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Cochrane Database of Systematic Reviews

L‐carnitina para la estimulación cognitiva en personas sin deterioro cognitivo

Información

DOI:
https://doi.org/10.1002/14651858.CD009374.pub3Copiar DOI
Base de datos:
  1. Cochrane Database of Systematic Reviews
Versión publicada:
  1. 26 marzo 2017see what's new
Tipo:
  1. Intervention
Etapa:
  1. Review
Grupo Editorial Cochrane:

  1. Grupo Cochrane de Demencia y trastornos cognitivos

Copyright:
  1. Copyright © 2017 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.

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Autores

  • Ning Chen

    Department of Neurology, West China Hospital, Sichuan University, Chengdu, China

  • Mi Yang

    Department of Neurology, West China Hospital, Sichuan University, Chengdu, China

  • Muke Zhou

    Department of Neurology, West China Hospital, Sichuan University, Chengdu, China

  • Jing Xiao

    Department of Neurology, West China Hospital, Sichuan University, Chengdu, China

  • Jian Guo

    Department of Neurology, West China Hospital, Sichuan University, Chengdu, China

  • Li He

    Correspondencia a: Department of Neurology, West China Hospital, Sichuan University, Chengdu, China

    [email protected]

Contributions of authors

Ning Chen and Mi Yang: wrote the draft of the review.

Muke Zhou, Ning Chen, Jian Guo, Jing Xiao: performed data collection, methodological quality assessment, and analyses.

Li He: the corresponding author, developed the proposal, offered expert advice, reviewed and revised the draft, and is responsible for developing and updating the review.

Sources of support

Internal sources

  • No sources of support supplied

External sources

  • National Institute for Health Research (NIHR), UK.

    This review was supported by the National Institute for Health Research (NIHR), via Cochrane Infrastructure funding to the Cochrane Dementia and Cognitive Improvement Group. The views and opinions expressed herein are those of the authors and do not necessarily reflect those of the Systematic Reviews Programme, NIHR, National Health Service (NHS), or Department of Health.

Declarations of interest

Ning Chen: None known.
Mi Yang: None known.
Muke Zhou: None known.
Jing Xiao: None known.
Jian Guo: None known.
Li He: None known.

Acknowledgements

We are grateful for the assistance of Sue Marcus, Managing Editor; Anna Noel‐Storr, Information Specialist; and other editors of the Cochrane Dementia and Cognitive Improvement Group.

Version history

Published

Title

Stage

Authors

Version

2017 Mar 26

L‐carnitine for cognitive enhancement in people without cognitive impairment

Review

Ning Chen, Mi Yang, Muke Zhou, Jing Xiao, Jian Guo, Li He

https://doi.org/10.1002/14651858.CD009374.pub3

2015 Nov 14

L‐carnitine for cognitive enhancement in people without cognitive impairment

Protocol

Ning Chen, Mi Yang, Muke Zhou, Jing Xiao, Jian Guo, Li He, Ruxin Xing

https://doi.org/10.1002/14651858.CD009374.pub2

2011 Nov 09

L‐carnitine for cognition in healthy subjects

Protocol

Mi Yang, Muke Zhou, Jing Xiao, Ning Chen, Jian Guo, Li He, Ruxin Xing

https://doi.org/10.1002/14651858.CD009374

Differences between protocol and review

We planned to calculate a weighted treatment effect using a fixed‐effect model or a random‐effects model across trials, but no treatment effect across trials could be calculated because there was not enough relevant data.

For missing data, we planned to use an intention‐to‐treat method or include per protocol data, but neither was done because there was insufficient information.

We planned to conduct sensitivity analyses, heterogeneity assessment, and subgroup analyses, but these were not done because only two trials were included and no meta‐analysis could be performed.

We planned to construct a 'Summary of findings' table and to include the results for global cognitive function, memory, executive function, and adverse effects. However, according to the available data from a single study (Benton 2004), we presented the results for reaction time, vigilance, immediate memory, delayed memory, and adverse effects in the 'Summary of findings' table.

Notes

The protocol was first published in Issue 11, 2011 of the Cochrane Library (Yang 2011), but the title and types of participants have been changed in the updated protocol and review to make the objectives of the review clearer.

Keywords

MeSH

Medical Subject Headings (MeSH) Keywords

Medical Subject Headings Check Words

Humans; Young Adult;

PICO

Population
Intervention
Comparison
Outcome

El uso y la enseñanza del modelo PICO están muy extendidos en el ámbito de la atención sanitaria basada en la evidencia para formular preguntas y estrategias de búsqueda y para caracterizar estudios o metanálisis clínicos. PICO son las siglas en inglés de cuatro posibles componentes de una pregunta de investigación: paciente, población o problema; intervención; comparación; desenlace (outcome).

Para saber más sobre el uso del modelo PICO, puede consultar el Manual Cochrane.

Study flow diagram.
Figuras y tablas -
Figure 1

Study flow diagram.

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Risk of bias summary: review authors' judgements about each risk of bias item for each included study.
Figuras y tablas -
Figure 2

Risk of bias summary: review authors' judgements about each risk of bias item for each included study.

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Summary of findings for the main comparison. L‐carnitine compared to placebo for cognitive enhancement in people without cognitive impairment

L‐carnitine compared to placebo for cognitive enhancement in people without cognitive impairment

Patient or population: healthy young women
Setting: community
Intervention: L‐carnitine
Comparison: placebo

Outcomes

Anticipated absolute effects* (95% CI)

№ of participants
(studies)

Quality of the evidence
(GRADE)

Comments

Risk with placebo

Risk with L‐carnitine

Reaction time (8 lamps)
Assessed with: reaction time task with 8 potentially illuminated lamps
Follow‐up: mean 3 days

The mean reaction time (8 lamps) was 416 milliseconds

MD 5 milliseconds fewer
(23.18 fewer to 13.18 more)

200
(1 RCT)

⊕⊝⊝⊝
VERY LOW 1 2 3

The number of participants was an approximation, since the report did not specify the actual numbers of participants in each study group.

Vigilance
Assessed with: rapid information‐processing task
Follow‐up: mean 3 days

The mean vigilance was 23.5 digits

MD 1.2 digits fewer
(3.06 fewer to 0.66 more)

200
(1 RCT)

⊕⊝⊝⊝
VERY LOW 1 2 3

Immediate memory
Assessed with: recall of word list
Scale from: 0 to 30
Follow‐up: mean 3 days

The mean immediate memory was 11.6 words

MD 1 words fewer
(2.07 fewer to 0.07 more)

200
(1 RCT)

⊕⊝⊝⊝
VERY LOW 1 2 3

Delayed memory
Assessed with: recall of word list
Scale from: 0 to 30
Follow‐up: mean 3 days

The mean delayed memory was 8.9 words

MD 0.9 words fewer
(1.97 fewer to 0.17 more)

200
(1 RCT)

⊕⊝⊝⊝
VERY LOW 1 2 3

Adverse effects ‐ not reported

It stated that 92% of participants reported no side effects and that the numbers of participants who had some minor reaction were similar among the experimental groups, but the actual number of participants reporting any adverse effect in each group is unknown.

—

⊕⊝⊝⊝
VERY LOW 1 2 3

*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).

CI: confidence interval; MD: mean difference; RCT: randomised controlled trial

GRADE Working Group grades of evidence
High quality: We are very confident that the true effect lies close to that of the estimate of the effect.
Moderate quality: We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different.
Low quality: Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect.
Very low quality: We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect.

1Downgraded one level due to study limitations. Most of the 'Risk of bias' judgements were 'unclear', so we considered there to be a serious concern about risk of bias.
2Downgraded one level due to indirectness. The follow‐up period to observe the change in cognitive function in people without cognitive impairment was very short.
3Downgraded one level due to imprecision. The results came from a single, small study.

Figuras y tablas -
Summary of findings for the main comparison. L‐carnitine compared to placebo for cognitive enhancement in people without cognitive impairment
Ir a la tabla de la revisión