LSTM-CNN: An efficient diagnostic network for Parkinson's disease utilizing dynamic handwriting analysis

BACKGROUND AND OBJECTIVES

Dynamic handwriting analysis, due to its noninvasive and readily accessible nature, has emerged as a vital adjunctive method for the early diagnosis of Parkinson's disease (PD). An essential step involves analysing subtle variations in signals to quantify PD dysgraphia. Although previous studies have explored extracting features from the overall signal, they may ignore the potential importance of local signal segments. In this study, we propose a lightweight network architecture to analyse dynamic handwriting signal segments of patients and present visual diagnostic results, providing an efficient diagnostic method.

METHODS

To analyse subtle variations in handwriting, we investigate time-dependent patterns in local representation of handwriting signals. Specifically, we segment the handwriting signal into fixed-length sequential segments and design a compact one-dimensional (1D) hybrid network to extract discriminative temporal features for classifying each local segment. Finally, the category of the handwriting signal is fully diagnosed through a majority voting scheme.

RESULTS

The proposed method achieves impressive diagnostic performance on the new DraWritePD dataset (with an accuracy of 96.2%, sensitivity of 94.5% and specificity of 97.3%) and the well-established PaHaW dataset (with an accuracy of 90.7%, sensitivity of 94.3% and specificity of 87.5%). Moreover, the network architecture stands out for its excellent lightweight design, occupying a mere 0.084M parameters, with only 0.59M floating-point operations. It also exhibits nearly real-time CPU inference performance, with the inference time for a single handwriting signal ranging from 0.106 to 0.220 s.

CONCLUSIONS

We present a series of experiments with extensive analysis, which systematically demonstrate the effectiveness and efficiency of the proposed method in quantifying dysgraphia for a precise diagnosis of PD.

The Modularity of Dysgraphia

Research regarding dysgraphia, an impairment in writing, is attaining more attention in recent times. The existing studies on dysgraphia draw insights from cognitive, behavioural, neurological, and genetic fields of knowledge. However, these multiple studies on dysgraphia fail to illustrate how these cognitive, behavioural, neurological, and genetic systems interact and intersect in dysgraphia. Therefore, the studies could not offer a comprehensive understanding of dysgraphia. In order to fill this gap, the review attempts to study dysgraphia using the notion of modularity by accommodating insights from cognitive, behavioural, neurological, and genetic aspects of dysgraphia. Such a profound understanding could facilitate an early diagnosis and holistic intervention towards dysgraphia.

Functional Assessment of Handwriting Among Children: A Systematic Review of the Psychometric Properties

IMPORTANCE

Handwriting legibility and speed assessments have a critical role in identifying and evaluating handwriting problems, which are common among children.

OBJECTIVE

The objective was to evaluate the psychometric properties and clinical utility of handwriting assessments for children ages 3 to 16 yr.

DATA SOURCES

A systematic review was conducted in CINAHL, PubMed (MEDLINE), Scopus, and education databases, with no time limits. The search strategy included a combination of the following keywords: handwriting, write, children, assessment, and validity. The exclusion criteria were assessment tools that were electronic, that focused on cognitive components of handwriting, or that only evaluated alphabets other than Latin.

STUDY SELECTION AND DATA COLLECTION

The systematic review was carried out on the basis of the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations. The protocol was registered in the Prospective Register of Systematic Reviews (PROSPERO).

FINDINGS

The 14 included instruments had a total sample of 4,987 children. Internal consistency ranged from moderate (.73; Writing Readiness Inventory Tool in Context) to high (.98; Letter Writing). The interexaminer reliability values of the 11 direct assessment instruments ranged from .77 (Systematic Screening for Handwriting Difficulties) to 1.00 (Handwriting Speed Test).

CONCLUSIONS AND RELEVANCE

In this systematic review, existing tools were evaluated by clinical utility and the quality of psychometric properties. Direct assessments showed good psychometric properties. Indirect and self-assessment tools demonstrated poor psychometric properties. Further research on screening tools and tools in other languages is needed. What This Article Adds: Specific learning disorders (e.g., dysgraphia) negatively affect academic learning and, when prolonged in time, self-concept. However, handwriting legibility and speed assessments could be used to identify and evaluate these learning disorders if an early referral to occupational therapy is carried out.

Two types of developmental surface dysgraphia: to bee but not to bea

We report on two types of developmental surface dysgraphia. One type, exhibited by 8 participants, is orthographic lexicon surface dysgraphia, which involves an impairment in the orthographic output lexicon, leading to nonword phonologically-plausible misspellings. The other type, shown by 3 participants, is disconnection surface dysgraphia. In this type, the orthographic output lexicon is disconnected from the semantic system and from the phonological input lexicon, but still contributes to spelling via support to the orthographic output buffer, resulting in mainly lexical phonologically-plausible misspellings (writing be as "bee" but not "bea").The specific localization of the impairment in spelling, in the lexicon or in its connections, allowed us to examine the question of one or two orthographic lexicons; four participants who had a deficit in the orthographic output lexicon itself in writing had intact orthographic-input-lexicon in reading. They made surface errors in writing but not in reading the same words, supporting separate input and output orthographic lexicons.

Investigating Visual Perception Impairments through Serious Games and Eye Tracking to Anticipate Handwriting Difficulties

Dysgraphia is a learning disability that causes handwritten production below expectations. Its diagnosis is delayed until the completion of handwriting development. To allow a preventive training program, abilities not directly related to handwriting should be evaluated, and one of them is visual perception. To investigate the role of visual perception in handwriting skills, we gamified standard clinical visual perception tests to be played while wearing an eye tracker at three difficulty levels. Then, we identified children at risk of dysgraphia through the means of a handwriting speed test. Five machine learning models were constructed to predict if the child was at risk, using the CatBoost algorithm with Nested Cross-Validation, with combinations of game performance, eye-tracking, and drawing data as predictors. A total of 53 children participated in the study. The machine learning models obtained good results, particularly with game performances as predictors (F1 score: 0.77 train, 0.71 test). SHAP explainer was used to identify the most impactful features. The game reached an excellent usability score (89.4 ± 9.6). These results are promising to suggest a new tool for dysgraphia early screening based on visual perception skills.

Co-Occurrence of Reading and Writing Difficulties: The Application of the Interactive Dynamic Literacy Model

This article presents the application of the interactive dynamic literacy (IDL) model (Kim, 2020b) toward understanding difficulties in learning to read and write. According to the IDL model, reading and writing are part of communicative acts that draw on largely shared processes and skills as well as unique processes and skills. As such, reading and writing are dissociable but interdependent systems that have hierarchical, interactive, and dynamic relations. These key tenets of the IDL model are applied to the disruption of reading and writing development to explain co-occurrence of reading-writing difficulties using a single framework. The following hypotheses are presented: (a) co-occurrence between word reading and spelling and handwriting difficulties; (b) co-occurrence of dyslexia with written composition difficulties; (c) co-occurrence between reading comprehension and written composition difficulties; (d) co-occurrence of language difficulties with reading difficulties and writing difficulties; (e) co-occurrence of reading, writing, and language difficulties with weak domain-general skills or executive functions such as working memory and attentional control (including attention-deficit/ hyperactivity disorder [ADHD]); and (f) multiple pathways for reading and writing difficulties. Implications are discussed.

'I think writing is everything': An exploration of the writing experiences of people with aphasia

BACKGROUND

Written communication has become an increasingly important part of everyday life in social, educational and professional spheres. The substantial increase in writing via the internet and mobile technologies provides both an opportunity for social engagement and distinct challenges for people with aphasia. Within the current literature there has been limited research into the lived experiences of people with aphasia of their writing difficulties and how these affect their ability to communicate.

AIMS

This qualitative study aimed to explore the experiences of people with aphasia of living with language-related writing difficulties and the impact of these on their lives.

METHODS & PROCEDURES

Eight people with post-stroke aphasia and writing difficulties took part in semi-structured interviews. The interviews were analysed using inductive reflexive thematic analysis.

OUTCOMES & RESULTS

Two themes were found in the data. The first theme was a gradual and effortful improvement to writing: Participants described how writing had improved since their stroke due to strategies and support, but they still found writing to be difficult and frustrating and described many barriers to writing. The second theme was the importance of writing for fulfilling adult social roles: Participants found writing to be important for communicating with family, friends and organizations, but their participation in society and self-esteem and confidence were impacted by writing difficulties; reduced social roles meant reduced need for writing, but participants were still motivated to work towards writing goals.

CONCLUSIONS & IMPLICATIONS

The findings demonstrate the emerging importance of writing skills for people with aphasia with respect to communication, well-being, participation and inclusion in society, and carrying out social roles. They provide an insight into the process of improvement, including the difficulties, facilitators and barriers. Implications for speech and language therapy assessment and management are discussed.

WHAT THIS PAPER ADDS

What is already known on the subject People with aphasia have difficulties with writing that can affect their ability to communicate. A small body of qualitative research has provided insights into individuals' experiences of literacy difficulties. More research is needed to understand the writing experiences of people with aphasia to help design appropriate assessments and interventions. What this paper adds to existing knowledge Participants experienced gradual and effortful improvement since their stroke. They felt negative about aspects of their writing, including speed, accuracy and range of vocabulary. Writing was facilitated through assistive technologies, spelling practice and support from others; barriers included technology, lack of time, stroke-related symptoms and others' lack of awareness about aphasia. Participants considered writing skills to be important, particularly for communication, carrying out adult social roles and participating in society, and were therefore still working towards goals related to everyday writing activities. What are the potential or actual clinical implications of this work? This study suggests that speech and language therapy assessment should include interviewing participants about their activities, strengths, difficulties, facilitators and barriers in writing, and informal assessment of a range of functional writing tasks. Intervention should be tailored to the individual's needs. This should include meaningful activities that relate to functional everyday writing and, where appropriate, self-management, compensatory technologies and group approaches, while making use of existing strategies identified by the individual.

The memory for words: Armand Trousseau on aphasia

Of all the nineteenth-century physicians whose names still resonate today, Armand Trousseau is perhaps the one most familiar, for his description of carpal spasm as a sign of hypocalcemia (Trousseau's sign) and his description of the hypercoagulable state associated with cancer (Trousseau's syndrome). In the last three years of his life, Trousseau turned his attention to aphasia, which he included in his 1864 and 1865 lectures given at Hôtel-Dieu Hospital in Paris and which he discussed in an address to the Imperial Academy of Medicine in 1865. Trousseau preceded Wernicke in describing aphasia as a symptom complex, in which he included Broca's aphemia, receptive aphasia, the inability to read with and without the inability to write (alexia with and without agraphia), the inability to name common objects (amnesic aphasia or anomia) and to recognize numbers (acalculia), and the inability to draw. Trousseau concluded that such a varied symptomatology could not arise from a single area, and he proposed that lesions of the posterior inferior frontal convolution identified by Broca, of the insula and corpus striatum and of the temporal and parietal lobes, could give rise to aphasia. The role of the posterior temporal lobe in receptive aphasia was confirmed by Wernicke in 1874, and the role of the inferior parietal lobule in agraphia and alexia was confirmed by Dejerine in 1891. Trousseau thought that aphasia resulted from the loss of the memory for words and for the synergistic actions of the movements of articulations learned in early childhood. Trousseau added inattention, lack of comprehension, and cognitive decline to amnesia as contributing factors to the verbal and nonverbal expression of thought. Trousseau constructed a comprehensive theory of aphasia that unified its semiology, localization, and pathophysiology. This construct had the virtue of being predictive and falsifiable by the clinico-pathological method. Through insight born of observation, Trousseau identified the issues that dominated aphasiology into the twenty-first century.

Dementia with Lewy Bodies with Pure Agraphia for Kanji (Japanese Morphograms)

A 70-year-old dextral woman was admitted to a hospital with agraphia for kanji (Japanese morphograms). She had a history of severe constipation, nightmares, and visual hallucinations. Neurological examinations revealed no obvious Parkinson's disease symptoms. She showed poor skills in writing the kanji for looking at picture objects, [e.g., writing the Japanese word "inu" (which means dog) when she saw a drawing of a dog] or dictated words. A reduced striatal uptake of [¹²³I]-2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl) nortropane (FP-CIT) on single-photon-emission computed tomography and reduced meta-iodobenzylguanidine (MIBG) cardiac uptake on myocardial scintigraphy were detected. The accumulation of amyloid beta in the bilateral cerebral cortices was observed on amyloid-positron emission tomography. We herein report a case of Lewy body dementia with pure agraphia for kanji with underlying Alzheimer's disease pathology.

A Tablet-Based App to Discriminate Children at Potential Risk of Handwriting Alterations in a Preliteracy Stage

Failing to master handwriting, as in the case of Dysgraphia, has negative consequences on children's lives. In early stage of development, Dysgraphia diagnosis is delayed and not easily achievable. Thus, the aim of this work is to propose a valid tool to anticipate Dysgraphia screening at a preliteracy age. We developed a tablet application to analyze characteristics altered in dysgraphic handwriting, such as rhythmical laws (isochrony and homothety), or a collection of kinematic and dynamic parameters (smoothness, pressure, frequency contents). To be suitable for the pre-literacy stage, possible alterations are investigated in symbol drawings. The app is tested on 104 preschoolers, both with normal (n=76) and delayed graphical abilities (n=28), reporting excellent acceptance. Some isochrony alterations were reported only for children with delayed graphical abilities. Moreover, kinematic and dynamic parameters are effective in discriminating between risk and norisk conditions. Indeed, the logistic classification adopted resulted in a 0.819 area under the precision-recall curve. These findings pave the way toward an early screening of future handwriting alteration, starting from a pre-literacy age.

Modified semantic feature analysis for anomia: a single case study

Semantic feature analysis (SFA) is a treatment approach designed for patients with lexical retrieval difficulty caused by semantic deficits. During training, a structured framework (e.g. requiring the patient to name the category, function, and colour of the target items) is usually provided to facilitate the patient in thinking of the semantic features of the target items. Nevertheless, the use of a structured framework potentially limits the variety of semantic features activated for lexical retrieval. This study investigated the effectiveness of modified SFA training to address this potential limitation. An odd-man-out task was carried out in the modified SFA training with an anomic patient with impaired access to the phonological output lexicon. The task aimed to encourage a detailed comparison of semantic features among items in the same category. It is hypothesized that activations of more distinctive semantic features belonging to the target items will result in greater extent of generalizations in the lexical processing. The patient's abilities in naming semantic features at the beginning and at the end of each treatment session were compared. Besides, accuracy and error patterns in oral and written naming in the initial and post-treatment assessment were also compared. The results showed a significant increase in the number of semantic features retrieved within treatment sessions. Moreover, a significant improvement in oral picture naming was also observed subsequent to the modified SFA training. Finally, the results of the error analyses further supported that the modified SFA was effective in promoting overall lexical processing. The findings indicated that both quantity and distinctiveness of concepts activated in the semantic system are essential to effective lexical retrieval. Theoretical and clinical implications were also discussed.

Serial order and consonant-vowel structure in a graphemic output buffer model

We review features of the spelling errors of dysgraphic patients with "Graphemic Buffer Disorder" (GBD). We argue that the errors made by such patients suggest the breakdown of a system used to generate serial order in the output stages of spelling production, and we develop a model for this system based on an existing theory of sequential behaviour--"Competitive Queuing." We show that constraints on response categories may be straightforwardly applied during sequence production in such a model, and this enables us to account for the preservation of consonant-vowel status in the spelling errors of GBD patients. When the sequence generation process is disrupted by the addition of random noise the model shows the major features of GBD. The results are compared in detail against data from a number of patients.

[Writing, aging and Alzheimer's disease]

Writing is a complex and fragile cognitive function, that appeared very late in the history of mankind, and that also develops quite late in individuals. Aging does not induce changes in the lexical, semantic and syntaxic parameters of the writing description of a complex image. In the same way, spelling is not significantly altered through aging. Spelling errors are rare among seniors: they only concern infrequent words and mostly respect their pronunciation. The most frequent errors are about accents or double letters. Margins get smaller, seniors raise their pens less often and the pressure and width of writing decrease with age. Writing get progressively disorganized during Alzheimer's disease. The content of texts is primarily affected, texts becoming shorter and less coherent. Then, spelling is altered by regularization errors which are an evidence of lexical agraphia. Then, lexical agraphia gets worse and rapidly becomes mixed, combining lexical and phonological features. Finally, dementia worsens along with a massive deterioration of graphic features and spatial organization. Agraphia of Alzheimer's disease comes from a progressive and hierarchized disorganization of the various components of language and writing, due to the brain lesions in several associative areas, i.e. the parietal, temporal, occipital and frontal regions.

Surface dysgraphia in a regular orthography: apostrophe use by an Italian writer

The dual-route model of writing assumes two basic procedures involved in writing: lexical and non-lexical. The lexical route is fundamental in opaque orthographies such as English; from its impairment surface dysgraphia arises. Evidence for the role of a lexical route in transparent languages such as Italian, which have a regular orthography, has been more limited. We report a case study of ES, an Italian patient suffering from degenerative brain disease, who presented with a selective disorder of writing. He showed the unusual phenomenon of inserting an apostrophe inappropriately in the spellings of words. Neuropsychological evaluation provided evidence of loss of orthographic meaning of the apostrophe and a pattern of writing performance consistent with surface dysgraphia. There was also evidence of an accompanying surface dyslexia. We conclude that examination of apostrophe use provides a valuable means of detecting surface dysgraphia in the Italian language. The findings point to the need for cognitive models of writing to account for "dumb symbols" of language such as the apostrophe. This unique case provides a further example of the variety of clinical presentations of focal cerebral degeneration.

Evolution of a form of pure alexia without agraphia in a child sustaining occipital lobe infarction at 2 1/2 years

The progress of cognitive visual dysfunction over an 8-year period of a child who sustained bilateral occipital-lobe infarctions at the age of 2 1/2 years is described. She survived with normal intelligence and went on to attend mainstream school. She manifested many features of cognitive visual impairment and, in particular, developed a form of pure alexia without agraphia. She achieved some letter-by-letter reading but no sight vocabulary development, including to her own name. She learned to write imaginatively employing phonetically true spelling but cannot read what she has written. Her progress and the difficulties encountered during the management of her condition are discussed in this first case report of the evolution of pure alexia without agraphia in childhood. The features of this syndrome in the developing child who has never developed the capacity to read are contrasted with that seen in affected adults.

[Language and aphasias]

INTRODUCTION AND OBJECTIVE

Approximately 400,000 years ago men started to use language. Initially it was probably poor with few phonemes. With social evolution it became more complex, with the appearance of new phonemes and a more complete grammatical structure. The current concept of the processing of language dates, with little change, from the nineteenth century.

DEVELOPMENT

With the birth of phrenology language began to be studied. This lead to the hypothesis of Wernicke, with two main areas joined by the fasciculo arcuato, which is still held to be valid with modifications by Gerchwind and Damasio, amongst others. Important advances in the study of language are due to Chomsky and his transformational grammar. This supports the universal structure of language, since one learns it following genetically determined laws. Language has three main aspects: creativity which makes both the transmitter and the receiver active participants in communication, the form from which words are constructed and the content of the message. Aphasia is an alteration in the comprehension and understanding of language, which may be the clinical expression of many different aetiologies. They help us to localize the lesion topographically. They are divided depending on the clinical signs, into motor or Broca's aphasia, in which understanding is conserved but the patient uses a language with poor grammatical structure, although the semantic content is acceptable: sensitive or Wernicke's aphasia, with inability to understand and language which is fluid but unintelligible; conduction aphasia due to limitation in the transmission of impulses from Wernicke's area to that of Broca, with acceptable understanding and fluid language and the trans-cortical aphasias where the main characteristic is indemnity of the capacity of repetition.

CONCLUSIONS

The aphasias, as the expression of an alteration of language are an important support in the topographical localization of lesions, even before these can be shown on computerized tomography.

Pure alexia without agraphia: a classical cortical syndrome revisited

A patient who developed pure alexia without agraphia following a stroke is described. An infarction of the left occipital pole was demonstrated by Magnetic Resonance Imaging (MRI). The literature on this rare syndrome is reviewed, and the localisation of damage in relation to the clinical findings discussed.

[Anatomical and clinical correlations in a case of alexia without agraphia (author's transl)]

The authors report the anatomical and clinical findings observed in a case of alexia iwthout agraphia due to left posterior cerebral artery infarction, in which there were lesions of the occipital and thalamic regions, the splenium of the corpus callosum, and the hippocampus. They discuss, more particularly, the memory difficulties, and the objects naming trouble.

Functional disconnection sydrome

We have described a patient who suffered from agnostic alexia without agraphia, accompanied by color agnosia. The alexia affected languages read in opposite directions. The patient was found to have a vascular malformation of the left posterior cerebral artery. This case is outstanding because of the patient’s complete recovery from the alexia in all the languages she knew. In an attempt to explain the process of recovery from agnostic alexia, we have introduced a new concept, that of ‘functional disconnection syndrome’.