The Efficacy of Modified Olfactory Training for MCI High-Risk Individuals

Официальное название

Assessing Modified Olfactory Training to Prevent Cognitive Decline in MCI High-Risk Individuals: A Randomized Controlled Trial Protocol

Обзор

The goal of this clinical trial is to validate the effectiveness of the modified olfactory training device, the main questions it aims to answer are: Is it possible that the device can delay the progression of MCI in older adults? Compared to the conventional device, how efficient is the modified olfactory training device for improving cognitive function?

Подробное описание

Mild Cognitive Impairment (MCI) represents an intermediary stage between normal aging and dementia, with a significant proportion of cases progressing to dementia. No simple and effective therapeutic strategies are available to halt or reverse this progression. Olfactory dysfunction, a common early clinical manifestation of neurodegenerative diseases such as Alzheimer's Disease (AD), often precedes cognitive decline. Subjective Cognitive Decline (SCD) is increasingly recognized as a prodromal stage of MCI and dementia, which, together with olfactory dysfunction, provides a critical window for early intervention.

Conventional olfactory training (COT) has been shown to improve olfactory function, cognitive abilities, and brain connectivity in healthy elderly individuals, suggesting its potential to enhance neuroplasticity. Preliminary studies indicate that modified olfactory training (MOT) may yield superior outcomes compared to COT, with higher rates of olfactory recovery and improved deposition in the olfactory fissure. However, the efficacy of MOT in delaying or preventing the progression of olfactory dysfunction to MCI remains unclear.

In this study, the investigators planned to recruit 114 patients and divided them into three groups for control group and olfactory training with conventional and modified devices, and validate the effectiveness of the modified device based on changes in cognitive function and the comparison of the outcomes of the three groups.

Вмешательства

• Комбинированный продукт Modified olfactory training device
  Participants will use a modified olfactory training device based on expiratory pressure. The advantages of the improved device are as follows: bi-directional airflow, positive pressure and the function of voice prompts and automatic counting.
• Комбинированный продукт Conventional olfactory training device
  This device involves four brown glass jars (total volume 5 mL) with one of the four odors in each (1mL each, soaked in cotton pads to prevent spilling). The following odors were used: phenyl ethyl alcohol (PEA): rose, menthol: mint, citronellal: lemon, and eugenol: cloves. All jars were labeled with the odor name.

Первичные конечные точки

• Montreal Cognitive Assessment (MoCA) score [Срок оценки: Baseline,Month 3,Month 6,Month 12,Month 24]
• Biomarkers of cognition (Blood/CSF) [Срок оценки: Baseline,Month 3,Month 6,Month 12,Month 24]
• Neuroimaging assessments [Срок оценки: Baseline,Month 3,Month 6,Month 12,Month 24]
• The Sniffin' Sticks test [Срок оценки: Baseline,Month 3,Month 6,Month 12,Month 24]

Вторичные конечные точки (12)

• Auditory Verbal Learning Test (AVLT) [Срок оценки: Baseline,Month 3,Month 6,Month 12,Month 24]
• Digit Span Test (DST) [Срок оценки: Baseline,Month 3,Month 6,Month 12,Month 24]
• Trail Making Test (TMT) [Срок оценки: Baseline,Month 3,Month 6,Month 12,Month 24]
• Clock Drawing Test (CDT) [Срок оценки: Baseline,Month 3,Month 6,Month 12,Month 24]
• Boston Naming Test (BNT) [Срок оценки: Baseline,Month 3,Month 6,Month 12,Month 24]
• Verbal Fluency Test (VFT) [Срок оценки: Baseline,Month 3,Month 6,Month 12,Month 24]
• Activities of Daily Living Scale (ADL) [Срок оценки: Baseline,Month 3,Month 6,Month 12,Month 24]
• Instrumental Activities of Daily Living (IADL) [Срок оценки: Baseline,Month 3,Month 6,Month 12,Month 24]
• Neuropsychiatric Inventory (NPI) [Срок оценки: Baseline,Month 3,Month 6,Month 12,Month 24]
• Hamilton Anxiety Scale (HAMA) [Срок оценки: Baseline,Month 3,Month 6,Month 12,Month 24]
• Hamilton Depression Scale (HAMD) [Срок оценки: Baseline,Month 3,Month 6,Month 12,Month 24]
• Olfactory bulb volume [Срок оценки: Baseline,Month 3,Month 6,Month 12,Month 24]

Критерии участия

Критерии включения

• Age and Gender: Individuals aged 60-80 years, regardless of gender.
• Diagnosis of Idiopathic Olfactory Dysfunction: overall TDI score below 30.75 points using the Sniffin' Sticks test. Without olfactory impairment due to traumatic, sinusitis-related, congenital, toxic/drug-induced causes, post-operative conditions, tumors, or post-upper respiratory infections.
• Diagnosis of Subjective Cognitive Decline: Montreal Cognitive Assessment (MoCA) score >24 for middle school level and above, >19 for elementary school level, and >13 for illiterate individuals. Amyloid β (Aβ) deposition in the brain (defined as Aβ42 < 550 ∼ 813 pg/ml)， the higher Formula of Hulstaert (defined as \[(Aβ42/(240 + 1.18 × tau) ≤1\]）, and hippocampus atrophy.
• Consent: Willingness to sign an informed consent form.

Критерии исключения

• Comorbid Chronic Diseases or Severe Concurrent Illnesses: Individuals with conditions such as hypertension, diabetes, bronchopneumonia, malignant tumors， or chronic obstructive pulmonary disease.

4\. Recent Medication Use: Exclusion of participants who have taken corticosteroids, antimicrobials, leukotriene antagonists, or antihistamines within the last four weeks.

5\. Inability to Comply with Study Requirements: Based on the researcher's judgment, individuals who are unable to tolerate olfactory function tests and treatment， complete the study or comply with its requirements due to memory or behavioral abnormalities, depression, severe alcohol consumption, or previous non-compliance.

Критерии приведены из реестра в оригинале (на английском). Окончательную оценку соответствия проводит исследовательский центр.

Здоровые добровольцы: Нет

Дизайн исследования

Распределение

Рандомизированное

Модель

Параллельные группы

Маскирование

Тройное слепое

Основная цель

Профилактика

Центры проведения

Китай · 1 центр

• Dawei Wu — Пекин

Публикации

• Lin CY, Tan Y, Zhao D, Wu D. Assessing modified olfactory training to prevent cognitive decline in MCI high-risk individuals: a multicentre randomised controlled trial protocol in Beijing tertiary hospitals. BMJ Open. 2025 Aug 13;15(8):e100880. doi: 10.1136/bmjopen-2025-100880. PMID 40812823

Идентификаторы

NCT: NCT06821828 · 9059101

Первоисточники (государственные реестры)

• ClinicalTrials.gov (NIH, США)

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