E-thesis

Recent Submissions

  • Winkler, Alexander (Helsingin yliopisto, 2017)
    The next evolutionary step in medical imaging and radiation therapy is to employ novel detector technologies capable of photon counting operations. These detectors allow to acquire the spectrum of the radiation for each pixel. Currently used energy integrating detectors do not allow this. Two types of detector materials capable of photon counting operation are discussed in this work. With the result that the detector technology based on CdTe and CdZnTe is more matured than GaAs. The spectral information of photon counting detectors can be used for numerous applications and diagnostic improvements. A distinct example is presented for boron neutron capture therapy (BNCT). This therapy lacks an accurate real time method to determine the 10B concentration within the patient. Previous approaches failed because of the low signal to noise ratio of the used signal. A method has been proposed to improve this therapy by employing CdTe based photon counting detectors. These detectors allow detection of a secondary signal with a higher signal to noise ratio. Additionally, efforts to produce CdTe based photon counting detector arrays, for medical applications, are described.
  • Rajakaski, Rosa (Helsingin yliopisto, 2017)
    Aims. Early interaction skills are the base for later language development. Very low birth weight (VLBW) children are at a higher risk for developing language difficulties. Earlier studies have shown that both gaze behaviours and early gestures develop differently among VLBW children compared with children born full-term. The assessment of early gestures may provide help in finding at least some of the children who are at risk for later language difficulties. The aim of this study was to analyze the use of gaze behaviours and gestures in VLBW children at the age of one, comparing the results with a control group. We also compared gestures analyzed with the Finnish version of Communicative Development Inventories (FinCDI) to gestures analyzed from video data to examine the possible connection between these different types of assessment tools. Methods. The participants of this study consisted of 10 VLBW children and 10 full-term children (N=20). The same group was also a part of a bigger study, titled Development and functioning of very low birth weight children. In this study, gaze behaviours and gestures were analyzed from video data, divided into four different types of gaze behaviours and five different types of gestures. The possible connection between gaze behaviours and gestures in and between groups was analyzed by using Spearman`s correlation. In addition, Mann Whitney`s U-test was used to analyze the possible differencies between these groups. Spearman`s correlation was also used to examine the possible correlation among the two different assessment tools. Results and conclusions. The types of gaze behaviours and gestures used most often by children in both groups were eye contact between mother and child, deictic gestures and gestures with objects. VLBW children had less eye contact, deictic gestures and gestures with objects compared with the full-term group. A significant difference between VLBW children and the control group was found in deictic gestures. It was also found that there was a significant correlation between the two assessment tools when comparing the two groups together (N=20). The results are similar to the findings of earlier studies and indicate that VLBW children use less eye contact and early gestures compared to the control group.
  • Meriläinen, Jaana (Helsingin yliopisto, 2017)
    Developmental dyslexia is a heritable learning disorder which according to the predominant theories has its core problems in the processing of speech sounds. Auditory processing deficits have been found in dyslexics and in infants with a genetic risk for dyslexia. It has been shown that infants with a genetic risk for dyslexia have attenuated or more right-hemispheric lateralized auditory event-related potentials (ERPs) to changes in speech stimuli compared to infants with no genetic risk. It has been shown that interventions can ameliorate the reading and writing skills of dyslexics and concurrently influence their ERPs. The aim of the present study was to find out if an early musical intervention can ameliorate the auditory processing skills in infants. Altogether 58 infants with a genetic risk for dyslexia were assigned to three groups where one group listened to vocal music, second group listened to instrumental versions of the same music and the third one was a control group with no intervention. After six months of intervention, auditory ERPs of the infants were recorded while the infants were presented with a repetitive pseudoword /tata/ with random infrequent duration, frequency, or vowel changes in the latter syllable. It was also studied if the ERPs were correlated with the amount of music played during the intervention or with the parents’ evaluations of their infant’s degree of prelinguistic development. The groups differed from each other in the auditory processing of the repetitive standard sound so that in the control group the ERPs had a different hemispheric pattern compared to the intervention groups and the repetitive sound was processed faster in the control group than in the instrumental group. It was also found that the hemispheric pattern of the ERPs for the vowel changes was different in the instrumental intervention group compared to the other groups. The parents’ evaluations of the prelinguistic development of their infant were correlated with the ERPs so that the ERPs to the repetitive standard stimuli were enhanced and reached their peak earlier in the infants who were evaluated to be more mature in their prelinguistic development. According to the results, the ERPs for the repetitive sounds are correlated with children’s linguistic development and an early musical intervention can modify the neural network processing speech sounds in infants with a genetic risk for dyslexia. In the future, it should be followed if these intervention effects on brain functions also enhance the linguistic development of the children and it should be also explored how other parts of the auditory environment of the children besides the intervention have possibly affected their auditory skills.
  • Partanen, Juulia (Helsingin yliopisto, 2017)
    Original antigenic sin (OAS) is an immunological phenomenon in which an initial antigen dominates the immune response toward subsequently encountered closely related antigens. As a result, the immune response against the primary antigen is boosted and a specific immune response toward the infecting antigen is attenuated in heterologous secondary infections. This may have various consequences, including aggravation of heterologous secondary infections, complication of vaccine development, and disturbance of serological diagnostics. This thesis is a literature review describing OAS in selected human viral infections and its clinical impact. A publication I worked on, demonstrating OAS in human bocavirus infections for the first time, is included. This thesis discusses what is known to date, limitations of past studies and gives recommendations for future research. Understanding OAS is necessary for the development of safe and effective vaccines and therapies, and accurate diagnostics for some of the most devastating infections of our time.
  • Rantala, Aleksi (Helsingin yliopisto, 2017)
    Objective: There is known to be a strong connection between hand movements and speech in humans. This has emerged for example in experiments where subjects pronounce syllables and simultaneously move their arm either towards or away from their body. The subjects produce both the hand movement and the pronunciation of syllables the fastest when the direction of the movement and the syllable are congruent. The original explanation for this was that the sounds that are congruent with the push movement, like [i] and [t], are made by pushing the tongue forward as well. Likewise, the sounds that are congruent with the pull movement, like [a] and [k], are made by a pull movement of the tongue. The objective of this study is to take a more precise look at this so-called direction-sound effect. The aim is to examine whether the effect is really caused by the overlap of the motor representations of hand and tongue, like it was originally interpreted, or if it is caused by some properties of sounds other than their horizontal movement direction. Methods: The direction-sound effect was studied in five experiments. In each experiment the subjects were presented with two different syllables, from which the other was supposed to be congruent with push hand movements and the other with pull hand movements. The subjects read each syllable out loud and performed simultaneously either a push or pull movement with a joystick according to the colour of the syllable. Experiments 1 and 2 tested whether the direction-sound effect emerges with consonants. Experiments 3, 4, and 5 tested whether the effect emerges when the vowels differ in one of their properties. In experiment 3 the vowels differed in openness, in experiment 4 they differed in frontness, and in experiment 5 in roundedness. 19-20 subjects participated in each experiment. Results and conclusions. In experiments 3 and 4 the syllables pronounced by the subjects, and the direction of their hand movement, had a statistically significant interaction to the reaction times of both the hand movements and the pronunciation of the syllables. There was not a similar interaction in experiments 1, 2, or 5. According to the results, vowels [ø] and [i] are congruent with the push hand movement and vowels [o] ja [æ] with the pull hand movement. The direction-sound effect does not seem to emerge with consonants but only with vowels. With vowels the effect seems to emerge when the vowels differ in their frontness and possibly in openness, but not when they differ in roundedness. The results bring more knowledge about how the speech movements of different parts of the mouth are represented when pronouncing vowels and consonants. The results also shed more light on previous speculations about which kind of sounds are universally associated with words referring to different directions across different languages.
  • Tiirikainen, Kati (Helsingin yliopisto, 2017)
    Anxiety disorders typically onset in adolescence, often resulting in significant impairment. Social anxiety disorder (SAD) and generalized anxiety disorder (GAD) are among the clinically most important anxiety disorders in adolescents and may have a significant effect on schoolwork. The aim of this study was to explore the associations of perceived difficulties in schoolwork with SAD and GAD. It also aimed at determining if the comorbidity between SAD and GAD is associated with higher rates of school difficulties than seen in SAD or GAD without comorbidity. The study also assessed if the associations are different for boys and girls, and whether parental education level, parental unemployment, family structure, and school performance explain the possible associations. The study data was based on the School Health Promotion Study of 2015 and included survey data from 37 905 Finnish upper secondary school students. Exploratory factor analysis was used to determine indicators for academic and social difficulties in school. Logistic regression analysis was used to examine the multivariate associations between anxiety symptoms and perceived difficulties in schoolwork, conducted separately for both genders. Three different logistic models were formed for each association, academic and social difficulties each being the dependent variable in turn. Each model had 1, 4, or 5 independent background variables, in addition to self-reported anxiety symptoms. The main finding of this study was that both social anxiety and general anxiety were associated with perceived difficulties in schoolwork in upper secondary school students. Adolescents with SAD or GAD had a significantly increased risk for difficulties in schoolwork. The comorbidity between SAD and GAD was associated with significantly higher rates of social difficulties than non-comorbid SAD or GAD. In academic difficulties, GAD especially increased the risk significantly whether or not it was comorbid with SAD. The associations were for the most part similar for boys and girls. Parental unemployment, low parental education level, other than nuclear family structure, and poor school performance were associated with school difficulties. However, those variables only explained a small proportion of the association between anxiety symptoms and school difficulties. This study showed that adolescents with anxiety symptoms face challenges that they probably need support for in the school environment.
  • Lempinen, Liisa (Helsingin yliopisto, 2017)
    Tiivistelmä – Abstrakt – Abstract Objectives: Previous studies have shown that psychotic-like experiences (PLE) have harmful effects on people’s lives, but there is no information on possible protecting effects of social support. The purpose of the current study was to examine in general population if social support protects against psychotic symptoms’ harmful effects. This study focused on the positive ones of psychotic symptoms whereas problems of daily living (ADL = activities of daily living) were selected to describe the harmful effects. Hypothesis was that the perceived social support decreases the risk of daily living problems, when sex, age, psychotic symptoms and the size of primary support group were controlled. Method: The data was obtained with face-to-face interviews in 2000 by the office for National Statistics (ONS). The name of the survey was The Second National Survey of Psychiatric Morbidity in Great Britain. Respondents were people living in private households, and aged between 16 and 74 years. The final sample size was 8464. Daily living problems were assessed from respondents’ answers to seven questions on difficulties in daily living. Psychotic symptoms were assessed using the Psychosis Screening Questionnaire (PSQ). The perceived social support was assessed from respondents’ answers to seven questions in the Health and Lifestyle Survey. The primary group size was assessed with three questions in the Interview Measure for Social Relationships (IMSR). Findings: It was found that the perceived social support predicted lower amount of daily living problems (OR: 0.91) after sex, age, psychotic symptoms, the size of the primary support group and interactions of these variables were controlled. Perceived social support is more important as a protecting factor against the psychotic symptoms’ harmful effects i.e. problems of daily living, than the size of the primary support group. Because this study wasn’t longitudinal, there is however not certainty of the perceived social support’s and the primary support group size’s protecting roles. Nevertheless, along this study it is now known that for general population’s part psychotic symptoms increase risk of daily living problems. Thus it should be important to survey the status of social support also for people with mild psychotic-like experiences, because it impacts their wellbeing in future.
  • Montgomery, Johanna (Helsingin yliopisto, 2017)
    Objectives: Previous studies have demonstrated that family environment can impact widely on children’s development, including their personality. Harsh home environments, such as negative parental child-rearing attitudes, can lead into negative developmental paths. Associations between childhood internalizing and externalizing problem behaviour and development of personality traits are less researched. However, behavioural styles of young children have been linked to their later mental health and personality style. The purpose of this study was to prospectively examine the effects of childhood problem behaviour and maternal child-rearing attitudes on development of negative emotionality and sociability traits. The hypotheses were that childhood problem behaviour and maternal negative child-rearing attitudes predict higher negative emotionality, lower sociability as well as changes in those traits at the second point of personality trait measurement. Methods: The participants (n = 1352) were derived from the longitudinal “Cardiovascular risk in Young Finns” study that began in 1980. Childhood problem behaviour and child-rearing attitudes were self-rated by the participants’ mothers’ in 1983, when the participants age varied from 6 to 21. The participants then self-rated their negative emotionality and sociability twice in 1992 and 1997, aged between 15 to 35. The associations between childhood problem behaviour, maternal child-rearing attitudes and the later personality traits were examined by linear regression analysis. Results and conclusions: Both internalizing and externalizing childhood problem behaviour were associated with higher level of negative emotionality in youth and early adulthood, but only internalizing behaviour predicted lower sociability. Surprisingly there were no associations between maternal child-rearing attitudes and personality trait development. Also, problem behaviour and child-rearing attitudes did not predict any trait changes at the second point of personality trait measurement. Knowledge about possible long-term effects of childhood problem behaviour on personality development can be utilized in preventative child and youth work.
  • Huhtinen, Saara (Helsingin yliopisto, 2017)
    Akuutin lymfoblastisen leukemian (ALL) hoito aiheuttaa monenlaisia ongelmia suun alueella. Syöpähoitojen aiheuttama kivulias mukosiitti vaikeuttaa hampaiden harjaamista, ja huonovointisuus ja ruokahalun heikkeneminen muuttavat ruokavaliota kariogeenisempaan suuntaan. Lisäksi syljeneritys vähenee. Nämä yhdessä johtavat reikiintymisriskin kohoamiseen. Tutkimuksen tarkoituksena oli kartoittaa lasten suun terveydentilaa ennen hoitoja, hoitojen aikana ja niiden jälkeen. Tutkimuksessa selvitettiin myös, miten hammashoito toteutui. Aineiston muodostivat vuosien 2005-2008 aikana alle 10-vuotiaana ALL:an sairastuneet lapset, joita hoidettiin HYKS Lastenklinikalla. Näitä potilaita oli yhteensä 50. Potilasasiakirjoista rekisteröitiin tarvittavat tiedot sairauskertomusten perusteella. Tutkimuksemme osoitti, että 77%:lla niistä potilaista, joilla ei ollut alkutarkastuksessa kariesta, ei ollut myöskään lopputarkastuksessa kariesta. Kariesriski näyttäisi olevan niillä lapsilla pienempi, joilla ei ennen syöpähoitojen alkamista esiinny kariesta. Aineiston potilaiden hammasterveydessä ei ollut suurta eroa yleisesti suomalaislasten hammasterveyteen. Hyvä lähtötilanne suun terveydessä suojaa myös hoitojen aiheuttamilta haasteilta. Huomion arvoista on myös se, että 20%:lla potilaista alkutarkastus jäi tekemättä. Tulos suuresta tarkastamattomien osuudesta johti siihen, että epäkohtaan on jo puututtu.
  • Lamberg, Sara (Helsingin yliopisto, 2017)
    Objectives. Autistic traits are normally distributed among general population and autism spectrum disorder can be thought to be in the other extreme end of the distribution. Preterm (<37 weeks) birth is a known risk factor for autism spectrum disorder and traits. Late preterm newborns (34+0- 36+6) are the fastest growing subset of neonates worldwide. The majority of preterm births occur between these gestational weeks. Late preterm birth has been linked to autistic traits in toddlers but there is no current research on whether these traits persist into adulthood. This study examines whether late preterm birth is also associated with self-assessed autistic traits in adulthood. The study also examines whether the participant’s birth weight relative to the length of gestation is a moderating factor for this association. Methods. The participants of this study are a part of the Arvo Ylppö Longitudinal Study follow-up cohort. The study sample comprised of 2193 infants whose gestational age was reliably specified and who filled in the Autism Spectrum Quotient (AQ) self report-questionaire. The final sample comprised of 684 participants of whom 90 were born late-preterm and 578 were born term. The effect of late-preterm birth to self-reported autistic traits was analyzed using linear regression models. Results and conclusions. Late preterm birth was not associated with increased risk of autistic traits in young adults. Neither was the relative birth weight a moderating factor for this association. More follow-up studies are needed to determine which are the specific factors contributing to autistic traits in specific age groups for different sub-categories of preterm birth. More information should be gathered about the potential confounding factors to determine which are the specific factors that may contribute to positive outcome.
  • Jonninen, Minna (Helsingin yliopisto, 2017)
    Aim. Attenuated positive psychotic symptoms, such as perceptual abnormalities and delusional ideas, are rather common in the general population not suffering from psychotic disorders. These psychotic-like experiences, or PLE, are usually transient and may be a common part of development of adolescents. However, there is also evidence that PLE may indicate a vulnerability to psychosis as well as other varied psychopathology, and a connection to need for care. There also seems to be differences between experiences in their impact. The current study aimed to investigate whether different types of PLE predicted further psychiatric treatment trajectories, or seeking outpatient treatment, in a seven-year follow-up using a psychiatric adolescent sample. Methods. The current study utilized a sample from the Helsinki Prodromal Study, a prospective study on psychosis risk. The sample (N=731) included adolescents aged 15–18, who had been referred to psychiatric care for the first time. The Prodromal Questionnaire (PQ), a self-report measure to assess psychosis risk symptoms, was administered to examine positive, negative, disorganized, and general symptoms of the participants at their first or second visit to the psychiatric unit. The outcome variable was a dichotomous measure of outpatient treatment starting after the completion of the PQ and assessed every year for seven consecutive years. Multilevel logistic regressions were carried out to investigate the predictive power of separate PLE and other psychosis risk symptoms. In addition, an area under the receiver operator characteristics curve was conducted to examine how the PQ total score distinguished between help-seekers and non-help-seekers in the second year of follow-up. Findings and conclusions. Of the nine psychosis risk factors that were assessed, eight predicted outpatient treatment over the follow-up, while Magical Thinking did not. There were no significant interactions between time and PLE, so these associations did not fluctuate over time. The PQ total score did not manifest as a reliable method for distinction of help-seekers in the second year of follow-up. However, these findings indicate that assessing PLE in clinical adolescent settings could help in predicting the further need for care.
  • Luukkanen, Henna (Helsingin yliopisto, 2017)
    Objectives. Specific language impairment (SLI) is a heterogeneous disorder varying in both symptom profile and severity and it often involves a variety of co-morbid problems. Language problems seem to be somewhat persistent until adolescence and adulthood but there is still little known about the wider long-term effects of the disorder. Information could help, for instance, in early identification and prevention of potential problems. The purpose of this study was to examine the impact of the childhood diagnosis of SLI on self-perceived quality of life and well-being of young adults aged 20–22 years. The focus was on the subjects’ self-perceived health-related quality of life and their own views on the effects of the SLI diagnosis on their lives. The study is part of a larger research project, which examines symptom profiles and longitudinal effects of childhood SLI. Methods. The study was carried out as a survey. The study sample consisted of persons who had received at Lastenlinna, the children’s hospital of Helsinki University Central Hospital, a primary diagnosis of specific language impairment (F80.1 expressive and/or F80.2 receptive language disorder) in 1998 or 1999. The survey consisted of a 15D questionnaire measuring health-related quality of life (HRQoL) and a separate SLI questionnaire which gathered other information relevant for the study. A total of 74 subjects answered the questionnaire resulting in a response rate of 38,5 percent. The data of the multiple-choice questions of the 15D and SLI questionnaires were analysed quantitatively by computing frequencies, averages, standard deviations and percentages of the answers and examining correlations between different variables. Answers of the open question were analysed using qualitative content analysis which brought forth some descriptive themes. Results and conclusions. The subjects perceived their HRQoL (15D) to be significantly worse off compared with age- and gender-matched control population which was apparent in the total 15D score and in several dimensions (hearing, sleeping, speech, usual activities, mental function, depression, distress and vitality). Subjects’ views on the effects of the SLI diagnosis on their lives were individual and varied, which reflects the heterogeneous nature of the disorder also from the perspective of the long-term effects. The effects of the SLI diagnosis extended to several areas of life, but the results included also positive effects and mitigation of problems. In the future additional research will be needed to, for instance, identify factors predicting long-term effects of SLI. The acquired information could help to focus the preventive supportive actions, rehabilitation and follow-up on children at greatest risk of negative long-term effects.
  • Holmström, Oscar; Linder, Nina; Lundin, Mikael; Moilanen, Hannu; Suutala, Antti; Turkki, Riku; Joensuu, Heikki; Isola, Jorma; Diwan, Vinod; Lundin, Johan (Helsingin yliopisto, 2015)
    Introduction: A significant barrier to medical diagnostics in low-resource environments is the lack of medical care and equipment. Here we present a low-cost, cloud-connected digital microscope for applications at the point-of-care. We evaluate the performance of the device in the digital assessment of estrogen receptor-alpha (ER) expression in breast cancer samples. Studies suggest computer-assisted analysis of tumor samples digitized with whole slide-scanners may be comparable to manual scoring, here we study whether similar results can be obtained with the device presented. Materials and methods: A total of 170 samples of hu-man breast carcinoma, immunostained for ER expression, were digitized with a high-end slide-scanner and the point-of-care microscope. Corresponding regions from the samples were extracted, and ER status was determined visually and digitally. Samples were classified as ER negative (<1% ER positivity) or positive, and further into weakly (1-10% positivity) and strongly positive. Interobserver agreement (Cohen’s kappa) was measured and correla-tion coefficients (Pearson’s product-momentum) were calculated for comparison of the meth-ods. Results: Correlation and interobserver agreement (r = 0.98, p < 0.001, kappa = 0.84, CI95% = 0.75-0.94) were strong in the results from both devices. Concordance of the point-of-care microscope and the manual scoring was good (r = 0.94, p < 0.001, kappa = 0.71, CI95% = 0.61-0.80), and comparable to the concordance between the slide scanner and man-ual scoring (r = 0.93, p < 0.001, kappa = 0.69, CI95% = 0.60-0.78). Fourteen (8%) discrepant cases between manual and device-based scoring were present with the slide scanner, and 16 (9%) with the point-of-care microscope, all representing samples of low ER expression. Con-clusions: Tumor ER status can be accurately quantified with a low-cost imaging device and digital image-analysis, with results comparable to conventional computer-assisted or manual scoring. This technology could potentially be expanded for other histopathological applications at the point-of-care.
  • Laine, Elina (Helsingin yliopisto, 2017)
    Tutkielma on kirjallisuuskatsaus aiheesta sepelvaltimotauti hampaanpoistopotilailla. Tutkimus pyrkii parantamaan potilasturvallisuutta ja vähentämään sydänsairaiden potilaiden suukirurgiseen hoitoon liittyvää epätietoisuutta kirurgiaa tekevien hammaslääkäreiden keskuudessa. Tieteelliset artikkelit kerättiin PubMed -tietokannasta. Tietoa haettiin myös oppikirjoista ja Terveysportti.fi internetsivustolta. Tutkielma painottuu hammaslääkärin vastaanotolla relevantteihin asioihin. Esiin nousevat potilaan lääkityksen ja mahdollisten leikkausten (pallolaajennus, ohitusleikkaus) sekä vierasaineiden (verisuonistentti, tahdistin) merkitys hampaan poiston yhteydessä. Erityisesti painottuen potilaan toimenpidekelpoisuuden ja yleisterveydentilan arviointiin erilaisia luokituksia hyödyntäen. Tutkielmassa käydään läpi myös antibioottiprofylaksian tarpeen punnitseminen, potilaan lääkityksien aiheuttamat riskit ja hoitoon liittyvien mahdollisten komplikaatioiden ennaltaehkäisy ja välttäminen, sekä ohjeistus siitä kuinka toimia akuutissa tilanteessa. Tietoa sepelvaltimotaudista on paljon. Hammaslääkärin vastuulle jää kuitenkin hammaslääketieteellisten suukirurgisten toimenpiteiden yhteydessä olennaisten yleislääketieteellisten asioiden ymmärtäminen ja riskien arvioiminen. Etenkin väestön vanhentuessa tulee peruskoulutetun hammaslääkärin omata riittävät valmiudet kohdata sydänsairaita potilaita. Tämän myötä kasvaa myös vastuu oman tiedon päivittämisestä.
  • Vesterinen, Essi (Helsingin yliopisto, 2017)
    Tämä tutkielma käsittelee verbimorfologian opettamista ranska vieraana kielenä -opetuksessa Suomes-sa. Tutkielman tarkoituksena on analysoida tekniikoita, joita suomessa käytetään verbimorfologian opet-tamiseen ja tarkastella, missä määrin sovelletut lähestymistavat ja tekniikat vastaavat sitä, mitä aikai-sempi tutkimus suosittaa käytettäväksi verbimorfologian opetuksessa. Tutkielmassa pitäydytään tarkas-telemaan indikatiivin preesensin opettamista. Tutkielmassa analysoidaan aluksi aikaisemman tutkimuk-sen perusteella sitä, mitä lähestymistapoja ja tekniikoita verbimorfologian opettamiseksi suositellaan. Sen jälkeen aikaisempaa tietoa verrataan sähköisellä kyselytutkimuksella kerättyyn tietoon opettajien käyttämistä menetelmistä verbimorfologian opettamisessa. Aikaisemman tutkimuksen valossa verbimorfologian opetuksessa suositellaan käytettävän pääosin im-plisiittisiä menetelmiä: Monet verbimuodot opitaan pääosin inputin avulla, eli sanavarasto kehittyy sitä mukaa, kun muotoja kuullaan ja nähdään toistuvasti ympäristössä. Vaikkei oppilas itse osaa vielä tuot-taa näitä muotoja, hän pystyy usein ymmärtämään niitä muiden taitojensa ja kontekstin avulla. Implisiitti-nen opetus suositellaan toteutettavan mahdollisuuksien mukaan autenttisten tehtävien kautta. Autenttisil-la tehtävillä tarkoitetaan aktiviteetteja, joilla on jokin konkreettinen tavoite, jonka saavuttamiseen vaadi-taan erilaisten, muidenkin kuin kielellisten, kompetenssien yhdistämistä. Oppimista voidaan nopeuttaa myös eksplisiittisillä harjoitteilla. Eksplisiittinen opetus tulisi toteuttaa induktiivisesti niin, että oppilaat muodostavat esimerkkien avulla oman käsityksensä rakenteiden säännönmukaisuuksista ja saavat pu-hua näistä käsityksistään omin termein. Kieliopillisia termejä ei siis välttämättä tarvitse käyttää, mutta olisi hyvä pyrkiä keskustelemaan mahdollisimman aikaisessa vaiheessa kohdekielellä. Perinteisen kol-meen luokkaan ja kirjoitettuun asuun pohjautuvan luokittelun sijaan tutkijat suosittavat opetuksessa käy-tettäväksi luokituksia, jotka pohjautuvat verbitaivutusten lausuttuihin muotoihin ja tarkemmin ottaen ver-bien erilaisten vartaloiden lukumäärään. Ennen kaikkea opetuksen tulisi tutkijoiden mielestä pohjautua enemmän lausuttuihin verbimuotoihin ja ääntämyksen ja kirjoitusasujen yhteys voitaisiin opetella vasta myöhemmän, esimerkiksi kotitehtävänä. Oppituntien rajoitettu aika tulisi mielellään käyttää mahdollisim-man pitkälti suullisiin harjoituksiin, joissa verbimuotoja opitaan kuulemaan ja käyttämään tosielämän tilanteita muistuttavissa konteksteissa ja sellaisenaan ilman kirjoitettua tukea. Tämän tutkimuksen perusteella Suomessa käytetyt opetusmenetelmät eivät aivan vastaa sitä, mitä tutki-jat aikaisemman tutkimuksen perusteella suosittelevat. Opetus pohjautuu usein eksplisiittisille opetus-menetelmille, jolloin input jää liian niukaksi. Eksplisiittisessä opetuksessa myös sovelletaan usein deduktiivista lähestymistapaa, jossa oppilaille tarjotaan valmis sääntö annettuna. Vallitseva luokitteluta-pa vaikuttaa olevan perinteinen verbien kirjoitettuihin asuihin pohjautuva kolmen luokan jako. Suullisia harjoituksia luokissa on paljon, mutta niissä käytetään yleensä apuna kirjallista tukea eivätkä ne vaikuta useinkaan kovin autenttisilta: Verbitaivutuksia toistetaan sellaisenaan irrallaan kontekstista. Tämän tut-kielman perusteella oppilaat voisivat hyötyä siitä, että inputin, erityisesti suullisen, määrää lisättäisiin oppitunneilla ja eksplisiittiset aktiviteetit teetettäisiin mahdollisuuksien mukaan kotitehtävänä. Eksplisiit-tiset tehtävät tulisi lisäksi toteuttaa niin, että oppilaan omat pohdinnat ja aktiivisuus on keskiössä.