The aim of this study is to determine the word frequency for all thirty letters of the Croatian alphabet and to collect normative data for the letter fluency task in Croatian speakers. Ninety two healthy participants were given each of the Croatian letters, and asked to generate as many words as possible in 60 seconds for each letter. Results suggested that participants generated most frequently words starting with the letters as follows: »K«, »P«, »S« and »M«

Folnegović Šmalc, Vera

Harrison, John E.

Joka, Svetislav

Kalinić, Dubravka

Mimica, Ninoslav

Žakić Milas, Danijela

English

University of Zagreb Medical School Repository

Coll. Antropol. 35 (2011) Suppl. 1: 235–238Short communicationA Validation Study of Appropriate PhonologicalVerbal Fluency Stimulus Letters for Use withCroatian Speaking IndividualsNinoslav Mimica1,2, Danijela @aki} Milas1, Svetislav Joka1, Dubravka Kalini}1,2,Vera Folnegovi} [malc1,2 and John E Harrison3,41 University of Zagreb, Vrap~e University Psychiatric Hospital, Department of Psychiatry, Zagreb, Croatia2 University of Zagreb, School of Medicine, Zagreb, Croatia3 CogState Ltd., Warminster, United Kingdom4 Imperial College, Division of Neurosciences & Mental Health, London, United KingdomA B S T R A C TThe aim of this study is to determine the word frequency for all thirty letters of the Croatian alphabet and to collectnormative data for the letter fluency task in Croatian speakers. Ninety two healthy participants were given each of theCroatian letters, and asked to generate as many words as possible in 60 seconds for each letter. Results suggested thatparticipants generated most frequently words starting with the letters as follows: »K«, »P«, »S« and »M«.Key words: verbal fluency, healthy participants, Croatian, clinical neuropsychology, test, COWAT, cognitiveIntroductionAlmost any test format that provides the opportunityfor unrestricted speech will test verbal fluency. Fluencyof speech (»verbal fluency«) is typically measured by thequantity of words produced usually to a stimulus orwithin a restricted category, and within a specific timelimit. Fluency tests with the task of generating words ac-cording to an initial letter require subjects to seek appro-priate strategy for guiding their search for words. Thesetasks are most difficult for subjects who cannot developstrategies of their own1. Examples of effective strategiesinvolve use of words with the same initial consonant,variations on a word, or variations on a theme1. Categoryfluency tests, calling for items in a category, providestructure, and, from that point of view are not as de-manding. However, in spite of existence of different welldefined categories, subjects with good searching strate-gies will often develop subcategories for organizing theirrecall. Frequently, verbal fluency is measured by word--naming test originated by Stanford-Binet. An alterna-tive method for measuring verbal fluency is to employthe Controlled Oral Word Association Test (COWAT).The COWAT is widely used in clinical neuropsychology,primarily as a measure of verbal fluency, but also as ameasure of executive skills such as working memory,planning and strategy. COWAT has also been widely usedas a measure of verbal fluency and executive skills in anumber of clinical drug trials, including studies of an am-yloid lowering treatment for use in patients with Alzhei-mer’s disease2, and in the EXPRESS trial of rivastigminein patients with Parkinson’s disease3. Variations of theCOWAT are also included in the various neuropsycho-logical batteries like NCCEA4, or Multilingual Aphasiaexamination5. The purpose of the test is to evaluate thespontaneous production of words beginning with a givenletter or of a given class under restricted search condi-tions, i.e. a given letter of the alphabet, and within a lim-ited amount of time6. Many authors pointed out that suc-cessful performance on these tests depends in part on thesubject’s ability to organize output of information interms of clusters of meaningfully related words7. Verbalfluency performance is also known to be correlated withword knowledge, auditory attention and long-term ver-bal memory8–10. Participants must be able to develop astrategy for retrieving words from memory as well askeeping track of what words have already been said in aworking memory system Generally, optimal fluency per-235Received for publication October 16, 2009formance involves generating words within a subcate-gory and, when a subcategory is exhausted, switching toa new subcategory. These behavioural components wereidentified11 and than operationalised as »clustering« and»switching«12,13. Clustering is the ability to producewordswithin phonetic and semantic subcategories, and switch-ing isthe ability to shift between clusters. Research hasdetermined that clustering and switching are both corre-lated with the number of words generated in semanticfluency tasks. However, switching is better correlatedwith the number of words generated on phonemic flu-ency.. Clustering is related to temporal lobe functioningas indicated by impaired performance among patientswith temporal lobectomy14. Switching is related to fron-tal functioning, and it is specifically impaired among pa-tients with left dorsolateral and superior medial fron-tal-lobe lesions15. Many patients experience changes in»speed« and »ease« of verbal production. Impaired verbalproduction in »speed« (e.g. speed of verbal retrieval orspeed of formulating effective recall strategies) and »ease«,is according to previous coincidence with term »switch-ing«, associated with frontal lobe damage, particularlythe left frontal lobe anterior to Broca’s area16,17. A reduc-tion in word fluency has also been reported with diffuse,multifocal and non-frontal lobe damage8. Switching isalso decreased under conditions of divided attention12.Reduced capacity to generate words has also been associ-ated with Alzheimer’s- type dementia15,18–20. Age, sex,and education have also been found to influence perfor-mance21–25 and so the performance of individuals withless than a high school education must be interpretedwith caution. With regard sex differences, it seems thatthe performance of females is better preserved after age55. As many authors suggested, word fluency tests pro-vide an excellent measures from which we can find outhow the subject organized his thinking strategies.Controlled Oral Word Association Test5,21 first calledVerbal Associative Fluency test consists of three word--naming trials. The set of letters that were first em-ployed, »F«, »A«, »S«, has been used so extensively, thatthis test is sometimes called »FAS«. The 1976 version pro-vides norms for two sets of letters, »CFL« and »PRW«1,26.This affects the results to some extent because of differ-ences in vocabulary size for each letter27. These letterswere selected on the basis of the frequency of Englishwords beginning with these letters. In the »FAS« set, »F«has the lowest while »S« has the highest dictionary fre-quency. Overall, it seems that »FAS« version allows morevocabulary choices than »CFL« or »PRW« versions, butthe last two sets are approximately equivalent in theamount of choices offered. Keeping with the goal of de-veloping a multilingual battery for the examination ofaphasia, Benton and Hamsher (1976), give the frequencyrank for letters in French, German, Italian and Spanish.Although the COWAT is increasingly employed in inter-national trials, very little is known about the utility ofthe English version of the test in non-English speakingpopulations28. English versions of the test employ letterstimuli for which native English speakers are most flu-ent, and these letters may be inappropriate for use withCroatian speakers29,30. Many investigators also note highimportance of adequate interpretation of these tests3.They point out that lack of normative data makes judg-ments regarding impairment in individual study partici-pants very difficult. Remedying this lack of informationis thus of key importance if we are to employ verbal flu-ency tasks as a routine measure of verbal memory, atten-tion, and the ability to initiate systematic search andretrieval31.AimThe aim of the study was to find out the word fre-quency for all thirty letters of the Croatian alphabet inorder to identify the most appropriate letters for usewith Croatian speaking study participants. This method-ology replicates the investigation originally conductedwith English speakers and by which the most appropri-ate letters were selected for use. We also sought to deter-mine whether there are any differences between Cro-atian and English speakers with respect to fluency.Subjects and MethodsThere were 92 healthy participants, without a historyof neurological disorder, learning disability or psychiatricconditions requiring medication, age ranged from 18 to52 years. For two participants we omitted informationabout their gender and for one participant about his age.Thus, a total of 92 persons were screened, resulting in afinal sample of 90 individuals. Among 90 participantsthere were 68 females (75.6%) and 22 males (24.4%). Ofthe total group, 73 were between the ages of 18–30, 9were between the ages of 31–41, and 9 were between theages of 42–52. Thus the majority of the participants werebetween 18–30 years of age. Two participants have re-ceived 8 years of education, fifteen had completed be-tween 9 and 12 years of education, and 72 had earnedabove of 13 years of education. For three participants noinformation about their education level was available.Administration and ScoringStandard instructions were employed in the adminis-tration of the test6 with some exceptions – participantswill try to produce as many words longer than three let-ters as they can for all thirty letters of Croatian alphabet.All participants will be given the initial letters in whichthe subject had to generate the words in alphabetic order.Instruction for test is as follows: »I will say you a letter ofthe alphabet. Then I want you to give me as many wordsas you can that begin with that letter as quickly as youcan. For instance, if I say »B« you might give me »bad,battle, bed... «. I do not want you to use words which areproper names such as »Boston, Bosna, Branimir«. Also,do not use the same word again with a different endingsuch as »jelo« and »jesti«. So, you can’t use verbs in yourverbal production. »Any questions? Begin when I say theN. Mimica et al.: Appropriate Phonological Verbal Fluency Stimulus Letters, Coll. Antropol. 35 (2011) Suppl. 1: 235–238236letter. The first letter is A. Go ahead«. We begin timingimmediately, and allow 1 minute for each letter. After 1minute, the experimenter says: »Fine« or »Good«. If theparticipants discontinue before the end of the one min-ute, we encourage them to try to think of more words. Ifthere is a silence of more than 15 seconds, we repeat thebasic instruction, and the letter. For scoring purposes, wewrite down the actual words in the order in which theyare produced. If there are some words with possible alter-native meaning, at the end of the one minute period, weask the participant what was meant by this word. Theadministration takes little bit more than 30 minutes.The scores are the sum of all admissible words for the let-ters of Croatian alphabet. Slang terms and foreign wordsthat are part of standard Croatian are acceptable. Inad-missible words produced under these instructions arenot counted as correct (i.e. verbs, variations, repetitions).Errors are useful in that they can provide clues to certaintypes of disorders – e.g. repetitions (possible persevera-tions), paraphrasias, spelling errors. Often the order ofwords produced suggests clues to search strategy of theparticipant.Results and DiscussionThe average number of generated words beginningwith certain letter ranged from a low of 2.45 for »]« to12.96 for »K«. Participants generated the greatest amountof words beginning with the letters »K« (M-12.96), »P«(M-11.87), »S« (M-11.50) and »M« (M-11.30). Due to therather small and unrepresentative sample, these are pro-visional results that do not permit robust estimates ofnorms and calculation of percentiles. Nevertheless, wehave no reason to believe that the ranking of the lettersobtained in the study is any different in the Croatianpopulation or in any clinical group. Further research is,however, needed in order to provide and establish moreprecise estimations of population parameters of means,variances and percentile values.ConclusionOur results suggest that there are differences amongmost frequent letters in COWAT between Croatian andEnglish speakers. We recommend the use of the letters»K«, »P«, »S« and »M« in studies of verbal fluency(COWAT) performance conducted with Croatian speak-ing individuals.R E F E R E N C E S1. HARRISON J, MINASSIAN SL, JENKINS L, BLACK RS, KOL-LER M, GRUNDMANM, Arch Neurol, 64 (2007) 1323. — 2. HARRISONJE, BUXTON P, HUSAIN M, WISE R, Br J Clin Psychol, 39 (2000) 181.— 3. SPREEN O, BENTON AL, Neurosensory Center Comprehensive Ex-amination for Aphasia (NCCEA) (University of Victoria NeuropsychologyLaboratory, Victoria, 1977). — 4. BENTON AL, HAMSHER KdeS, Multi-lingual Aphasia Examination, Manual revised (University of Iowa, IowaCity, 1978). — 5. SPREEN O, STRAUSS E, A compendium of neuropsy-chological tests, Second edition, (Oxford University Press, New York/Ox-ford, 1998). — 6. ESTESWK, Am Psychol, 29 (1974) 740. — 7. RUFF RM,LIGHT RH, PARKER SB, LEVIN HS, Brain Lang, 57 (1977) 394. — 8.CROWE SF, J Clin Exp Neuropsychol, 20 (1998) 391. — 9. BITTNER RM,CROWE SF, Brain Inj, 20 (2006) 971. — 10. GRUENEWALD PJ, LOCK-HEAD GR, J Exp Psychol Hum Learn, 6 (1980) 225. — 11. TROYER AK,MOSCOVITCH M, WINOCUR G, Neuropsychology, 11 (1997) 136. — 12.TROYER AK, J Clin Exp Neuropsychol, 22 (2000) 370. — 13. TROYER AK,MOSCOVITCH M, WINOCUR G, ALEXANDER MP, STUSS D, Neuro-psychologia, 36 (1998) 449. — 14. TROYER AK, MOSCOVITCH M, WI-NOCUR G, LEACH L, FREEDMAN M, J Int Neuropsychol Soc, 4 (1998)137. — 15. MILNER B, Psychological aspects of focal epilepsy and its neu-rological management. In PURPURA DP, PENRY JK, WALTER RD (Eds):Advances in neurology, Vol. 8 (Raven Press, New York, 1975). — 16. 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Antropol. 35 (2011) Suppl. 1: 235–238237TABLE 1AVERAGE FREQUENCY AND OTHER STATISTICAL INDICATORSOF THE GENERATED WORDS WITH THE SAME INITIALLETTER ON CROATIAN SAMPLE (N=90)Letter Minimum Maximum X SDK 4 20 12.96 3.68P 4 22 11.87 3.69S 5 22 11.50 3.70M 3 19 11.30 3.71R 3 18 10.98 3.22T 2 25 10.84 3.78V 4 20 10.72 3.32B 2 20 10.25 3.77L 2 18 9.84 3.20G 2 20 9.47 3.82Z 3 20 9.28 3.08[ 3 19 8.80 3.17O 3 16 8.49 2.97D 0 17 8.46 3.65@ 4 17 8.30 2.71N 1 18 8.16 3.15A 1 16 7.85 3.14J 1 16 7.75 3.16U 2 18 7.66 3.12F 3 16 7.55 2.71^ 1 13 7.42 2.91C 0 15 6.70 2.81H 1 13 6.54 2.51I 1 15 6.13 2.74E 0 14 5.51 2.76LJ 1 15 5.01 1.94D@ 0 10 3.59 1.76NJ 0 7 2.87 1.60\ 0 7 2.49 1.61] 0 6 2.45 1.42butions to neuropsychological assessment (Oxford University Press, NewYork,1983). — 21. TOMBAUGH TN, KOZAK J, REES L, Arch Clin Neuro-psychol, 14 (1999) 167. — 22. TOMER R, LEVIN BE, Percept Mot Skills,76 (1993) 465. — 23. RODRIGUEZ-ARANDA C, MARTINUSSENM, DevNeuropsychol, 30 (2006) 697. — 24. LOONSTRA AS, TARLOW AR, SEL-LERS AH, Appl Neuropsychol, 8 (2001) 161. — 25. LACY MA, GORE PA,PLISKIN NH, HENRY GK, Clin Neuropsychol, 10 (1996) 305. — 26.BORKOWSKI JG, BENTONAL, SPREENO, Neuropsychologia, 5 (1967)135. — 27. HARRISON JE, MINASSIAN SL, JENKINS L, BLACK RS,KOLLER M, GRUNDMAN M, Arch Neurol, 64 (2007) 1323. — 28. MI-MICAN, JOKA S, KALINI] D, @AKI]MILAS D, FOLNEGOVI] [MALCV, HARRISON J, Eur J Neurol, 16 (2009) 467. — 29. MIMICA N, @AKI]MILAS D, JOKA S, KALINI] D, FOLNEGOVI] [MALC V, HARRISONJE, Abstract Book of The Third Croatian Congress of Neuroscience, (2009)71. — 30.ROSNER A, HODGES J, J Neurol Neurosurg Psychiatry, 57(1994) 1389.N. MimicaUniversity of Zagreb, Vrap~e University Psychiatric Hospital, Department of Psychiatry, Bolni~ka cesta 32, 10090 Zagreb,Croatiae-mail: ninoslav.mimica@bolnica-vrapce.hrFONOLO[KA VERBALNA FLUENTNOST NA HRVATSKOM UZORKU: PRIMJENA TESTA, IZBORPODRA@AJA I NORMES A @ E T A KCilj studije jest istra`iti u~estalost rije~i za svih trideset slova hrvatske abecede, odnosno prikupiti normativne po-datke za zadatke fonolo{ke verbalne fluentnosti na hrvatskom uzorku. Na 92 zdrava ispitanika primijenili smo testverbalne fluentnosti za svako slovo hrvatske abecede i tra`e}i od njih da za svako slovo generiraju {to je mogu}e ve}ibroj rije~i unutar 60 sekundi. Rezultati pokazuju da su ispitanici generirali najve}i broj rije~i s po~etnim slovom »K«,»P«, »S« i »M«.N. Mimica et al.: Appropriate Phonological Verbal Fluency Stimulus Letters, Coll. Antropol. 35 (2011) Suppl. 1: 235–238238

A validation study of appropriate phonological verbal fluency stimulus letters for use with Croatian speaking individuals [Fonološka verbalna fluentnost na hrvatskom uzorku: primjena testa, izbor podražaja i norme]

A validation study of appropriate phonological verbal fluency stimulus letters for use with Croatian speaking individuals [Fonološka verbalna fluentnost na hrvatskom uzorku: primjena testa, izbor podražaja i norme]

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