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In addition to the visual information, external light causes non-image-forming (NIF) effects that modulate brain function and induce psychophysiological effects. The light signal is traditionally assumed to only be mediated via the eyes. Recent studies have suggested the existence of putatively light sensitive structures in the rodent and human brain and penetration of light into the skull and brain tissue has been observed. The brain activation observed during transcranial bright light (TBL) exposure indicates a direct light responsivity of brain tissue. The aim of this thesis was to explore the psychophysiological responses related to TBL. The studies comprising this thesis were conducted in healthy subjects and patients suffering from seasonal affective disorder. TBL exposure was administered via the ear canals in all study settings using light-emitting diodes (LEDs). The comparisons in studies I, II, and III were conducted against the inactivated sham device. Study IV explored the effect of TBL dose. Neither melatonin nor cortisol secretions were altered when acutely exposed to nocturnal TBL. Circadian profiles in TBL setting were in parallel to control conditions for both hormones. Intermittent TBL exposure led to alleviation of jet lag symptoms. Overall post-travel jet lag symptoms as well as subjective feelings of fatigue, inertia, and forgetfulness were reduced. The time to execute the motor response i.e. motor time with a visual warning signal was improved by the TBL treatment. TBL alleviated both depressive and anxiety symptoms related to seasonal affective disorder (SAD). A dose-response relationship regarding the intensity of dose administered via the ear canals was not found. Altogether, TBL seems to affect human brain function by alleviating symptoms of jet lag and SAD and improving psychomotor performance. The acute effect is suggested to be mediated via structures unrelated to acute melatonin secretion i.e. the retinohypotalamic tract (RHT)., Tiivistelmä Visuaalisen informaation lisäksi valo aiheuttaa käytöksellisiä ja fysiologisia vaikutuksia, jotka eivät liity kuvan muodostamiseen. Yleisesti vaikutuksen ajatellaan välittyvän aivoihin ainoastaan silmien kautta. Viimeaikaiset tutkimukset ovat havainneet jyrsijöiden ja ihmisten aivoissa mahdollisesti valolle vasteellisia rakenteita. Valon on osoitettu lisäksi läpäisevän kallon ja saavuttavan aivokudoksen. Aivojen aktivoituminen kallon läpi annettavan valoaltistuksen aikana viittaa myös suoraan aivojen valovasteellisuuteen. Tämän väitöskirjan tavoitteena oli tarkastella vaikuttaako kallon läpi annettava valo ihmisen psykofysiologiaan. Tähän väitöskirjaan sisällytetyt tutkimukset tehtiin terveillä vapaaehtoisilla tutkittavilla ja kaamosmasennuspotilailla. Ledin avulla tuotettu valo annettiin kaikissa tutkimusasetelmissa korvakäytävien kautta. Tutkimukset I, II ja III tehtiin lumekontrolliasetelmassa. Tutkimuksessa IV tarkasteltiin valon annosvastetta. Akuutin yöaikaisen valoaltistuksen ei havaittu muuttavan melatoniinin tai kortisolin eritystä. Molempien hormonien vuorokausieritysprofiilit olivat kontrolliasetelman kaltaiset. Jaksottaisen valoaltistuksen havaittiin lievittävän aikaerorasituksen kokonaisoireita ja vähentävän väsymystä, inertiaa ja hajamielisyyttä. Motorisen nopeuden havaittiin paranevan kolmen viikon valohoitojakson aikana. Lisäksi neljän viikon valohoitojakso lievitti kaamosmasennukseen liittyviä masennus- ja ahdistusoireita. Vaikutuksessa ei havaittu eroa eri valoannoksen saaneiden ryhmien välillä. Kallon läpi annettava kirkasvalo näyttäisi vaikuttavan ihmisen aivotoimintaan lievittämällä aikaerorasituksen ja kaamosmasennuksen oireita sekä parantamalla psykomotorista suorituskykyä. Vaikutus ei ole yhteydessä akuuttiin melatoniinin erityksen estämiseen. Tämän tutkimuksen tulokset tukevat ajatusta aivojen valovasteellisuudesta. Kallon kautta annettavan valon vaikutusmekanismia ei kuitenkaan tiedetä vielä.

OBJECTIVE: Patients with type 1 diabetes (T1D) have an increased risk of cognitive dysfunction. The cognitive decrement is believed to depend on macro- and microvascular complications and long disease duration. Some patients do not develop these complications, but still report cognitive symptoms. We examined if long-standing T1D without complications is associated with lower cognitive performance. METHODS: A group of patients (n=43) with long-standing T1D (>30years) without micro- or macro vascular complications was compared with a non-diabetic control group (n=86) on six cognitive tests which probed episodic memory, semantic memory, episodic short-term memory, visual attention and psychomotor speed. Each patient was matched with two controls regarding age, gender and education. A linear mixed effect model was used to analyze the data. RESULTS: The mean age was 57years and mean duration was 41years. Patients with diabetes had lower diastolic blood pressure but BMI, waist circumference, systolic blood pressure and smoking did not differ between groups. Patients had lower results than non-diabetic controls in episodic short-term memory (p<0.001) and also lower values on a test that mirrors visual attention and psychomotor speed (p=0.019). CONCLUSIONS: Long-standing T1D was associated with lower cognitive performance, regardless of other diabetes-related complications.

Objectives: Slowing of the central information-processing speed (CIPS) is frequently observed in epilepsy as a consequence of epileptic seizures and/or antiepileptic drugs (AEDs). A variety of neuropsychological tests are used to asses this ‘mental slowing,’ but it is highly questionable whether the different tasks measure the same cognitive process. Also, it remains unspecified to which degree the various tasks are sensitive to seizure- or treatment-related factors, or both. Methods: We used an open clinical non-comparative study design. The sample consisted of adult patients with cryptogenic localization-related epilepsy who performed different cognitive measures of CIPS and psychomotor speed (PmS). Clinical data about their seizures and antiepileptic drug treatment were collected from an electronic patient database. Results: Eighty patients were included. CIPS tasks mutually correlated significantly, but did not correlate with measures of PmS (finger tapping and reaction time). Also, the CIPS tasks were differently affected by treatment and seizure effects. Processing of complex information is affected by tonic–clonic seizures, while less complex tasks are more sensitive for AED effects. Conclusions: CIPS tasks are mainly measuring central processing, and the psychomotor component of these tasks is negligible. We propose a psychometric continuum on which PmS and CIPS tasks are ordered with ascending complexity. The model shows that the tasks are affected differently by seizures, treatment, age, and education level. In neuropsychological practice, this continuum can be helpful in the detection of treatment and seizure effects on the CIPS in epilepsy.

Objectives: Slowing of the central information-processing speed (CIPS) is frequently observed in epilepsy as a consequence of epileptic seizures and/or antiepileptic drugs (AEDs). A variety of neuropsychological tests are used to asses this ‘mental slowing,’ but it is highly questionable whether the different tasks measure the same cognitive process. Also, it remains unspecified to which degree the various tasks are sensitive to seizure- or treatment-related factors, or both. Methods: We used an open clinical non-comparative study design. The sample consisted of adult patients with cryptogenic localization-related epilepsy who performed different cognitive measures of CIPS and psychomotor speed (PmS). Clinical data about their seizures and antiepileptic drug treatment were collected from an electronic patient database. Results: Eighty patients were included. CIPS tasks mutually correlated significantly, but did not correlate with measures of PmS (finger tapping and reaction time). Also, the CIPS tasks were differently affected by treatment and seizure effects. Processing of complex information is affected by tonic–clonic seizures, while less complex tasks are more sensitive for AED effects. Conclusions: CIPS tasks are mainly measuring central processing, and the psychomotor component of these tasks is negligible. We propose a psychometric continuum on which PmS and CIPS tasks are ordered with ascending complexity. The model shows that the tasks are affected differently by seizures, treatment, age, and education level. In neuropsychological practice, this continuum can be helpful in the detection of treatment and seizure effects on the CIPS in epilepsy.

Background: Self-care requires that patients learn to care for themselves. Cognitive impairment and depression can decrease the ability and interest in performing self-care. The objectives were to explore the association between cognitive function and self-care in heart failure patients, and to examine if this association was moderated by symptoms of depression. Methods: This cross-sectional study included 105 heart failure patients in NYHA II-IV, median age 72 years. Self-care was measured with the European Heart Failure Self-Care Behavior Scale, cognitive function with a neuropsychological battery, and depressive symptoms were measured with the Patient Health Questionnaire. The associations between the study variables were examined with multiple regression analyses. Results: Psychomotor speed was the only cognitive dimension significantly associated with self-care. The association between psychomotor speed and self-care was not moderated by symptoms of depression. Conclusions: Deficits in psychomotor speed have implications for how patients should be educated and supported to perform self-care.

Aim: To test the relationship between cognitive function and self-care in patients with heart failure after adjusting for the contribution of age, education, functional status, myocardial stress, sleep and depression. Further, the relationship between cognitive function and self-care was explored with depression and sleep as moderators. Background: Self-care can significantly impact functional capacity, well-being, morbidity, and prognosis in patients with heart failure (HF). However, self-care requires the cognitive ability to learn, perceive, interpret and respond. The influence of demographics and clinical symptoms on the relationship between cognition and self-care needs to be further understood. Design: Descriptive, cross-sectional study. Methods: The study included 142 patients with chronic HF (68% male, median age 72 years, 61% in NYHA II). Self-care was measured with the European Heart Failure Self-Care Behavior Scale. Cognitive function was evaluated with neuropsychological tests measuring global cognitive dysfunction, psychomotor speed, executive function, visual-spatial perception/construct, spatial performance, semantic and episodic memory. Findings: Psychomotor function (speed and attention) measured with the Trail Making A was the only dimension of cognitive function significantly associated with self-care. Neither depressive symptoms, nor sleep disturbances moderated the relation between cognitive function and selfcare. Conclusion: Deficits in psychomotor speed have implications for how patients should be educated and supported to perform self-care. A decrease in sustained attention and ability to carry out more than one task at a same time could lead to difficulties in self-care. Screening for psychomotor speed is therefore advocated for patients with HF.

Thirteen asymptomatic HIV-infected (HIV+) and 13 healthy control (HIV-) subjects were instructed to detect 'oddball'; target tones from among a sequence of nontarget tones delivered rapidly (3 tones/sec) in one ear while ignoring a similar sequence delivered simultaneously in the opposite ear. Event-related potentials (ERPs) to all stimuli were recorded from midline scalp sites. Both groups produced ERP correlates, termed the mismatch negativity (MMN), to the oddball tones during delivery. However, the HIV+ group produced MMNs that were different in morphology to the HIV- group, suggesting that HIV may alter attentional perceptual processing. These results suggested that auditory ERPs elicited by rapid, dichotic stimulus presentations may be useful tools in monitoring subclinical effects of HIV-related neuropathology on perceptual processing.