The Schedule for the Assessment of Drug-Induced Movement Disorders (SADIMoD): inter-rater reliability and construct validity

The Schedule for the Assessment of DrugInduced Movement Disorders (SADIMoD) : inter-rater reliability and construct validity A RT I C LE International Journal of Neuropsychopharmacology (2001), 4, 347–360. Copyright # 2001 CINP DOI : 10.1017\S1461145701002589 Anton J. M. Loonen1, Cees H. Doorschot2, Dianne A. van Hemert3, Marc C. J. M. Oostelbos4, Arnold E. S. Sijben5 and the MASEAS Team* Abstract The Schedule for the Assessment of Drug-Induced Movement Disorders (SADIMoD) is a newly developed instrument, consisting of a compilation of rating scales, to measure the severity of drug-induced movement disorders : dystonia, dyskinesia, Parkinsonism, akathisia, ataxia, and several types of tremors. The inter-rater reliability and the construct validity of this scale were investigated. Six investigator teams were trained by means of a standard package of instruction material to such an extent that a single member of the team could represent the entire team. Thirty-one patients [20 male\11 female ; 57n1p6n5 yr (meanp..)] with a variety of movement disorders were recorded on videotape according to the SADIMoD Schedule. Single representatives of all six teams scored these video recordings. To this set the existing SADIMoD ratings of 82 patients were added to form the so-called ‘ total data set ’. These patients were examined by 6 different researchers, who rated 4, 8, 10, 14, 18 and 28 patients, respectively, mostly in the context of a research protocol. A specific subset consisted of 12 patients that were examined three times with a two-weekly interval without any change of their medical condition or treatment. The 6 ratings of the 31 individual patients correlated to a highly significant degree, with Kendall’s Coefficients of Concordance of 0n436 to 0n891 (median 0n717). The same was true for the 6 ratings of the 7 SADIMoD subscales (median 0n578, range 0n462–0n715) Considering the total data set, the homogeneity of the various subscales was good (Cronbach’s α l 0n81–0n94, median : 0n87). The SADIMoD dyskinesia and dystonia subscales showed a highly significant mutual correlation. The Parkinsonism subscale correlated highly significantly with the rest and postural tremor subscales and to a lesser extent with the akathisia and ataxia subscales. An analysis of variance showed that the three ratings in the subset of 12 patients were not significantly different for any scale. Also Scheffe! tests for homogenous subsets did not reveal any significant differences. When investigated under ‘ real world ’ circumstances, the inter-rater reliability of the SADIMoD was found to be satisfying. The instruction material, that was developed and used in this study, fully comes up to the requirements. The construct validity of the SADIMoD is more than sufficient. Received 21 December 2000 ; Reviewed 20 March 2000 ; Revised 30 April 2001 ; Accepted 6 May 2001 Key words : Ataxia, basal ganglia diseases, movement disorders – drug-induced, rating scales. Address for correspondence : Dr A. J. M. Loonen, Delta Psychiatric Hospital, PO Box 800, NL-3170 DZ Poortugaal, The Netherlands. Tel. : j31 10 503 13 13 Fax : j31 10 503 13 88 E-mail: Anton.Loonen!wxs.nl * The MASEAS Team consists of the examiners and\or raters and the camera-operators making the video-recordings of the six participating centres. Delta Psychiatric Hospital, Poortugaal : B. Resida, rater ; M. Kwakkelstein, rater ; C. Sterrenburg, rater ; L. Timmerman, investigator ; Th. van Zonneveld, rater ; R. Keulemans, assistant. GGZ ’s-Hertogenbosch OP ; ’s-Hertogenbosch : E. Delescen, investigator ; J. van der Veer, rater ; W. Garenfeld, rater ; G. Ackermans, assistant. GGZ ’s-Hertogenbosch VP, Vught : C. Doorschot, investigator ; W. van Rooij, rater ; Ch. Maton, rater ; H. Kaethoven, rater\assistant. GGZ Midden-Brabant, Tilburg : W. Standaert, investigator ; M. Pepping, assistant. GGZ Oost-Brabant, Rosmalen : B. Jogems, investigator ; F. Schenkelaars, rater ; M. van Gool, rater\assistant ; J. Sturkenboom, rater\assistant. PCA Zuid/Nieuw-West, Amsterdam : L. Perquin, investigator ; R. Halkema, rater ; J. Wesselius, rater ; K. Hanekroot, rater ; E. Beyaert, rater ; P. Kempe, assistant. " Delta Psychiatric Hospital, PO Box 800, NL-3170 DZ Poortugaal, The Netherlands # GGZ ’s-Hertogenbosch, PO Box 10n150, NL-5260 GB Vught, The Netherlands $ Tilburg University, Department of Psychology, PO Box 90n153, NL-5000 LE, Tilburg, The Netherlands % Two Way bv, Muntelbolwerk 1, NL-5213 SZ ’s-Hertogenbosch, The Netherlands & ABC\Opes bv, Zutphensestraatweg 17, NL-6881 WN Velp, The Netherlands 348 A. J. M. Loonen et al. Introduction The SADIMoD is a newly developed instrument to measure the severity of a variety of syndromes (Doorschot et al., 1993, 1994 ; Loonen et al., 1993, 2000). It is intended to be used in clinical trials on psychotropic drugs, in trials on the therapy of drug-induced movement disorders and in daily practice to examine the long-term course of movement disorders in individual patients. Several types of instruments have been examined for their suitability to assess drug-induced movement disorders in clinical trials (de Leon and Simpson, 1992 ; Gardos et al., 1977 ; Loonen et al., 1997). These instruments can be broadly divided into instrumentational techniques, freTable 1. Examples of rating scales to assess movement disorders Akathisia Barnes Rating Scale for Drug-Induced Akathisia (Barnes, 1989) Hillside Akathisia Scale (Fleischhacker et al., 1989) Prince Henry Hospital Akathisia Rating Scale (Sachdev, 1994) Dyskinesia Abnormal Involuntary Movement Scale (Guy, 1976) Dyskinesia Identification System Condensed User Scale (Kalachnik and Sprague, 1993) Dyskinesia Check List (Crane et al., 1969) Tardive Dyskinesia Rating Scale of Escobar (Reda et al., 1975) Tardive Dyskinesia Rating Scale of Simpson et al. (1979) Abbreviated Dyskinesia Rating Scale of Simpson et al. (1979) Dystonia Fahn–Marsden Dystonia Movement Scale (Burke et al., 1985) Parkinsonisma Echelle pour Bilan Extra-Pyramidal (Bordeleau et al., 1967). Scale for the Clinical Assessment of Parkinsonism (Mindham, 1976). Parkinson’s Disease Rating Scale of Webster (1968). Simpson-Angus Rating Scale for Extrapyramidal Side Effects (Simpson and Angus, 1970). Short Parkinson’s Evaluation Scale (Rabey et al., 1997). Targeting Abnormal Kinetic Effects (Doller Wojcik et al., 1980). Unified Parkinson’s Disease Rating Scale (Fahn et al., 1987). Multiple disorders Dokumentationssystem von Degkwitz, Heinrich und Hippius (Hippius and Logemann, 1970). Proforma for recording clinical data on motor disorders (Hershon et al., 1972 ; Kennedy et al., 1971). Extrapyramidal Symptom Rating Scale (Klett and Caffey, 1972). Rating Scale for Reversible Extrapyramidal Symptoms (Chien et al., 1974). Extrapyramidal Symptom Rating Scale (Chouinard et al., 1984). Involuntary Movement and Extrapyramidal Side-Effects Scale of May and Van Putten (Marder et al., 1984). Smith-TRIMS Tardive Dyskinesia (...truncated)