Clinical assessment of the sensory ataxias; diagnostic algorithm with illustrative cases

Motor and sensory impairment in survivors of childhood central nervous system (CNS) tumors in the St. Jude Lifetime Cohort (SJLIFE)

BACKGROUND

Survivors of childhood central nervous system (CNS) tumors can develop motor and sensory impairment from their cancer and treatment history. We estimated the prevalence of motor and sensory impairment in survivors compared with controls through clinical assessment and identified associated treatment exposures and functional, quality of life (QOL), and social outcomes.

METHODS

Survivors of childhood CNS tumors from the St. Jude Lifetime Cohort (n = 378, median [range] age 24.0 [18.0-53.0] years, 43.4% female) ≥5 years from diagnosis and controls (n = 445, median [range] age 34.0 [18.0-70.0] years, 55.7% female) completed in-person evaluation for motor and sensory impairment using the modified Total Neuropathy Score. Impairment was graded by modified Common Terminology Criteria for Adverse Events. Multivariable models estimated associations between grade ≥2 motor/sensory impairment, individual/treatment characteristics, and secondary outcomes (function by Physical Performance Test, fitness by physiologic cost index, QOL by Medical Outcomes Survey Short Form-36 physical/mental summary scores, social attainment).

RESULTS

Grade ≥2 motor or sensory impairment was more prevalent in survivors (24.1%, 95% Confidence Interval [CI] 19.8%-29.4%) than controls (2.9%, CI 1.4-4.5%). Among survivors, in multivariable models, motor impairment was associated with vinca exposure <15 mg/m2 versus none (OR 4.38, CI 1.06-18.08) and etoposide exposure >2036 mg/m2 versus none (OR 12.61, CI 2.19-72.72). Sensory impairment was associated with older age at diagnosis (OR 1.09, CI 1.01-1.16) and craniospinal irradiation versus none (OR 4.39, CI 1.68-11.50). There were lower odds of motor/sensory impairment in survivors treated in the year 2000 or later versus before 1990 (Motor: OR 0.29, CI 0.10-0.84, Sensory: OR 0.35, CI 0.13-0.96). Motor impairment was associated with impaired physical QOL (OR 2.64, CI 1.22-5.72).

CONCLUSIONS

In survivors of childhood CNS tumors, motor and sensory impairment is prevalent by clinical assessment, especially after exposure to etoposide, vinca, or craniospinal radiation. Treating motor impairment may improve survivors' QOL.

Physiotherapy management focusing on proprioceptive impairment in a patient with gait and balance impairments following stroke: A case report

BACKGROUND

Proprioceptive impairment contributes to gait and balance impairments in patients with stroke. Diagnosis functional impairments and evaluation treatment efficacy require quantitative proprioception assessment. However, proprioception assessment has remained limited to ordinal scale measurement, with a lack of ratio scale measurements.

PURPOSE

This case report describes a physiotherapy management program focusing on proprioceptive impairment in patients with stroke using quantitative tests such as Threshold to Detect Passive Motion (TDPM) and Joint Position Sense (JPS).

CASE DESCRIPTION

A63-year-old male patient with an acute pontine lacunar infarction was admitted to our hospital. His muscle strength, selective movement, and trunk activity were preserved. However, the Berg Balance Scale (BBS) and Gait Assessment andIntervention Tool (GAIT) score were 42 and 9 points, observing balance impairment and the buckling knee pattern with hip ataxia during gait. Based on these, TDPM and JPS using image capture were performed. In physiotherapeuticdiagnosis, proprioceptive impairments in the hip and knee joints were the primary functional impairments related to balance and gait. To address these proprioceptive impairments, a 13-day treatment protocol incorporating transcutaneous electrical nerve stimulation (intensity: sensory threshold, frequency: 100 Hz) targeting the quadriceps femoris was performed.

OUTCOMES

The patient was discharged after achieving independent ambulation and improvement in BBS (56 points) and GAIT (2 points) scores, exceeding the minimum clinically important difference. Recovery of proprioceptive impairment corresponded withimproved balance and gait ability.

CONCLUSION

Quantitatively evaluating proprioceptive impairments may provide novel rehabilitation for patients with stroke who have proprioceptive impairments and contribute to clinical decision-making.

A missense mutation in the Hspa8 gene encoding heat shock cognate protein 70 causes neuroaxonal dystrophy in rats

Neuroaxonal dystrophy (NAD) is a neurodegenerative disease characterized by spheroid (swollen axon) formation in the nervous system. In the present study, we focused on a newly established autosomal recessive mutant strain of F344-kk/kk rats with hind limb gait abnormalities and ataxia from a young age. Histopathologically, a number of axonal spheroids were observed throughout the central nervous system, including the spinal cord (mainly in the dorsal cord), brain stem, and cerebellum in F344-kk/kk rats. Transmission electron microscopic observation of the spinal cord revealed accumulation of electron-dense bodies, degenerated abnormal mitochondria, as well as membranous or tubular structures in the axonal spheroids. Based on these neuropathological findings, F344-kk/kk rats were diagnosed with NAD. By a positional cloning approach, we identified a missense mutation (V95E) in the Hspa8 (heat shock protein family A (Hsp70) member 8) gene located on chromosome 8 of the F344-kk/kk rat genome. Furthermore, we developed the Hspa8 knock-in (KI) rats with the V95E mutation using the CRISPR-Cas system. Homozygous Hspa8-KI rats exhibited ataxia and axonal spheroids similar to those of F344-kk/kk rats. The V95E mutant HSC70 protein exhibited the significant but modest decrease in the maximum hydrolysis rate of ATPase when stimulated by co-chaperons DnaJB4 and BAG1 in vitro, which suggests the functional deficit in the V95E HSC70. Together, our findings provide the first evidence that the genetic alteration of the Hspa8 gene caused NAD in mammals.

Frontal ataxia: historical aspects and clinical definition

Frontal ataxia, originally described by Bruns, is characterized by the presence of signs of frontal lobe dysfunction, such as perseveration, paratonia, frontal release signs, cognitive changes, and urinary difficulty, associated with imbalance, slow gait, broad-based, the presence of postural instability and falls, retropulsion, and bradykinesia in the lower limbs. The goal of the present study is to recall the historical aspects of this condition, to draw attention to the importance of this clinical finding for the differential diagnosis of ataxias and to review the main semiological differences between primary ataxias (frontal, cerebellar, and sensory ataxia).

RNF170 mutation causes autosomal dominant sensory ataxia with variable pyramidal involvement

Background

Although hereditary ataxias are a group of clinically and genetically heterogeneous disorders, specific clinical clues can sometimes incriminate certain genes. This can trigger genetic testing in sporadic patients or prompt dissecting certain genes more thoroughly when initial genetic testing is negative. Also for the assembly of gene panels and interpretation of the results, genotype−phenotype correlations remain important to establish.

Methods

We clinically evaluated a Belgian family with autosomal dominant inherited sensory ataxia and variable pyramidal involvement and performed targeted clinical exome sequencing. Secondly, we retrospectively screened sequencing data of an in‐house cohort of 404 patients with neuromuscular disorders for variants in the identified gene RNF170.

Results

All affected family members showed sensory ataxia on examination. Pyramidal involvement, and sometimes slow‐pursuit abnormalities and/or a sensory neuropathy, were more variable findings. We identified the heterozygous variant p.Arg199Cys in RNF170 in all three affected siblings of our family. We did not find additional pathogenic variants in RNF170 in our in‐house neuromuscular cohort.

Conclusions

We confirm the heterozygous variant p.Arg199Cys in RNF170 in a Belgian family with autosomal dominant sensory ataxia and variable pyramidal involvement. This constitutes a rare but clinically recognizable phenotype that warrants testing of RNF170. Unlike the distinctive bi‐allelic loss of function variants in RNF170 associated with hereditary spastic paraplegia (HSP), the p.Arg199Cys variant is the only one reported in sensory ataxia. It is important for neurologists to be aware of this characteristic phenotype and to include this gene in gene panels for ataxia and HSP.

Hypocupraemia-induced anaemia, sensory ataxia and cognitive impairment secondary to zinc-containing dental adhesive

A 67-year-old man presented with 5 months of worsening memory impairment and sensory gait ataxia on the background of symptomatic anaemia. He experienced falls, agitation and became socially withdrawn over 3 weeks, resulting in hospital admission. On examination, he had sensory gait ataxia consistent with a dorsal column syndrome. He scored 13/30 on the Montreal Cognitive Assessment. Serum analysis showed normocytic anaemia and leucopenia, severe hypocupraemia, reduced caeruloplasmin and normal zinc levels. Overuse of zinc-containing denture cream was the cause of excess zinc ingestion and resultant copper deficiency, leading to blood dyscrasia and myelopathy. The cream was withdrawn and intravenous and then oral copper supplementation was implemented. Direct questions with regard to excess zinc in the diet and serological testing of copper and zinc should be considered in any patient with a dorsal column syndrome, particularly with concurrent anaemia. Copper deficiency may also have a role in exacerbating pre-existing cognitive impairment.

Clinical Recognition of Sensory Ataxia and Cerebellar Ataxia

Ataxia is a kind of external characteristics when the human body has poor coordination and balance disorder, it often indicates diseases in certain parts of the body. Many internal factors may causing ataxia; currently, observed external characteristics, combined with Doctor’s personal clinical experience play main roles in diagnosing ataxia. In this situation, different kinds of diseases may be confused, leading to the delay in treatment and recovery. Modern high precision medical instruments would provide better accuracy but the economic cost is a non-negligible factor. In this paper, novel non-contact sensing technique is used to detect and distinguish sensory ataxia and cerebellar ataxia. Firstly, Romberg’s test and gait analysis data are collected by the microwave sensing platform; then, after some preprocessing, some machine learning approaches have been applied to train the models. For Romberg’s test, time domain features are considered, the accuracy of all the three algorithms are higher than 96%; for gait detection, Principal Component Analysis (PCA) is used for dimensionality reduction, and the accuracies of Back Propagation (BP) neural Network, Support Vector Machine (SVM), and Random Forest (RF) are 97.8, 98.9, and 91.1%, respectively.

Assessing risk factors of falls in cancer patients with chemotherapy-induced peripheral neurotoxicity

AIM

To identify the risk factors of falls in a well-characterized cohort of cancer patients with chemotherapy-induced peripheral neurotoxicity (CIPN).

PATIENTS AND METHODS

We studied 122 cancer patients experiencing any grade of CIPN, following completion of different chemotherapeutic regimens for various non-hematological malignancies. The results of the clinical examination were summarized by means of the Total Neuropathy Score-clinical version (TNSc®). A neurophysiological examination was also carried out.

RESULTS

Among 122 patients, 21 (17.2%) of them reported falls. These were 7 males and 14 females with a mean age of 57.3 ± 8.1 years. All of them (21; 100%) had grade 3 CIPN, according to TNSc® with a median value of 15. Univariate analysis showed that the following variables were strongly associated with falls: TNSc® score of > 14 corresponding to grade 3 CIPN, evidence of motor impairment, evidence of sensory ataxia with positive Romberg sign, and decrease of sural a-SAP > 50% from the baseline value. Multivariate regression analysis failed to define independent predictors of falls. However, ROC analysis demonstrated that a discriminative TNSc® cutoff value of > 14 predicted falls with a sensitivity of 100% and specificity of 87%, whereas sensory ataxia predicted falls with a sensitivity of 95% and specificity of 83%.

CONCLUSION

Grade 3 CIPN, as assessed with TNSc®, and evidence of sensory ataxia with a positive Romberg sign were strongly associated with an increased risk of falls. Although our results need further validation, the TNSc® scale appears to be a practical and easy tool for identifying patients at higher risk of falling.

A "matched" sensory reference can guide goal-directed movements of the affected hand in central post-stroke sensory ataxia

Patients with central post-stroke sensory ataxia (CPSA) suffer from not only somatosensory dysfunction but also the ataxic movement disorder of the affected limb. These sensory and motor impairments possibly interfere each other, but such interference is still unclear. We evaluated smoothness of grasp movements in CPSA patients using a kinematic analysis, and verified the effect of somatosensory reference from the intact hand on grasp movements. Eight CPSA patients were enrolled. We recorded their reach-and-pinch movements of both affected and intact hands toward the tip of the 3-cm-diameter vertical bar, using a three-dimensional measurement system. When executing these movements of one hand, the patients simultaneously pinched the same diameter bar as the goal tip (matched-reference condition: Matched-Ref) or the 5-cm-diameter thicker bar (mismatched-reference condition: Mismatched-Ref) by the other hand. The normalized jerk index (i.e., movement smoothness) of the affected hand was disturbed compared with the intact hand. The kinematic data of the finger opening and closing phases were also disturbed. These disturbances were partially improved with Matched-Ref but not Mismatched-Ref of the intact hand. We successfully evaluated the features of CPSA, indicating that the somatosensory reference method could be useful for rehabilitation in sensory ataxia.

Zinc containing dental fixative causing copper deficiency myelopathy

A 62-year-old male, previously well, was referred to neurology clinic following 6 months history of worsening lower limbs instability, paraesthesia, pain and weakness rendering him housebound. Examination revealed upper motor neuron pattern of weakness of the lower limbs and loss of proprioception. Serum analysis revealed reduced caeruloplasmin and copper levels with raised zinc. Spinal imaging revealed subtle dorsal column intensity changes in C2-C7, confirmed with 3T MRI. A copper deficiency myeloneuropathy was diagnosed secondary to chronic use of a zinc-containing dental fixative paste. The paste was discontinued and a copper supplementation was started. Resolution of symptoms was not achieved with intensive physiotherapy. The patient remains a wheelchair user though progression of symptoms has halted. Prompt recognition and treatment of hyperzincaemia-induced hypocupraemia earlier in the disease course may have prevented any irreversible neurological deficit.