Željko Zubčić
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Željko Zubčić has a total of 22 co-authors. Here are the top co-authors by number of shared publications:
- Jelena Šarić Jurić
Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, Croatia
2 shared publications - Mirjana Grebenar Čerkez
Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, Croatia
2 shared publications - Stjepan Jurić
Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, Croatia
2 shared publications - Anamarija Šestak
Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, Croatia
1 shared publication - Andrijana Včeva
Department of Otorhinolaryngology and Maxillofacial Surgery, Faculty of Medicine, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, Croatia
1 shared publication - Branko Dmitrović
Faculty of Dental Medicine and Health Osijek, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
1 shared publication
Latest Publications
- Open Access
- 23 November 2025
- Published by MDPI AG in Journal of Clinical Medicine
- Vol. 14 (23) , 8319
Neurocognitive Recovery Following Continuous Positive Airway Pressure Therapy in Patients with Moderate to Severe Obstructive Sleep Apnea
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.
- 23 November 2025
- Published by MDPI AG in Journal of Clinical Medicine
- Vol. 14 (23) , 8319
Open AccessNeurocognitive Recovery Following Continuous Positive Airway Pressure Therapy in Patients with Moderate to Severe Obstructive Sleep Apnea
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.
- Open Access
Effect of Continuous Positive Airway Pressure Treatment on Hearing and Inner Ear Function in Patients with Obstructive Sleep Apnoea—Original Research
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.
Open AccessEffect of Continuous Positive Airway Pressure Treatment on Hearing and Inner Ear Function in Patients with Obstructive Sleep Apnoea—Original Research
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.
- Open Access
- 30 November 2023
- Published by MDPI AG in Journal of Clinical Medicine
- Vol. 12 (23) , 7425
Laryngopharyngeal Reflux Scoring in a Pediatric Population
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.
- 30 November 2023
- Published by MDPI AG in Journal of Clinical Medicine
- Vol. 12 (23) , 7425
Open AccessLaryngopharyngeal Reflux Scoring in a Pediatric Population
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.