Željko Zubčić

Dr. Željko Zubčić


Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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23 November 2025 in Journal of Clinical Medicine
Verified
Journal Article
Open access
PDF file
JJJelena Saric Juric
Jelena Saric Juric
MČMirjana Grebenar Čerkez
Mirjana Grebenar Čerkez
ŽZŽeljko Zubčić
Željko Zubčić
SBSilvio Basic
Silvio Basic
IBIvana hospital Basic
Ivana hospital Basic
SJStjepan Juric
Stjepan Juric
Background/Objectives: Obstructive sleep apnea (OSA) is a common sleep-related breathing disorder associated with cognitive decline. Evidence regarding the reversibility of these deficits after continuous positive airway pressure (CPAP) therapy remains inconsistent. Methods: This prospective observational study included 60 adults with newly diagnosed moderate-to-severe OSA (median age 51 years; 80% male), who underwent baseline assessment using P300 event-related potentials and the Montreal Cognitive Assessment (MoCA). After three months of CPAP therapy with confirmed good compliance, both measures were re-evaluated. Results: After three months of CPAP therapy, a statistically significant reduction in P300 latency (p < 0.001) and an increase in amplitude were observed, accompanied by significant improvements in executive function (p < 0.001), attention (p < 0.001), and delayed recall (p < 0.001). Conclusions: CPAP therapy leads to measurable recovery of cognitive function in patients with moderate-to-severe OSA, suggesting partial reversibility of neurocognitive impairment associated with sleep-disordered breathing. These findings highlight the importance of early recognition and treatment of OSA to prevent long-term cognitive decline.

30 November 2023 in Journal of Clinical Medicine
Verified
Journal Article
Open access
PDF file
IAIvan Abičić
Ivan Abičić
MCMarina Covic
Marina Covic
MZMilorad Zjalić
Milorad Zjalić
MBMarina Bakula
Marina Bakula
KMKsenija Marjanović
Ksenija Marjanović
AVAndrijana Včeva
Andrijana Včeva
In recent years, the prevalence of laryngopharyngeal reflux has risen, especially among pediatric patients. The diagnosis of laryngopharyngeal reflux relies on patient history and clinical assessment using the Reflux Finding Score and Reflux Symptom Index as crucial diagnostic tools. Some studies have proposed a link between pepsin and laryngopharyngeal reflux, potentially triggering palatine tonsil hypertrophy. Our study aimed to investigate the correlation between laryngeal and pharyngeal manifestations of laryngopharyngeal reflux through two questionnaires and the presence of pepsin in saliva and palatine tonsils in a pediatric population. Pepsin in saliva was detected using a Western blot method, while immunohistochemistry assessed its presence in palatine tonsils. Although no statistically significant differences in Reflux Finding Score and Reflux Symptom Index were found between the immunohistochemistry-positive (IHC-positive) and immunohistochemistry-negative (IHC-negative) groups, median reflux symptom index and Reflux Finding Score values consistently trended higher in the IHC-positive group. This suggests a potential connection between elevated index values and pepsin presence in tonsillar tissue. Further investigations are essential to fully comprehend the clinical implications of these findings.

14 October 2025 in Medicina
Verified
Journal Article
Open access
PDF file
MČMirjana Grebenar Čerkez
Mirjana Grebenar Čerkez
ŽZŽeljko Zubčić
Željko Zubčić
SJStjepan Juric
Stjepan Juric
JJJelena Saric Juric
Jelena Saric Juric
JKJelena Kovačević
Jelena Kovačević
DBDarija Birtic
Darija Birtic
Background and Objectives: This study aimed to investigate the influence of continuous positive airway pressure in patients with obstructive sleep apnoea on hearing and the possibility of recovering cochlear receptor cells. Materials and Methods: Forty-two patients with obstructive sleep apnoea (OSA) were assigned to the study group. Patients underwent pure-tone audiometry and transient-evoked (TEOAE) and distortion-product (DPOAE) otoacoustic emissions before starting continuous positive airway pressure (CPAP) therapy and six months after CPAP therapy. Subjects were further divided into the following two groups: those who adequately used the therapy and those who did not adhere to treatment recommendations. Results: There is no significant difference in hearing thresholds for specific frequencies after six months of CPAP therapy. There is no significant difference in TEOAE and DPOAE SNR values at any frequency after 6 months of CPAP therapy. There is no significant difference in hearing threshold results for specific frequencies as a function of subject co-operation with treatment. After therapy, there is a significant difference in the SNR values in TEOAEs at 2 kHz and 4 kHz in subjects of the OSA target group, depending on co-operation, being higher in co-operative subjects, while there are no significant differences at other frequencies. There is a significant difference in the SNR results in DPOAEs, where they are higher in co-operative subjects at 1000, 6000, 7000 and 8000 Hz. Conclusions: The use of continuous positive airway pressure as a therapy for OSA has no effect on hearing and cochlear receptor cell recovery. Co-operation with CPAP treatment does not affect hearing threshold, but does affect cochlear receptor cell function, which is better at mid and higher frequencies in those who co-operate. These findings underscore the clinical significance of treatment adherence. Consistent adherence is associated with measurable improvements in hearing, particularly at higher frequencies, which cannot typically be evaluated in routine clinical practice using standard pure-tone audiometry. Our results emphasise the importance of promoting compliance with CPAP therapy not only for cardiovascular and neurological protection, but also for maintaining hearing health.