (alpha  0.66 for the “Off” and 0.77 for the “On” state). Conclusion: The FOG questionnaire that was constructed is highly reliable in assessing freezing of gait, unrelated to falls, in patients with PD.  2000 Elsevier Science Ltd. All rights reserved. Keywords: Parkinson’s disease; Freezing of gait; Scale; Questionnaire 1. Introduction Freezing of gait (FOG) is a prevalent and disabling symp- tom in Parkinson’s disease (PD) [1] and may be even more common in other parkinsonian syndromes [2]. Assessing FOG is difficult due to the great variability of its manifes- tations within each patient. This variability is the result of FOG being affected by numerous parameters including: severity of the disease and the motor state (“On”/“Off”), visual input, tight alleys, response to variable tricks, and relation to specific gait patterns such as gait initiation or turns, cognitive factors such as attention, anxiety and stress [3]. Seventy five percent of PD patients suffering from FOG reported that this problem is most disturbing at home or out of the neurologist’s office [4]. The poor correlation of reported FOG with observed FOG during the exam conducted in the office makes it impractical to assess this symptom observationally. Only extended periods of obser- vation, in a variety of daily activities, can provide a reliable assessment of FOG. Consequently, researchers have little choice but to rely on patients’ self-reports for quantification of FOG. To date, a number of different scales have been developed to assess FOG [5,6]. However, the adequacy of these scales in terms of reliability and validity has never been demon- strated. The Unified Parkinson’s Disease Rating Scale (UPDRS), which is the most commonly used scale for asses- sing parkinsonian severity [7], contains only two items relating to FOG. One of these, appearing in the ADL section of the scale, evaluates FOG by asking the patient, relating FOG severity to the appearance of falls. The other item assesses gait objectively on exam. Parkinsonism and Related Disorders 6 (2000) 165–170 Parkinsonism & Related Disorders 1353-8020/00/$ - see front matter  2000 Elsevier Science Ltd. All rights reserved. PII: S1353-8020(99)00062-0 www.elsevier.com/locate/parkreldis * Corresponding author. Tel.: + 972-3-697-4912; fax: + 972-3-697- 4911. E-mail address: ngiladi@tasmc.health.gov.il (N. Giladi).