The question of how “consciousness” can be scientifically investigated is extraordinarily complex. It cannot be answered from a neuroscientific, psychological or philosophical point of view alone. Even the object of such an investigation becomes blurred in the arbitrariness of the understanding of what consciousness is. As early as 1913, the psychologist Watson came to the conclusion that concepts such as consciousness were unscientific ballast that had no place in science. “For the representatives of such psychologies “…do not tell us what consciousness is, but simply begin to put something into it” (Watson 1968). This criticism has not become obsolete even today.

A serious scientific examination of the question of what consciousness, subjective sensations and the like are, and what their neurobiological correlates are, must try to adequately specify these concepts and indicate the criteria by which it can be determined whether a human or animal performance is conscious or accompanied by a subjective experience, or whether it is a performance that takes place without consciousness or subjective sensation. Only this specification is a prerequisite for the fact that the neurobiological processes that characterize consciousness can be scientifically investigated and that the neurobiological processes that characterize consciousness become recognizable at all.

The concept of consciousness was clarified within the framework of methodological and neuropsychological investigations. In brain-damaged patients it was shown how the development of a conscious visual impression can be quantitatively measured in contrast to an unconscious processing of visual stimuli in the brain and which are the underlying neuronal processes. The results were described in :

R. Werth:

Berlin Heidelberg New York Tokyo




Die Natur des BewusstseinsR. Werth:
Die Natur des Bewusstseins

Verlag C.H. Beck
Wie Wahrnehmung und freier Wille im Gehirn entstehen



One of the most difficult to comprehend changes in consciousness that can be triggered by brain damage is the lack of awareness of the existence of one half of the room and/or body, a disorder known as “neglect”. The patients no longer direct their head and eyes into one half of the room, objects in this half of the room are ignored as if they did not exist. Thus, for example, only food is eaten on the right half of a plate, while drawing an object, its left side is not displayed. Patients do not wash or dress one half of their body and shave only one half of their face. They are not able to find the arm of one half of the body or an object e.g. to the left of it. They do not express themselves about one half of a room and/or body and do not seem to understand other people’s expressions about one half of a room or about one of their body halves. Despite normal intelligence, the patients behave as if one half of the room and/or body had ceased to exist. Within the framework of a research project, the diagnostic criteria for this disorder were specified, the numerous different phenomena in which the disorder is expressed and the neuronal basis of the disorder were investigated. The results have been described in :

Neglect nach Hirnschädigung, ISBN 978-3-662-08930-9
Unilaterale Verminderung der Aufmerksamkeit und Raumrepräsentation

R. Werth:
Neglect nach Hirnschädigung

Unilaterale Verminderung der Aufmerksamkeit und Raumrepräsentation

Verlag C. H. Beck
München, 1998



A literary description of the most essential phenomena can also be found in:

R. Werth:

Berichte vom Rande des Bewusstseins

Verlag C. H. Beck


Reading: a complex activity

Reading is a complex activity involving different brain functions. The disruption of each of these brain functions can cause a reading disorder. What is usually referred to as “dyslexia” is a summary of reading disorders that can be traced back to different causes. As diverse as the causes of a reading disorder are, as diverse must the therapy procedures directed at these causes be.

In order to read a text fluently, the eyes must be directed to a specific point within a word for precisely calculated time intervals. During these time intervals the size of the word segment or word to be read must be determined, the word or word segment concerned must be seen “as a whole” and the corresponding sound sequence and the meaning of individual words and word sequences must be retrieved from memory. At the same time, the time and goal of the subsequent eye jump must be programmed. During the eye jump, visual functions must be suppressed and they must fully recover after the eye jump.

In order for these functions to function correctly, the complex interaction of numerous areas of the brain is required. These include structures of the visual system, structures that control visual attention, brain structures that produce various memory functions, and several areas of the brain that program and execute eye movements. Each of these structures of the brain can be disturbed in their function. The result is a reading disorder, the cause of which is not immediately apparent.


In a research project children with reading disorders of different causes were examined and a PC-supported diagnosis and therapy program was developed. The software contains both programs for the diagnosis of the causes of the reading disturbances and programs for the purposeful therapeutic removal or circumvention of these causes. For example, letters, letter combinations, word segments, words and texts are displayed on the monitor under such test conditions that they reveal the cause of the reading disorder and the reactions of the readers are measured by the computer. The exercise texts shown by means of a playback system are adapted to the type and severity of the reading disorder and processed in such a way that the parameters critical for reading can be controlled. Attractive texts from the first reading series were selected for this purpose. Special texts are developed for older readers. An integrated statistics program enables therapists, teachers and parents to monitor the development of reading performance and documents each reading progress.


The therapy part contains special exercises to improve (1) the ability to recognize letters, (2) the ability to simultaneously perceive and recognize letter sequences (words and word segments) (3) the retrieval of the sound sequences belonging to words and word segments, (4) increasing the attention field and reducing the interference of text segments with the recognition of other word segments or words, (5) improving the control of the length of fixation phases, and (6) improving the size, goal, and timing of gaze jumps during reading. The program automatically evaluates the performance of the readers in the tests and exercises performed and provides information on the level of performance achieved.

One study showed that in the case of certain reading disorders, about half of the children’s error rate decreased by 72% within half an hour if they received targeted training using the celeco reading learning method, in which critical parameters for reading were controlled. However, a control group that only practised reading texts could not improve their performance in the same time (Werth 2001).

The various causes that can cause a reading disorder (dyslexia), the possibilities to recognize them by suitable diagnostic means and successfully tested therapy methods are described in:

Werth R.
Dyslexia and other reading disorders

How to recognize and correct them

C.H. Beck
Munich, Germany

Selected papers

General definitions of terms for the articles in the topic area “Dyslexia” can be found as a PDF document here.

  • Werth R.
    Dyslexia Due to Visual Impairments. Biomedicines. 2023; 11(9):2559.
  • Werth R:
    Dyslexia: Causes and Concomittant Impairments.
    MDPI – Brain Sci. 2023, 13(3), 472; DOI: 10.3390/brainsci13030472
  • Werth R: A Scientific Approach to Conscious Experience, Introspection, and Unconscious Processing: Vision and Blindsight. Brain Sci. 2022, 12(10), 1305
  • Werth R: Is Developmental Dyslexia Due to a Visual and Not a Phonological Impairment? Brain Sci. 2021, 11(10), 1313
  • Werth R: Dyslexic Readers Improve without Training When Using a Computer-Guided Reading Strategy. Brain Sci. 2021, 11(5), 526
  • Werth R: What causes dyslexia? Identifying the causes of dyslexia and effective compensatory therapy
    Restorative Neurology and Neuroscience , November 2019 37(1):1-18 2019
  • Werth R: Rapid improvement of reading performance in children with dyslexia by altering the reading strategy: a novel approach to diagnoses and therapy of reading deficiencies. Restor Neurol Neurosci, vol. 36, no. 6, pp. 679-691 2018.
  • Werth R: Islam in Western Society. In: M. Krienke, E. Kuhn (eds.), Two Indispensable Topoi of Interreligious Dialogue. Tene Quod Bene, Vienna 2017, pp. 197-214.
  • Werth R: Willensfreiheit, Schuld und Sühne – Neuropsychologische und wissenschaftstheoretische Aspekte. In: Karimi M, Dziri A (Hrsg.), Freiheit im Angesicht Gottes. Kalam, Freiburg 2015, pp. 34-57.
  • Werth R: Der freie Wille ist beweisbar. In: Rodenstock R (Hrsg.), Willensfreiheit ist zwecklos. RHI, München 2015, pp. 71-99
  • Werth R: Explaining altered cerebral functioning following cerebral damage. Cortex. 2014; 56:26-9.
  • Werth R : Cerebral blindness and plasticity of the visual system in children. A review of visual capacities in patients with occipital lesions, hemispherectomy or hydranencephaly. Restor Neurol Neurosci 26 (2008), 377-389.
  • Werth R: Residual visual functions after loss of both cerebral hemispheres in infancy. Invest Ophthalmol Vis Sci 48 (2007), 3098-3106.
    Werth R: Visual functions without the occipital lobe or after cerebral hemispherectomy in infancy. European Journal of Neuroscience 24 (2006), 2932-2944.
  • Werth R, Schaedler G: Visual field loss in children and mentally handicapped adolescents receiving vigabatrin. Invest Ophthalmol Vis Sci 47 (2006), 3028-3035.
  • Werth R: Therapie von Lesestörungen durch Erkennen und Beheben der Ursachen Ergotherapie und Rehabilitation 9 (2006b) 6-10.
  • Werth R, Seelos K: Restitution of visual functions in cerebrally blind children. Neuropsychologia 43 (2005), 2011-2023.
  • Werth R, Moehrenschlager M: The development of visual functions in cerebrally blind children during a systematic visual field training. Restor Neurol Neurosci 15 (1999), 229-241.
  • Werth R, Steinbach Th: Symptoms of prosopagnosia in intoxicated subjects. Perceptual and Motor Skills 71 (1991), 399-412.
  • Werth R: The influence of culture and environment on the perception of time. International Journal of Psychophysiology 7 (1989), 436-437.
  • Werth R, Pöppel E: Pseudoneglect: Compression and lateral shift of mental coordinate sys -tems in a line bisection task. Neuropsychologia 26 (1988), 741-747.
  • Zihl J, Werth R: Contributions to the study of „blindsight“: I. Can stray light account for saccadic localization ability in patients with postgeniculate visual field defects? Neuropsychologia 22 (1984), 1-11.
  • Zihl J, Werth R: Contributions to the study of „blindsight“: II. The role of specific practice for saccadic localization performance in patients with postgeniculate visual field defects. Neuropsychologia 22 (1984), 13-22.


  • Werth R: Töten, Sterben und die Fiktion des Jenseits. celeco, München, in press
  • Werth, R. Die Natur des Bewusstseins – Wie Wahrnehmung und der freie Wille im Gehirn entstehen. C.H. Beck, München 2010.
  • Werth R: Legasthenie und andere Lesestörungen. C.H. Beck; München 2001. 3. erweiterte Auflage, C.H. Beck, München 2007.
  • Werth R: Hirnwelten. C.H. Beck; München 1998.
  • Werth R: Neglect nach Hirnschädigung – Unilaterale Verminderung der Aufmerksamkeit und Raumrepräsentation. Springer; Berlin, Heidelberg, New York, Tokyo 1988.
    Japanese edition: Springer; Tokyo 1991.
  • Werth R: Bewußtsein – psychologische, neurobiologische und wissenschaftstheoretische Aspekte. Springer; Berlin, Heidelberg, New York, Tokyo 1983.

All books have been published in German